- Off-Highway Truck/Tractor
- All
Introduction
Revision | Summary of Changes in SEBF8083 |
---|---|
21 | Significant revision, added carbon fiber snap gages and updated clarity of crack repair.
Inserted contents from SEBF2167Reuse And Salvage Guideline, "Thermal Spray Procedures for OHT Rear Spindles" into this media. |
20 | Updated dimensions and added |
© 2019 Caterpillar All Rights Reserved. This guideline is for the use of Cat dealers only. Unauthorized use of this document or the proprietary processes therein without permission may be violation of intellectual property law.
Information contained in this document is considered Caterpillar: Confidential Yellow.
This Reuse and Salvage Guideline contains the necessary information to allow a dealer to establish a parts reusability program. Reuse and salvage information enables Caterpillar dealers and customers to benefit from cost reductions. Every effort has been made to provide the most current information that is known to Caterpillar. Continuing improvement and advancement of product design might have caused changes to your product which are not included in this publication. This Reuse and Salvage Guideline must be used with the latest technical information that is available from Caterpillar.
For technical questions when using this document, work with your Dealer Technical Communicator (TC).
To report suspected errors, inaccuracies, or suggestions regarding the document, submit a form for feedback in the Service Information System (SIS web) interface.
Canceled Part Numbers and Replaced Part Numbers
This document may include canceled part numbers and replaced part numbers. Use the Numerical Part Record (NPR) on the Service Information System Website (SIS web) for information about canceled part numbers and replaced part numbers. NPR will provide the current part numbers for replaced parts.
Important Safety Information
Illustration 1 | g02139237 |
Work safely. Most accidents that involve product operation, maintenance, and repair are caused by failure to observe basic safety rules or precautions. An accident can often be avoided by recognizing potentially hazardous situations before an accident occurs. A person must be alert to potential hazards. This person should also have the necessary training, skills, and tools to perform these functions properly. Safety precautions and warnings are provided in this instruction and on the product. If these hazard warnings are not heeded, bodily injury or death could occur to you or to other persons. Caterpillar cannot anticipate every possible circumstance that might involve a potential hazard. Therefore, the warnings in this publication and the warnings that are on the product are not all inclusive. If a tool, a procedure, a work method, or operating technique that is not recommended by Caterpillar is used, ensure that it is safe for you and for other people to use. Ensure that the product will not be damaged or the product will not be made unsafe by the operation, lubrication, maintenance, or the repair procedures that are used.
Improper operation, lubrication, maintenance or repair of this product can be dangerous and could result in injury or death. Do not operate or perform any lubrication, maintenance or repair on this product, until you have read and understood the operation, lubrication, maintenance and repair information. |
Safety precautions and warnings are provided in this manual and on the product. If these hazard warnings are not heeded, bodily injury or death could occur to you or to other persons.
The hazards are identified by the “Safety Alert Symbol” which is followed by a “Signal Word” such as “DANGER”, “WARNING” or “CAUTION”. Refer to Illustration 2 for an example of a “WARNING” Safety Alert Symbol.
Illustration 2 | g00008666 |
This safety alert symbol means:
Pay Attention!
Become Alert!
Your safety is Involved.
The message that appears under the safety alert symbol explains the hazard.
Operations that may cause product damage are identified by "NOTICE" labels on the product and in this publication.
Caterpillar cannot anticipate every possible circumstance that might involve a potential hazard. The safety information in this document and the safety information on the machine are not all inclusive. Determine that the tools, procedures, work methods, and operating techniques are safe. Determine that the operation, lubrication, maintenance, and repair procedures will not damage the machine. Also, determine that the operation, lubrication, maintenance, and repair procedures will not make the machine unsafe.
The information, the specifications, and the illustrations that exist in this guideline are based on information which was available at the time of publication. The specifications, torques, pressures, measurements, adjustments, illustrations, and other items can change at any time. These changes can affect the service that is given to the product. Obtain the complete, most current information before you start any job. Caterpillar dealers can supply the most current information.
Summary
This guideline provides the procedures that are necessary to determine the reusability for rear spindles on Off-Highway Trucks. Life will vary depending on application, load, lubrication, and environment.
This guideline contains the latest standards of engineering, which will help minimize owning and operating costs. A part is expected to reach the next Planned Component Rebuild (PCR) if the part meets the specifications within this guideline and the part is intended for a similar application. Use this guideline to determine whether a part should be reused. Do not install a part that is not reusable. During reconditioning, correct any condition that might have caused the original failure.
The dimensions and tolerances provided are to return a part / component to specification. The dimensional information alone is not solely used to condemn a part from reuse. Follow visual inspections and the "Crack Detection Methods" section for further guidance.
References
References | |
---|---|
Media Number | Publication Type & Title |
Channel1 | "Why Reuse and Salvage Parts" |
https://channel1.mediaspace.kaltura.com/media/Why+Reuse+and+Salvage+Parts/0_ae9rhu2z | |
PERJ1017 | Special Publication
"Dealer Service Tools Catalog" |
SEBD0512 | Reuse and Salvage Guidelines
"Caterpillar Service Welding Guide" |
SEBF8187 | Reuse and Salvage Guidelines
"Standardized Parts Marking Procedures" |
SEBF8728 | Reuse and Salvage Guidelines
"Specifications for Inspection of Driveline Fasteners" |
SEBF8882 | Reuse and Salvage Guidelines
"Using Lock-N-Stitch Procedures for Casting Repair" |
SEBF9236 | Reuse and Salvage Guidelines
"Fundamentals of High Velocity Oxygen Fuel (HVOF) Spray for reconditioning Components" (1) |
SEBF9238 | Reuse and Salvage Guidelines
"Fundamentals of Arc Spray for reconditioning Components" (1) |
SEHS8792 | Special Instruction
"Using Caterpillar Replacement Thread Inserts" |
(1) | Only Cat dealers may utilize applications for Thermal Spray. The processes must be carried out within the facilities of the dealership. The dealership must maintain a clean environment and always use the correct equipment for all processes in each Thermal Spray Application. |
Service Advisories, Service Letters, and Technical Service Bulletins
NOTICE |
---|
The most recent Service Advisories, Service Letters, and Technical Service Bulletins that are related to this component should be reviewed before beginning work. Often Service Advisories, Service Letters, and Technical Service Bulletins contain upgrades in repair procedures, parts, and safety information which pertain to the components being repaired. |
Tooling and Equipment
NOTICE |
---|
Failure to follow the recommended procedure or the specified tooling that is required for the procedure could result in damage to components. To avoid component damage, follow the recommended procedure using the recommended tools. |
Note: The Tooling and Equipment in Table 3 is not an all inclusive list of Tooling required to perform every task within this document. Tooling needs may vary for the scope of work to be performed for each specific rebuild.
Required Tooling and Equipment | ||
---|---|---|
Part Number | Description | Designation |
— (1) | Personal Protective Equipment (PPE) | Personal Protection |
— (2) | Clevis/ Shackle | Component
Repositioning and Movement |
— (2) | Lifting Eye Assemblies | Component
Repositioning and Movement |
— (2) | Tool (Cribbing) | Component
Repositioning and Movement |
— | Suitable Lifting Device | Component
Repositioning and Movement |
Telescoping Magnet | General Tooling | |
Automatic Tape Measure (1-inch X 26- ft)
|
Measurement
Checks |
|
Caliper
|
Profile
Measurement |
|
Feeler Gauge
|
Thickness
Measurement Checks |
|
Tool
Rule |
Measurement
Checks |
|
90141-2 (3) | Instrument Group
Carbon Fiber Snap Gages Gage to Check |
External
Measurement Checks |
92268-2 (3) | Instrument Group
Carbon Fiber Snap Gages Gage to Check |
External
Measurement Checks |
92270-2 (3) | Instrument Group
Carbon Fiber Snap Gages Gage to Check |
External
Measurement Checks |
92531-2 (3) | Instrument Group
Carbon Fiber Snap Gages Gage to Check |
External
Measurement Checks |
92718-2 (3) | Instrument Group
Carbon Fiber Snap Gages Gage to Check |
External
Measurement Checks |
Tool (Level)
|
Level | |
—
and /or — |
GO/NO-GO Thread Gauge Set, Metric | Threaded Hole
Inspection |
GO/NO-GO Thread Gauge Set, SAE | ||
— (2) | Plastic Plug Assortment | Threaded Hole
Protection |
— (2) | Tap and Die Set | Threaded Hole
/ Restore |
Disc (Coarse) | Surface
Preparation / De-burring |
|
Threaded Shaft | Surface
Preparation / De-burring |
|
Holder (Disc Pad) | Surface
Preparation / De-burring |
|
Grinding Wheel (F-Grade)
(120 Grit) |
Surface
Preparation / De-burring |
|
Polishing Stone | Polishing | |
Brush | General Cleaning | |
Abrasive Material (Roll) | General Cleaning | |
Surface Reconditioning Pad (180 Grit) | General Cleaning | |
Towel | General Cleaning | |
Metal Marking Pen | Parts Marking | |
Detroit Hardness Tester | Hardness Check | |
— | GE MIC 10 Hardness Tester | Hardness Check |
Tool Group
Dial Indicator |
Run-Out Checks | |
Indicator Contact Point | Run-Out Checks | |
Seal Pick
Kit |
Gear/ Shaft
Step Inspection |
|
Microscope (40-Power)
|
Crack/
Measurement Inspection |
|
Tool (Ruler)
|
Measurement
Checks |
|
Micrometers
External |
External
Measurement Checks |
|
Tool
Specimen |
Surface Texture
Tester |
|
Instrument Group
Micrometer, Outside 2.00 - 6.00 inch |
External
Measurement Checks |
|
Instrument Group
Micrometer, Outside - Digital |
External
Measurement Checks |
|
Pin Set
|
Measurement
Over Pin / MOP Spline Wear Inspection |
|
Pin Set
|
Measurement
Over Pin / MOP Spline Wear Inspection |
|
Tool (Magnet) (6) | Gage Pin Magnetizer/ Demagnetizer | |
— | Precision Gage Pins (7)(7)
x |
Measurement
Over Pin / MOP Spline Wear Inspection |
— | Precision Gage Pins (7)
x |
Measurement
Over Pin / MOP Spline Wear Inspection |
— | Precision Gage Pins (7)
x |
Measurement
Over Pin / MOP Spline Wear Inspection |
— | Large Rubber Band | MOP Small Gear/
Spline Wear Inspection |
— | Bungee Cord | MOP Large Gear/
Spline Wear Inspection |
— | Temperature Indicating Crayon | Welding Pre-Heat |
File Metric | Threaded Shaft
/ Restore |
|
— | Carbon Arc Gouging Torch | Weld Removal/
Crack Excavation |
— | Plasma Arc Gouging Torch | Weld Removal/
Crack Excavation |
Wheel
(60 Grit) |
Surface
Preparation / De-burring |
|
Thermometer
Infrared -12:1 Ratio |
Temperature
Checks |
|
Tool Tip
101,200 - 202,404 BTU/hr |
Welding Pre-Heat | |
Tip
139,150 - 328,900 BTU/hr |
Welding Pre-Heat | |
Tip
215,050 - 581,900 BTU/hr |
Welding Pre-Heat | |
Tip
404,800 - 822,250 BTU/hr |
Welding Pre-Heat | |
Tip
455,400 - 1,012,000 BTU/hr |
Welding Pre-Heat | |
Handle
Torch |
Welding Pre-Heat | |
Tool
Mixer Oxy-Propane |
Welding Pre-Heat | |
Air Hammer | Weld Removal | |
Breaker Assembly | Weld Removal | |
Portable Angle
Grinder Group |
Welding
Preparation Weld Removal/ Crack Excavation |
|
Wheel Grinder Group | Welding
Preparation Weld Removal/ Crack Excavation |
|
Die Grinder
(Right Angle) |
Surface
Preparation / De-burring |
|
Carbide Bur | Welding
Preparation Weld Removal/ Crack Excavation |
|
Brush
|
Surface
Preparation / De-burring |
|
Tool Group
(Oxy-Propane) |
Welding
Preparation Crack Excavation |
|
Grinding Wheel | Welding Surface
Preparation/ Finish |
|
Blanket
Welding |
Post Welding
Treatment |
|
— | Welding, Cutting, and Gouging Equipment | General Welding |
— | Weld Size Inspection Gauges | Post Weld
Inspection |
— | Arc Spray System | Thermal Spray |
— | HVOF Spray System | Thermal Spray |
— | Adequate Lathe | Machining |
Comparison Gauge (Surface Texture) | Surface Texture
Tester |
|
Indicator
(Profilometer) |
Surface Texture
Tester |
|
Paint
Yellow |
Touch Up | |
Paint
Yellow |
Touch Up | |
— | Reflective Surface for Inspection | Visual Surface
Inspection (VT) |
— (2) | Bright Incandescent Light | Visual Surface
Inspection (VT) |
Magnifying Glass | Visual Surface
Inspection (VT) |
|
Mirror (Telescoping) | Visual Surface
Inspection (VT) |
|
Flashing Lights Conversion Kit | Visual Surface
Inspection (VT) |
|
Light | Visual Surface
Inspection (VT) |
|
Brush
Curved Handle Wire |
General Cleaning/
Liquid Penetrant Testing (PT) |
|
— | Developer | Liquid Penetrant
Testing (PT) |
— | Penetrant | Liquid Penetrant
Testing (PT) |
Paper Towel | Liquid Penetrant
Testing (PT) |
|
— | Solvent Cleaner | General Cleaning/
Liquid Penetrant Testing (PT) |
Crack Detection Kit (Magnetic Particle) | Dry Magnetic
Particle Testing (MT) |
|
Lamp Group
Ultraviolet |
Wet Magnetic
Particle Testing (MT) |
|
— | Spectronics BIB-100P Black Light | Wet Magnetic
Particle Testing (MT) |
— | Magnaflux ZB-100P Black Light | Wet Magnetic
Particle Testing (MT) |
— | Contour Probe DA-200 Magnetic Yoke | Wet Magnetic
Particle Testing (MT) |
— | Parker Research TB-10 Weight Lift Test Bars | Wet Magnetic
Particle Testing (MT) |
— | Magnaflux Magnaglo Fluorescent Particles | Wet Magnetic
Particle Testing (MT) |
— | Paint Pen | Dry Magnetic
Particle Testing (MT) |
— | Sprayer | Wet Magnetic
Particle Testing (MT) |
— | Centrifuge Tube | Wet Magnetic
Particle Testing (MT) |
— | Magnaflux Spotcheck SKC-S Cleaner | Wet Magnetic
Particle Testing (MT) |
— | Gould-Bass DLM-1000 Radiometer | Wet Magnetic
Particle Testing (MT) |
(1) | Refer to PERJ1017Special Publication, "Dealer Service Tools Catalog" for Personal Protective Equipment (PPE) part numbers suitable by geographic location and local safety standards. |
(2) | Refer to Special Publication, PERJ1017, "Dealer Service Tools Catalog" for suitable tooling. |
(3) | Dorsey pn |
(4) | Available in the United States only. |
(5) | Part of Tool Group |
(6) | For use with precision gage pins. |
(7) | Minimum of two are required. |
(8) | Available in Canada, APD, and EAME. |
(9) | Available in North and South America (except Canada). |
Preparation Recommendations
Personal injury can result when using cleaner solvents. To help prevent personal injury, follow the instructions and warnings on the cleaner solvent container before using. |
Personal injury can result from air pressure. Personal injury can result without following proper procedure. When using pressure air, wear a protective face shield and protective clothing. Maximum air pressure at the nozzle must be less than |
Illustration 3 | g06398503 |
Typical example of spindle from the field. |
Note: Clean exterior of the spindle prior to disassembly to minimize cross-contamination.
- Before you inspect the spindle, clean the spindle thoroughly to ensure it is free from rust, oil, burrs, and debris prior to inspection. A surface irregularity can hide the indication of an unacceptable defect.
- Use a proper lifting device to provide safety to the operator. Also, use a proper lifting device to prevent damage to the part when you lift the spindle.
- During cleaning, do not damage machined surfaces.
- Put hydraulic oil on all machined surfaces to prevent rust or corrosion if inspection is not done immediately after cleaning. Carefully store the parts in a clean container.
- Inspect all flange mating surfaces for fretting. Ensure that flange mating surfaces are true and free from raised material resulting from rust, nicks, and dents.
- Use appropriate thread taps to chase all threaded holes.
- Perform a thorough visual inspection for defects and damage.
Show/hide table
Illustration 4 g03794147 Typical burr removal Tooling.
(A) Die Grinder, Right Angle
(B) Wheel Grinder, Group
(C) Conditioning Discs, Disc pad Holder, and Threaded Shaft
(D) Flapper Wheel - Inspect all flange mating surfaces and sealing surfaces. Ensuring that all flange mating surfaces and sealing surfaces are true and free from raised material resulting from rust, nicks, burrs, and dents.
Show/hide table
Illustration 5 g06139437 (G) Typical example of chasing threaded holes. - Remove any broken bolts, use appropriate thread taps to chase all threaded holes.
Show/hide table
Illustration 6 g06139440 Typical example of checking threaded holes using GO/NO-GO thread gauges.
(H) NO-GO Thread Gauge
(J) GO Thread Gauge - Inspect all threaded holes with appropriate GO/NO-GO thread gauges.
Note: NO-GO thread gauge (H) can be screwed into threaded hole no more than two turns. For acceptance of part, GO thread gauge (J) should pass through the entire length of the threaded hole without requiring too much rotational force.
- If NO-GO thread gauge (H) exceeds two turns, then repair threads.
Standardized Parts Marking Procedure
Reference: SEBF8187Reuse and Salvage Guidelines, "Standardized Parts Marking Procedures".
The code is a Cat standard and is used to record the history of a component. The code will identify the number of rebuilds and hours at the time of each rebuild. This information is important and should be considered for any decision to reuse a component.
Ensure that the mark is not covered by a mating part.
The procedure for marking components is a Cat standard. This code is helpful when the machine is sold into a different territory after the first rebuild. During an overhaul, the previous code of a part should never be removed.
Example 1
Illustration 7 | g03856853 |
Typical Example |
Illustration 7 shows code (1-15). The first number (1) indicates that the gear had been rebuilt once. The second number (15) indicates that there were 15,000 hours on the gear at the time of rebuild.
Example 2
Illustration 8 | g03748362 |
Typical Example |
Illustration 8 shows code (1-12) and code (2-10). Code (2-10) represents the information from the second rebuild. The first number (2) indicates that the component had been rebuilt twice. The second number (10) indicates that 10,000 hours accumulated on the component between the first and second rebuild.
Note: Add the first and second rebuild hours to obtain the total number of hours for the component in Illustration 8. In this example, the component has a total of 22,000 hours.
Identification of Spindle Type
Illustration 9 | g03680452 |
Type 1 is a two-piece rear spindle. This spindle is used by the 773 and is also used by some of the first 773B Off-Highway Trucks. |
Illustration 10 | g03680455 |
Type 2 rear spindle that is used by all other Off-Highway Trucks. |
Illustrations 9 and 10, show a typical configuration for a rear wheel spindle. Use the following illustrations to determine the type of spindle.
Inspection
Always use proper lifting devices for the safety of the operator and to prevent damage to the machined surface. Personal Protective Equipment (PPE) should be worn always for the operator's protection.
The spindles and splines must be inspected prior to any repair. These splines are subject to high loads. This makes accurate inspection essential. Splines should be inspected immediately after removal. If the splines are not immediately inspected, hydraulic oil should be applied to each machined surface to prevent rust or corrosion.
- Entire Spindle - Inspect the spindle for cracks. Use either liquid penetrant testing or magnetic particle testing during the inspection process. An internal crack can lead to a failure after a salvage procedure. Refer to Table 15 for crack length acceptability. Refer to Table 23 for welding repair parameters. Refer to Table 13 for spindles that can be salvaged. Refer to Table 14 for spindles that cannot be salvaged. DO NOT install cracked spindles that are not repairable within these guidelines..
- Splines - A cracked spline must not be salvaged. A spline that does not meet the dimensional requirement cannot be salvaged. Because splines transfer high loads, thoroughly inspect each spline for cracks. Measure the average dimension over pins or the average dimension between pins to determine wear. If spline on spindle is cracked, then DO NOT USE AGAIN. To prevent a failure, inspect each of the following critical areas of a spindle.
- Bearing Journals - Measure the surface hardness and the outside diameter for each journal. Bearing journals may be salvaged by using Arc Spray or High Velocity Oxygen Fuel (HVOF).
- Mounting Flange Bolt Holes - These bolt holes may experience damage if bolts are loose during operation. Inspect each bolt hole for deformation. You may salvage a deformed bolt hole by welding the bore and machining the bore.
Always use proper lifting devices for the safety of the operator. Prevent damage to machined surfaces by using the correct lifting equipment.
Wheel Bearing Journals
Illustration 11 | g03680459 |
Typical example of bearing journals |
Bearing journals can be visually inspected with the unaided eye. During an inspection, the best results can be achieved with the use of a magnifying glass and a strong light source. Sunlight is the best light source. Check each component for cracks, bruising, scratching, or spalling. It can also be difficult to distinguish between small scratches and small cracks. In these cases, perform Liquid Penetrant Testing (PT) or Magnetic Particle Testing (MT), refer to the "Crack Detection Methods" section.
If any defects are present, DO NOT USE PART until the component is salvaged. The component can be used after performing the applicable salvage procedure.
Normal Wear
Illustrations 12 through 15 show both inner and outer wheel bearing journal.
Note: The reusability criteria are the same for both inner and outer bearing journals.
Illustration 12 | g03680466 |
The outer bearing journal surface has been laser hardened. Shiny area (A) has been buffed slightly to check the hardness, OK TO USE AGAIN. (A) Shiny Area |
Illustration 13 | g03680470 |
This is a laser hardened inner bearing journal that exhibits normal wear. Once the corrosion has been removed from the surface, then OK TO USE AGAIN. |
Illustration 14 | g03680472 |
This is an inner bearing journal that exhibits normal wear, OK TO USE AGAIN. |
Illustration 15 | g03680474 |
This is an inner bearing journal that exhibits light wear (C) and light pitting (B), OK TO USE AGAIN. (B) Light Pitting (C) Light Wear |
Surface Damage
To recondition the surface of a bearing journal, refer to the "Thermal Spray Procedures for OHT Rear Spindles" section for further information.
Illustration 16 | g03680477 |
This bearing journal surface exhibits smearing damage (C). Before reusing the spindle, buff the surface and verify the dimensions. Refer to Tables 10 and 11. OK TO USE AGAIN (C) Smearing Damage |
Illustration 17 | g03680480 |
Magnified view of Illustration 16. Before you reuse the spindle, buff the surface and verify the dimensions. Refer to Tables 10 and 11. OK TO USE AGAIN (C) Smearing Damage |
Illustration 18 | g03680485 |
This is an outer journal that exhibits bruising (D). A band of corrosion (E) is shown below the journal. DO NOT USE AGAIN Bearing journal may be salvaged using "Thermal Spray Procedures for OHT Rear Spindles". (D) Bruising (E) Band of Corrosion |
Note: If band of corrosion (E) is the only damage, then the spindle may be reused after you buff the corrosive area.
Illustration 19 | g03680490 |
This outer bearing journal exhibits scratching and spalling damage, DO NOT USE AGAIN. Bearing journal may be salvaged using "Thermal Spray Procedures for OHT Rear Spindles". |
Illustration 20 | g03680493 |
Typical example of an outer bearing journal that exhibits heavy damage from spalling, DO NOT USE AGAIN. Bearing journal may be salvaged using ."Thermal Spray Procedures for OHT Rear Spindles". |
Illustration 21 | g03680502 |
Typical example of an outer bearing journal with a layer of thermal spray material missing, DO NOT USE AGAIN. Bearing journal may be salvaged using ."Thermal Spray Procedures for OHT Rear Spindles". |
Illustration 22 | g03680509 |
Typical example of an inner bearing journal that exhibits scratching and spalling damage, DO NOT USE AGAIN. Bearing journal may be salvaged using ."Thermal Spray Procedures for OHT Rear Spindles". |
Illustration 23 | g03680513 |
Typical example of an inner bearing journal with a layer of thermal spray material that has started to flake off. The bond between the bearing journal and the thermal spray material failed., DO NOT USE AGAIN. Bearing journal may be salvaged using "Thermal Spray Procedures for OHT Rear Spindles". |
Illustration 24 | g03680517 |
Typical example of a scalloped edge on the wheel the has caused the inner bearing journal to wear a round groove into the spindle, OK TO USE AGAIN. The depth of the groove must not exceed |
Brake Anchor Flange
Illustration 25 | g06422959 |
Typical example of a spindle that has cracked at the radius near the brake anchor flange. |
Illustration 26 | g06422962 |
Illustration shows a different view of the crack, DO NOT USE AGAIN. |
Porosity of Spindles
Illustration 27 | g06422982 |
(A) Automatic Electronic Traction Aid (AETA) Hole
(1) Lubrication Hole (C) Flange |
Criteria for inspection have been written to assist in determining the acceptability of parts by using visual inspection.
Note: The neutral axis is the axis that runs through Automatic Electronic Traction Aid (AETA) Hole (A) (where present) and lubrication hole (1) (where present). Refer to Illustration 27 for the locations of these holes.
Areas of Inspection
Illustration 28 | g06400404 |
Top view of typical wheel spindle that is separated into four quadrants for inspection. (1) Lubrication Hole (2) Neutral Axis (3) Angle (45°) |
The spindles are divided into four quadrants consisting of nine inspection areas. Refer to Illustrations 28 through 36.
Illustration 29 | g06423003 |
Length (X) is slightly longer than the thickness of the retainer that sets the location of the inner bearing. Refer to Table 4 for parameters of applicable sales models. (C) Flange (X) Length |
Illustration 30 | g06400416 |
Typical example of porous indications. |
Cast Surface
The cast surface shall be free from scale, cracks, hot tears, and any sand that is adhering to the surface.
Area (4)
Illustration 31 | g03680720 |
( 1) Lubrication Hole
(4) Area (X) Length (Table 4) |
Area (4) is the where the retaining seals seats on the spindle with Length (X).
- No visible defects are allowed in Area (4).
Parameters for Acceptable Porosity | |
---|---|
Sales Model | Length (X)(1) |
777 | |
785, 785B, 785C | |
789, 789B, 789C | |
793, 793B, 793C, 793D, 793F | |
797, 797B, 797F | |
(1) | Length (X) is measured from the flange face. |
Area (5)
Illustration 32 | g03680722 |
( 1) Lubrication Hole
(5) Area |
Area (5) is the area around the entire circumference of the outer bearing journal.
- No more than one
3.0 mm (0.12 inch) indication (diameter and depth) is allowed in a2500 mm 2 (3.9 inch 2) . - No more than two
3.0 mm (0.12 inch) indications allowed in Area (5). - No more than 15 total indications are allowed in Area (5).
Area (6)
Illustration 33 | g03680726 |
( 1) Lubrication Hole
(6) Area (X) Length (Table 4) |
Area (6) is the area on side quadrants of the spindle but excluding the inner bearing journal and the outer bearing journal. Area (6) extends from Length (X) to the end of the spindle.
- No more than one
1.5 mm (0.06 inch) indication (diameter and depth) is allowed in a2500 mm 2 (3.9 inch 2) Area (6). - No more than four
1.5 mm (0.06 inch) indications are allowed in Area (6).
Area (7)
Illustration 34 | g03680729 |
( 1) Lubrication Hole
(7) Area (X) Length (Table 4) |
Area (7) is the area around Neutral Axis (2), or the area on both the side quadrants of the spindle but excluding the inner bearing journal and the outer bearing journal. Area (7) extends from Length (X) to the end of the spindle.
- No more than one
3.0 mm (0.12 inch) indication (diameter and depth) is allowed in a2500 mm 2 (3.9 inch 2) Area (7). - No more than four
3.0 mm (0.12 inch) indications are allowed in Area (7).
Area (8)
Illustration 35 | g03680731 |
( 1) Lubrication Hole
(8) Area |
Area (8) is the area on both side quadrants of the inner bearing journal.
- No more than one
1.5 mm (0.06 inch) indication (diameter and depth) is allowed in a2500 mm 2 (3.9 inch 2) Area (8). - No more than three
1.5 mm (0.06 inch) indications are allowed in Area (8). - No more than ten total indications are allowed in Area (8).
Area (9)
Illustration 36 | g03680733 |
( 1) Lubrication Hole
(9) Area |
Area (9) is the area on both top and bottom quadrants of the inner bearing journal.
- No more than one
3.0 mm (0.12 inch) indication (diameter and depth) is allowed in a2500 mm 2 (3.9 inch 2) area. - No more than two
3.0 mm (0.12 inch) indications are allowed in Area (9). - No more than ten total indications are allowed in Area (9).
Splines
Splines can be visually inspected. To ensure the best results, a magnifying glass and a strong light source such as sunlight are recommended. It can also be difficult to distinguish between small scratches and small cracks. If unable to determine scratches from hair line cracks, then perform Liquid Penetrant Testing (PT) or Magnetic Particle Testing (MT).
Ensure to inspect all spline. If damaged spline is found, all spline that mate to it and all splines that are 180° from the damaged spline should be reinspected for possible fatigue from bending. Refer to "Crack Detection Methods" section for Non-Destructive Testing (NDT) procedures.
If spline is damage from misalignment, then DO NOT USE AGAIN. Abnormal wear will not permit full tooth contact thus result in high contact pressures.
Signs of Potential Failure
The key element to analyzing damage on final drive splines is determining if the damage will progress to a failure before the next Planned Component Rebuild (PCR). The application and size of splines are important in determining if the damage will progress.
There are two typical signs of failure:
- Spline wear or fracture from misalignment
- Cracking from fatigue which could lead to fracture
Spline Wear and Misalignment
Spline wear is the result of relative motion between mating spline teeth. High loading, insufficient lubrication, vibration, and abrasive materials may result in wear. Typically, splines can be reused if less than a
There is normally a small amount of relative motion between meshing spline teeth. Uneven contact patterns on the spline teeth are the result of misalignment of one or both of the meshing splines. Splines that are misaligned do not fully engage. This means that only a portion of each tooth is carrying the full load. If the hub and the spindle are not aligned, the spline teeth will not mesh correctly. This situation can place high contact pressures on a portion of the teeth. Misalignment can cause high contact pressure and relative movement. Eventually, spline wear and fretting corrosion will appear as damage on the surface. Misalignment can be identified by the uneven contact pattern on the spline teeth.
If any spline displays uneven contact patterns, be sure to check for misalignment and correct the cause of the problem. The spline could be misaligned, if any of the following are worn or damaged.
- Bearings
- Carrier Bores
- Thrust Faces of Carrier
- Carrier Shafts
Do not reuse a spline with damage from misalignment. Even if you correct the cause of misalignment, the previous abnormal wear will not permit full tooth contact. Correct the cause of misalignment.
Normal Wear
Illustration 37 | g03680739 |
Internal spline with full contact and even wear, OK TO USE THIS PART AGAIN. |
Illustration 38 | g01240365 |
The spline has an external wear step, but the spline meets specifications for reusability. Corrosion from fretting is also apparent. This corrosion is due to lack of lubrication, OK TO USE THIS PART AGAIN. |
Illustration 39 | g03680790 |
The spline in this illustration has an external wear step. This spline is reusable because the measurements are within the required specification. Fretting corrosion is also apparent due to lack of lubrication. Fretting should not progress if the spline is reused, then OK TO USE THIS PART AGAIN |
Wear Steps
Illustration 40 | g06122435 |
Typical example of an external spline with no significant wear (J) steps. (J) Wear |
If spline has no significant wear (J) steps, then OK TO USE AGAIN.
Illustration 41 | g06122438 |
Typical example of an external spline with significant wear (K) steps, DO NOT USE AGAIN. (K) Wear |
If wear steps are found on either external or internal splines, drag a seal pick across the step. If the wear step stops the pick, then DO NOT USE AGAIN.
Illustration 42 | g06319105 |
Check the ends of location of the engagement of the splines. |
If wear steps are found on either external or internal splines, drag a seal pick across the step. If the wear step stops the pick and measures more than
Remember to check the ends of the location of the engagement of the splines. If splines are not worn evenly, DO NOT USE THE PART AGAIN. Check mating spline for alignment.
Corrosion and Pitting
Illustration 43 | g06324680 |
Typical example of corrosion from poor storage techniques, clean inspect for pitting. If excessive pitting, then DO NOT USE THIS PART AGAIN. |
Illustration 44 | g03680797 |
typical example of a spline showing heavy pitting, DO NOT USE THIS PART AGAIN. |
Illustration 45 | g03680798 |
Typical example of a spline exhibiting heavy fretting corrosion, DO NOT USE THIS PART AGAIN. |
Damage to Teeth
Illustration 46 | g06324678 |
Typical example of spline damage from poor handling, but no signs of cracking. Use a polishing stone to smooth any raised material from the indentation, OK TO USE THIS PART AGAIN. |
Illustration 47 | g06324674 |
Typical example of spline damage from poor handling with a sign of cracking. Use a polishing stone to smooth any raised material from the indentation. If evidence of crack after removal of raised material, then DO NOT USE THIS PART AGAIN. |
Illustration 48 | g03680795 |
A spline is cracked in the area of the root and the crack has progressed into the adjacent splines, DO NOT USE THIS PART AGAIN. |
Crack from Fatigue on Spindles
Operational loads create tensile stress in the fillet area on the loaded side of a tooth. With enough high loads and cycles, these stresses can cause fatigue cracks. A fatigue crack will develop until the tooth weakens enough to separate from the parent metal.
Numerous broken spline teeth may be the result of failure from bending fatigue. The operational loads create tensile stress in the fillet on the loaded side of the tooth. With enough high loads and cycles, these stresses can cause cracks from fatigue. A crack from fatigue could cause a tooth to separate from the parent metal. Cracking can also occur between the root of the tooth and a bolt hole or inside diameter of the part.
Illustration 49 | g06324684 |
Typical example of a crack extending from the spline into the bolt hole. The bolt hole is weakened and premature failure will result, DO NOT USE THIS PART AGAIN. |
Illustration 50 | g06324686 |
Typical example of a crack in the root of the spline tooth, DO NOT USE THIS PART AGAIN. |
Measurement Techniques
NOTICE |
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Precise measurements shall be made when the component and measurement equipment are at |
Measurement Tooling Calibration
Outside Micrometers
Illustration 51 | g06208395 |
Typical example of calibrating outside micrometer (A). (A) Outside Micrometer |
Measurement Tooling include precision inside and outside diameter micrometers capable of measuring four decimal places in inches or three decimal places in millimeters. Measurement Tooling should be calibrated using gauge blocks certified to a national standard such as the National Institute of Standards and Technology (NIST).
Dorsey Carbon Fiber Snap Gages
Dorsey Carbon Fiber Snap Gages | |
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Part Number | Gage Size To Check |
90141-2 | |
92268-2 | |
92270-2 | |
92531-2 | |
92718-2 | |
Carbon fiber snap gages are available for measuring bearing journal diameters, refer to Table 5 for the following sizes.
Journal Diameters
Illustration 52 | g06318222 |
Typical example of measuring an Outside Diameter (OD) Dimension of a spindle. (C) Indicates the diameter of the shaft. (D) Indicates the overall measurable length of the shaft journal. |
Take measurements at locations (C1), (C2), and (C3).
Then take measurements at locations (C4), (C5), and (C6).
To ensure adequate life of the components, this document contains precise tolerances for measurements taken on various features. Ensure that several sample measurements are taken at different locations on the same feature. Measure diameters of journals in six places to identify tapered and or oval conditions. Refer to Illustration 52.
Spline Wear Measurement Procedures
This section provides the procedures that are necessary for you to measure both internal splines and external splines. This section will help you to calculate these measurements. Then, these results can be used to determine reusability of both internal splines and external splines on all Off-Highway Trucks.
- For the measurement of an external spline, calculate the average for the three measurements over pins. For each of the three dimensions, measure the highest external point over two pins that are 180° opposite of each other. Use the following procedure to determine the maximum allowable spline wear.
- Average the three dimensions to produce the average dimension over pins.
- For the measurement of an internal spline, calculate the average for the three measurements between pins. For each measurement, take the closest internal point between two pins that are 180° opposite of each other. Use the following procedure to determine the maximum allowable spline wear.
Gage Pins
For this procedure, each type of spline will require the use of a specific gage pin set. Refer to Table 12 for gage pin dimensions. The gage pins are readily available commercially but if the gage pins are unavailable through your ordering system machine each pin for the specific pin set. Care must be taken to precisely machine these gage pins to specification due to the close tolerances of the gage pin diameters. If these gage pins are to be made, the use of 52100 alloy steel is recommended. These gage pins are Class ZZ and have an allowed deviation of 0.00508 mm (0.00020 inch), geometry of 0.00254 mm (0.00010 inch), and a surface texture of 0.2540 μm (10.000 μinch) Ra.
Methods of Securing Gage Pins
Illustration 53 | g06075262 |
Typical example of MOP. (N) Rubber Band (P) Gage Pins |
Note: Rubber band (N) can be used to secure gage pins (P) in place when taking measurements of external splines. Refer to Illustration 53.
Illustration 54 | g06124082 |
Typical example of a magnetizer/ demagnetizer. |
NOTICE |
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If gage pins are magnetized, then demagnetize after use. When a gage pin is magnetized, cuttings and iron powder will easily stick to the surface, thus precipitating wear. |
Gage pins can be magnetized to aid in taking measurements between or over gage pins. Ensure that gage pins are demagnetized after use and stored properly.
Illustration 55 | g06075285 |
Typical example of taking a Measurement Over Pins (MOP). (R) Gage Pin (S) Magnet |
Note: Magnet (S) is another method that can be used to keep gage pins (R) in place when taking measurements. Refer to Illustration 55.
External Spline
Illustration 56 | g06321303 |
Typical wear step on an external spline. |
Illustration 57 | g06322365 |
Typical example of using a straight edge to measure a wear step on a spline tooth. |
If possible, use a straight edge and a feeler gauge to measure questionable spline wear.
Illustration 58 | g01716121 |
Typical example of a wear step. A |
Illustration 59 | g06075290 |
Typical example of taking a Measurement Over Pins (MOP). |
Illustration 60 | g06181327 |
(L) 1, (L) 2, and (L) 3 Measurement Locations |
The location of gage pins at 60° intervals is critical to the formula. These three locations will provide information about the wear of the part. Refer to Illustration 60.
Note: For odd splines take measurement as close to 180° from each gage pin as possible.
Place gage pins at 60° intervals on the spline. Take the measurements over gage pins that are located approximately 180° away from each other.
A micrometer must be positioned to measure the highest external points on the gage pins. This procedure will provide the measurement of the wear of the spline. The gage pin diameter for each individual part is determined by the size and pitch of the spline. Calculate the average from the values taken. The difference between the measurements will determine if there is an out of round condition caused by poor load distribution on the splines.
Steps 1 through 4 demonstrate an example of the process to calculation external spline roundness. Provided is an example of performing spline reusability calculations.
NOTICE |
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The spline must pass the roundness tests by meeting the reusability specification measurement over gage pins and the maximum difference between the high and low measurements to be reused again. |
- Take measurements at locations (L) 1, (L) 2, and (L) 3 over gage pins. Taken measurements are recorded in Table 6.
Show/hide table
Table 6 External Spline
Example of Recording 3 Measurements TakenLocation Measurements Taken L1 Ø 299.000 mm (11.7716 inch) L2 Ø 298.900 mm (11.7677 inch) L3 Ø 298.800 mm (11.7638 inch) - Add the measurements together to calculate the sum. The sum of the three measurements is
896.700 mm (35.3031 inch) .Show/hide tableTable 7 External Spline
Example of Calculating Sum of 3 Measurements TakenMeasurement
LocationsCalculation SUM Total = L1, L2, and L3 L1 + L2 + L3 896.700 mm (35.3031 inch) - Divide the sum of the measurements taken by 3 to calculate the average. The calculated average of
298.900 mm (11.7677 inch) is greater than the reusability specification of298.781 mm (11.7630 inch) . In this example the external spline is within the reusability specification and therefore passes this test, proceed to Step 4.If the external spline is less than the reusability specification, then DO NOT USE THE PART AGAIN.
Show/hide tableTable 8 External Spline
Example of Calculating the Average of 3 Measurements TakenLocation Calculations Results L1, L2, and L3 (L1 + L2 + L3) / 3
= AvgØ 298.900 mm (11.7677 inch) Refer to Specifications in Table 12. Reusability
SpecificationØ 298.781 mm (11.7630 inch) Avg Specification Avg < Reusability Specification = Fail
Avg > Reusability Specification = PassAvg = Ø 298.900 mm (11.7677 inch) > than Reusability Specification ofØ 298.781 mm (11.7630 inch)
Pass - The difference between the high measurement and the low measurement determines if the spline is round. Out-of-round or ovality can cause uneven load distribution on the splines. Calculate the difference between the high and the low measurement by subtracting the high measurement of
Ø 299.000 mm (11.7716 inch) from the low measurement ofØ 298.800 mm (11.7638 inch) . The difference between the high and low measurement determine if the spindle can be reused. The difference in this example is0.200 mm (0.0079 inch) .Maximum difference between the high measurement and the low measurement allowance of
0.30 mm (0.012 inch) and the actual difference of0.200 mm (0.0079 inch) is less than the allowable maximum difference.If the maximum difference between the high measurement and the low measurement is greater than
0.30 mm (0.012 inch) the external spline is considered to be out-of-round or oval shaped and not reusable, DO NOT USE THE PART AGAIN.Show/hide tableTable 9 External Spline
Example of Determining the Difference from the 3 Measurements TakenLocation Calculations Results L1 High Ø 299.000 mm (11.7716 inch) L2 Mid Ø 298.900 mm (11.7677 inch) L3 Low Ø 298.800 mm (11.7638 inch) L1 - L3 High and Low
Difference =0.200 mm (0.0079 inch) Refer to Specifications in 12. Maximum
Difference
Allowance0.30 mm (0.012 inch) Actual Difference (H - L) Maximum Difference Allowance Actual Difference > Maximum Difference Allowance = Fail
Actual Difference < Maximum Difference Allowance = PassActual Difference = 0.200 mm (0.0079 inch) < than Maximum Difference Allowance of0.30 mm (0.012 inch)
Pass
Spindle Bearing Journal Dimensions and Tolerances
Measure the diameter of the spindle at each bearing journal. Refer to Table 10, or Table 11 for this dimension. The acceptable tolerance for reusability of bearing journals is “+
Do not confuse this tolerance for reusability with the acceptable machining tolerance for a spindle which has been salvaged.
Type 1 Rear Spindle Assembly
If the following areas on a Type 1 spindle show significant wear, thermal spray can be used for the repair of bearing journal surfaces on spindles. Both Arc Spray and HVOF are acceptable processes for this rework.
Note: Only Caterpillar dealers may utilize applications for Thermal Spray. The processes must be carried out within the facilities of the dealership. The dealership must maintain a clean environment. The dealership must always use the correct equipment for all processes in each Thermal Spray Application.
Illustration 61 | g06413059 |
Type 1 spindle is shown here. Refer to Table 10 for dimensions. |
- Bearing Journals Diameter (A)
- Bearing Journals Diameter (B)
- Seal area diameter (C)
- Length (D)
- Face (E)
- Diameter (F)
- Diameter (H)
- Length (J)
- Diameter (X)
- Face (Y)
After the repair is complete, mount the spindle assembly on a lathe. Zero the part on diameter (X) and face (Y).
Diameters (A), (B), and (C) must be concentric within
Dimensions and Tolerances for Type 1 Spindles | ||||||||
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Part
Number |
Diameters
(A & B) Surface Texture - |
Diameter (C) | Length (D) | Diameter (F) | Diameter (H) | Length (J) | Diameter (X) | Diameter for the Mounting Flange Bolt Hole |
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Type 2 Rear Spindle Assembly
If the following areas on a Type 2 spindle show significant wear, thermal spray can be used for the repair of bearing journal surfaces on spindles. Both Arc Spray and HVOF are acceptable processes for this rework.
Note: Only Caterpillar dealers may utilize applications for Thermal Spray. The processes must be carried out within the facilities of the dealership. The dealership must maintain a clean environment. The dealership must always use the correct equipment for all processes in each Thermal Spray Application.
Illustration 62 | g06413073 |
Type 2 spindles are shown here. Refer to Table 11 for dimensions. |
- Bearing Journals Diameter (A)
- Bearing Journals Diameter (B)
- Length (N)
- Chamfer (P) is 15°
- Diameter (X)
- Brake Flange Face (Y)
After the repair is complete, mount the spindle assembly on a lathe. Zero the part on diameter (X) and face (Y).
Diameters (A), and (B), must be concentric within
Dimensions and Tolerances for Type 2 Spindles (1) | Record Actual Dimensions
Refer to the "Journal Diameters" section for the proper techniques and number of measurements to be taken. |
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Part
Number |
Bearing Journal Diameter
(A) Surface Texture - |
Bearing Journal Diameter
(B) Surface Texture - |
Length
(N) |
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(1) | Note: The most current part number is identified in bold font when multiple part numbers are in a cell. |
Spindle Spline Dimensions and Tolerances
Illustration 63 | g06321299 |
Typical example of taking a Measurement Over Pins (MOP) (A) of spindle spline. (A) Measurement Over Pins (MOP) |
Spindle External Spline Dimensions and Tolerances (1) | Record Actual Dimensions
Refer to the "Spline Wear Measurement Procedures" section for the proper techniques and number of measurements to be taken. |
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Part Number | Gage Pin
Diameter |
Original Specification
Measurement Over Gage Pins |
Reusability Specification
Measurement Over Gage Pins |
Maximum Difference
High and Low Measurement |
Measurement (A) |
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(1) | Note: The most current part number is identified in bold font when multiple part numbers are in a cell. |
Crack Inspection
Spindles That Can Be Salvaged |
---|
Spindle Part Number |
Spindles That Can NOT Be Salvaged |
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Spindle Part Number |
(1) | This spindle requires a special salvage process and should be returned to Reman if the core is acceptable |
Maximum Allowable Crack Length and Depth | ||
---|---|---|
Sales Model | Surface Crack Length | Crack Depth |
777 | |
|
785 | |
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789 | |
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793 | |
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797 | |
|
Use the following criteria to determine if the cracks can be repaired.
- Cracks must not extend through the entire section. Cracks must not be deeper than the dimensions in Table 15.
- For maximum allowable crack length refer to Table 15.
- Do not weld cracks in designated areas in Illustration 66 ,67, and 68.
Multiple Crack Criteria
Illustration 64 | g03681149 |
Collinear if less than 45° angle. (A) 45°. |
Two cracks close together are considered to be collinear (along the same line) if the angle between the two cracks is less than 45°.
Illustration 65 | g03681152 |
Multiple Crack Criteria |
- Example (1) Collinear within
25 mm (0.98 inch) diameter circle, treat as one crack. - Example (2) Collinear outside
25 mm (0.98 inch) diameter circle, treat as two cracks. - Example (3) Non-Collinear within
25 mm (0.98 inch) diameter circle, treat as two cracks. - Example (4) Mixture of Collinear and Non-Collinear within
25 mm (0.98 inch) diameter circle. Treat the two collinear cracks as one crack. Treat the one non-collinear crack as one crack.
770-772, 773, 775, 777, and 785 Rear Spindle Crack Allowances
Weld repair is not allowed in Area (X) for the following models 770-772, 773, 775, 777, and 785. Crack allowances are not yet available for these models.
Illustration 66 | g03681154 |
Area (X) includes the small radius inboard of the brake mounting flange or spline. |
789, 793, and 797 Rear Spindle Crack Allowances
Illustration 67 | g03681158 |
Typical view of a rear spindle with a spline style brake mounting. Inspection Zones: (A) ( B), (C), and (F) No Weld Zones: Area (X) ( A) Zone A (B) Zone B (C) Zone C (F) Zone F (Mounting Flange) (X) Area X |
Illustration 68 | g03681165 |
Typical view of a rear spindle with a flange style brake mounting Inspection Zones: (A) ( B), (C), and (F) No Weld Zones: Area (X) ( A) Zone A (B) Zone B (C) Zone C (F) Zone F (mounting flange) (X) Area X |
For 789 spindles, minor grinding to reduce or remove cracks is acceptable in Zone (A) (between the journals), Zone (B), and Zone (C). Maximum grind depth without subsequent weld repair is
The spindle should be returned to Cat Reman for core credit if one or more of the following conditions apply:
- A crack remains after excavating
25 mm (1.00 inch) from original cast surface. - Crack in either Zone (B) or Zone (C) is greater than
125 mm (4.921 inch) in length at maximum excavation depth of25 mm (1.00 inch.) - Zone (F) repair is required beyond what is allowed. Refer to Table 16 for more information on mounting flange.
Note: Zone (F): Minor cracks up to
Sales Model | Measured Pre-Excavation
Excavation Depth Zone E Maximum |
Measured Pre-Excavation
Repairable Crack Length Zone F Maximum |
Measured Pre-Excavation
Excavation Depth Zone G Maximum |
Measured Pre-Excavation
Excavation Depth Zone H Maximum |
Excavation and Weld Repair Zone J
Maximum Distance from the Edge of Mounting holes. (1) |
---|---|---|---|---|---|
789 | |
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793 | |
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797 | |
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(1) | The ground weld repairs are to match original surfaces, avoiding removal of material outside of limits. Radius in corner must be restored to the original size. |
Note: Multiple cracks and collinear cracks are special cases. Refer to Section "Multiple Crack Criteria".
789 Rear Spindle Crack Allowance for Zone A
- If greater than
16 mm (0.63 inch) in length, grind and blend to3.0 mm (0.11811 inch) in depth (maximum), then if less than16. mm (0.62992 inch) in length, OK TO USE AGAIN.
789 Rear Spindle Crack Allowance Zone B and Zone C
- No repair required for cracks
16 mm (0.60 inch) in length or less in Zone (B) or Zone (C). - Repair all cracks in Zone (B) and Zone (C) greater than
16 mm (0.60 inch) in length. Weld repair is required if crack is greater than16 mm (0.60 inch) in length after grinding to a maximum of9 mm (0.35 inch) in depth from the original surface. Refer to the "Special Crack Excavation for Zone F on 789, 793, and 797 Spindles" section.
793 Rear Spindle Crack Allowances
For 793 spindles, minor grinding to reduce or remove cracks is acceptable in Zone (A) (between the journals), Zone (B), and Zone (C). Maximum grind depth without subsequent weld repair is
The spindle should be returned to Cat Reman for core credit if one or more of the following conditions apply:
- A crack remains after excavating
25 mm (1.00 inch) from original cast surface. - Crack in either Zone (B) or Zone (C) is greater than
125 mm (4.921 inch) in length at maximum excavation depth of25 mm (1.00 inch.) - Zone (F) repair is required beyond what is allowed. Refer to Table 16 for more information on mounting flange.
Note: Zone (F): Minor cracks up to
Note: Multiple cracks and collinear cracks are special cases. Refer to Multiple Crack Criteria s Section."Multiple Crack Criteria".
793 Rear Spindle Crack Allowance in Zone A
- Grind and blend up to 3 mm in the depth. If remaining crack is less than 3 mm, then OK TO USE AGAIN.
Cracks in the lube slot can be removed with a proper mill cutter. Slot may be machined oversize up to
20 mm (0.80 inch) wide and13 mm (0.50 inch) deep to remove cracks. Chamfer or debur edges.Note: If the cracks remain after machining slot to maximum size, return spindle to Cat Reman.
Note: Spindles with cracks extending through any edge to the bearing journal diameter must be returned to Cat Reman for repair.
Illustration 69 | g03681170 |
Typical view of the lube slot located in Zone (A) on the spindle. |
793 Rear Spindle Crack Allowance in Zone B and Zone C
Illustration 70 | g03681172 |
Top view looking down on the spindle (X) Neutral Axis through Lube Hole (B1) ( C1) High Load Zone (B2) ( C2) Low Load Zone |
- Repair all cracks in Zone (B1) and Zone (C1). No weld repair is required if the crack can be removed by grinding up to
3 mm (0.10 inch) in depth from the original surface. Blend smooth after grind repair. - No repair is required for cracks
16 mm (0.60 inch) in length or less in Zone (B2) and Zone (C2).
Note: Zone (B1) and Zone (C1) are defined as the area between mounting holes 3 and 20 and mounting holes 28 and 45. Zone (B2) and Area (C2) are defined as the area between mounting holes 19 and 29 and mounting holes 3 and 44. Refer to Illustration 70.
797 Rear Spindle Crack Allowances
For 797 spindles, minor grinding to reduce or remove cracks is acceptable in Zone (A) (between the journals), Zone (B), and Zone (C). Maximum grind depth without subsequent weld repair is
The spindle should be returned to Cat Reman for core credit if one or more of the following conditions apply:
- A crack remains after excavating
40 mm (1.60 inch) from original cast surface - Crack in either Zone (B) or Zone (C) is greater than
150 mm (6.00 inch) in length, at maximum excavation depth of40 mm (1.60 inch) - Zone (F) repair is required beyond what is allowed. Refer to Table 16 for more information on mounting flange.
Note: Zone (F): Minor cracks up to
Note: Multiple cracks and collinear cracks are special cases. Refer to the "Multiple Crack Criteria" section.
797 Rear Spindle Crack Allowance for Zone A
- If greater than
16 mm (0.63 inch) in length, grind and blend to3.0 mm (0.11811 inch) in depth (maximum), and if less than16 mm (0.63 inch) in length, then OK TO USE AGAIN.
797 Rear Spindle Crack Allowance Zone B and Zone C
- No repair required for cracks
16 mm (0.60 inch) in length or less in Zone (B) or Zone (C). - Repair all cracks in Zone (B) and Zone (C) greater than
16 mm (0.60 inch) in length. Weld repair is required if crack is greater than16 mm (0.60 inch) in length after grinding to a maximum of9 mm (0.35 inch) in depth from the original surface. Refer to the "Special Crack Excavation for Zone F on 789, 793, and 797 Spindles" section.
Crack Excavation
Once a crack has been detected the crack shall be removed by grinding, air carbon arc gouging, or machining. Cavities which have been gouged shall be chipped or ground to remove the gouging slag. Grind smooth all uneven areas caused by gouging which present pockets to trap slag. Non-Destructive Testing (NDT) shall be used to ensure that cracks have been removed, refer to the "Dry Magnetic Particle Testing (MT)" section.
Note: Cover all exposed machined surfaces before beginning crack excavation.
Air Carbon-Arc Gouging
Illustration 71 | g06085892 |
Air Carbon-Arc Gouging Equipment (A) Air Compressor (B) Power Source (C) Air and Power Connection (D) Hand Held Electrode Holder (E) Arc Gouging Electrode (F) Air Stream (G) Molten Material Removed from Work Piece (H) Work Piece (J) Work Lead |
In many situations, the use of air-carbon arc gouging for the removal of defects is the best option. A significant advantage to the use of air-carbon arc gouging is the amount of metal which can be quickly removed. This process can also be used in locations which are not accessible to mechanical metal removers. Follow Steps 1 through 4 to obtain good results during the removal of defects with the air-carbon arc process:
- All materials to be air-carbon arc gouged shall be preheated prior to gouging to
21 °C (70.0 °F) . - The current ranges in Table 17 shall be used depending upon the carbon electrode diameter. A minimum open circuit voltage of 60 Volts shall be available.
Show/hide table
Table 17 Air Carbon-Arc Gouging Information Electrode
DiameterCurrent Range
(Amps, DC+)Ø 6 mm (1/4 inch) 300-400 A Ø 8 mm (5/16 inch) 350-450 A Ø 10 mm (3/8 inch) 450-600 A Ø 12 mm (1/2 inch) 800-1000 A Show/hide tableIllustration 72 g06045852 Gouging Operation
(K)25.4 mm (1.00 inch)
(L)50.8 mm (2.00 inch)
(M)6.35 mm (0.250 inch)
(N) Plane of Crack
(P) Layers - To prevent cracks from "running" during the air-carbon arc gouging operation, following Steps a through c for crack removal.
- Starting in sound base metal approximately
25 mm (1 inch) from each end of the crack, gouge toward the center of the crack. The extent of metal removed should be approximately that shown in Illustration 72. - Remove the remainder of the crack between the two gouged end areas to the same depth as the initial gouges.
- Repeat Steps 3a and 3b in layers approximately
6.35 mm (0.250 inch) deep until the crack is removed. Ensure to widen the groove toward the top surface as the depth increases per end view in Illustration 72.
- Starting in sound base metal approximately
- MT to ensure that full crack is removed.
Weld Groove Preparation
Illustration 73 | g03681122 |
Angle (Z) should be 30° for a crack that has a depth up to |
Note: Be sure that the temperature of the base metal is at least
- After the crack has been removed, prepare the weld groove. Use a grinder to create an angle on the sidewall of the gouged section.
Perform one of the following operations.
- Any crack that has a depth of
38 mm (1.5 inch) or less is a small crack. To prepare the groove for a small crack, grind a 30° angle on the sidewall. - Any crack that has a depth that is between
38 mm (1.5 inch) and51 mm (2 inch) is a large crack. To prepare the groove for a large crack, grind a 45° angle on the sidewall.
- Any crack that has a depth of
- If necessary, use a grinder to dress the sides and the bottom of the weld joint. The weld must be free from carbon and rough edges. Ensure that the weld has a proper opening. Surfaces to be welded should be free from all rust, grease, oil, paint, or any other possible sources of moisture.
Special Crack Excavation for Zone F on 789, 793, and 797 Spindles
Note: Verify that the casting part number is listed in Table 13. Do Not proceed if the casting part number to be salvaged is not listed.
- Verify that casting has been properly inspected by a qualified NDT specialist.
Use wet magnetic particle testing for inspecting cracks before, during and after excavation to ensure that the crack has been fully removed.
Show/hide tableIllustration 74 g06424189 Spindle Crack Map
(D) Lube Hole or Lube Slot (aligned with 6:00 o'clock position) - Locate cracks. Refer to Illustration 74 for Zone locations.
Note: The 6:00 o'clock position is directly in line with the lube hole (D).
- The spindle should be at ambient temperature of at least
20° C (68° F) , before grinding or excavating the crack.Show/hide tableIllustration 75 g03681876 Typical view of a 4.5 inch grinder. Show/hide tableIllustration 76 g03681881 Typical view of a deburring tool.
The guard has been removed for illustration purposes. - A deburring tool or a grinder is the only method approved for crack removal and excavation. Refer to Illustrations 75 and 76.
Note: Always operate tooling using Personal Protection Equipment (PPE) and safety guards.
- Fully remove cracks or reduce cracks to an acceptable length, depending on location. All weld repairs require complete removal of the crack, verified using the wet magnetic particle inspection process, before proceeding. Maximum weld repairable depth and length apply.
- Once all the cracks are removed, use the wet magnetic particle testing process to ensure that cracks are fully removed before proceeding.
Illustration 77 | g03681896 |
View of cracks before blending |
Illustration 78 | g03681901 |
View of cracks after blending |
Illustration 79 | g03681905 |
Excavation limits for 789, 793, 797, refer to Table 16 for the dimensions. |
Illustration 80 | g03681911 |
Edge of the mounting holes for 789, 793, 797, refer to Table 16 for the dimensions. |
Document the work order number, casting numeral code, serial number, spindle service hours, OR sequence number (if applicable), and the OR stamped numeral code in Table 18.
Inspection Checklist | |
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Work Order Number | |
Truck Serial Number | |
Truck SMU, Hours | |
Cast Part Number | |
Cast Numeral Code | |
Pour Date (Refer to Table 19 Numeral Code Lookup) | |
Cast Serial Number | |
Spindle Service Hours | |
OR Stamped Part Number (If Applicable) | |
OR Stamped Sequence Number (If Applicable) |
Numerical Code Lookup | |
---|---|
N | 0 |
U | 1 |
M | 2 |
E | 3 |
R | 4 |
A | 5 |
L | 6 |
K | 7 |
O | 8 |
D | 9 |
Record details of all cracks greater than
Illustration 81 | g06424189 |
Spindle Crack Map (D) Lube Hole or Lube Slot (aligned with 6:00 o'clock position |
Weld # | Pre-Inspection | Weld Prep | Weld Process | Zone | Radial Ref. | Verticle Measure Ref. | Angle Off Horizontal | Length of Weld | Depth of Weld | Date |
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Condition | 793 Inspection Results (Pass/Fail) | ||||
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A | B1 | B2 | C1 | C2 | |
No Repair Required | |||||
Grind | |||||
Grind and Weld | |||||
Remove From Service |
Condition | 789 / 797 Inspection Results (Pass/Fail) | ||
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A | B | C | |
No Repair Required | |||
Grind | |||
Grind and Weld | |||
Remove From Service |
Salvage Welding
Personal injury or death can result from fumes, gases and ultraviolet rays from the weld arc. Welding can cause fumes, burn skin and produce ultraviolet rays. Keep your head out of the fumes. Use ventilation, exhaust at the arc, or both, to keep fumes and gases from your breathing area. Wear eye, ear and body protection before working. Protect yourself and others; read and understand this warning. Fumes and gases can be dangerous to your health. Ultraviolet rays from the weld arc can injure eyes and burn skin. Electric shock can cause death. Read and understand the manufacturer's instructions and your employer's safety practices. Do not touch live electrical parts. See "American National Standard Z49.1, Safety in Welding and Cutting" published by the American Welding Society. American Welding Society2501 N.W. 7th Street Miami, Florida 33125 See "OSHA Safety and Health Standards, 29 CFR 1910", available from U.S. Department of Labor. U.S. Department of LaborWashington, D.C. 20210 |
NOTICE |
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Weld repair should be done cautiously in certain locations as the heat can cause distortion in the case and pull components out of alignment. Generally, the larger the crack and weld repair, the more chance for developing distortion. |
Weld repairs that do not get machined should be ground flush or shaped to match the profile of the surrounding material of gear case. There should be no visible defects present such as rollover, undercut, porosity, or slag inclusions. Ensure that each repair is inspected after the metal cools using either Liquid Penetrant Testing (PT) or Dry Magnetic Particle Testing (MT) methods. Refer to the "Crack Detection Methods" section.
Welder Qualifications
Note: Personal breathing protection should be worn by the personnel that are welding. Personal breathing protection will prevent fumes from entering the lungs of the person that is welding. Use a respirator for breathing protection.
Welders must be qualified for the appropriate type of weld that is being performed:
- Shielded Metal Arc Welding (SMAW)
- Flux Cored Arc Welding (FCAW)
- Gas Metal Arc Welding (GMAW)
Welders must be qualified for the appropriate position of weld that is being performed. Refer to AWS Specifications D1.1 and D14.3 or comparable standards for information that regards qualification requirements. The welders must have used the process at some time within the last 6 months. The welders must complete the process of certification if the welders have not used the welding processes for 6 months. The welding operator must hold a current certification for this process. The operator must wear the appropriate equipment. The operator must also install all appropriate equipment. All equipment must maintain the amount of fumes, heat, and ultraviolet radiation at a safe limit.
References:
- SEBD0512Reuse and Salvage Guidelines, "Caterpillar Service Welding Guide"
- ANSI/ AWS D1.1, D14.3
- Caterpillar Manufacturing Practice MC1000-105
Welding Materials and Specifications
Process | Units | FCAW | GMAW | SMAW |
Filler/Weldign Materials, Gas/Flux | ||||
Pass or layer Weld | All | All | All | |
Class | E90T1-D3C | ER80S/90S-D2 | E10018-D2 (1)
E11018-D2 |
|
AWS Standard | A5.29 | A5.28 | A5.5 | |
Polarity | DCEP | DCEP | DCEP | |
Electrode Size Options | ||||
Diameter | inch | 1/16 | 0.045 | 1/8 |
Amps | amp | 230-250 | 275-300 | 100-120 |
Volts | volt | 28-30 | 27-30 | N/A |
Travel Speed | inch/min | N/A | N/A | N/A |
Diameter Alternate | inch | 3/32 | 0.052 | 3/16 |
Amps | amp | 230-250 | 275-300 | N/A |
Volts | volt | 28-30 | 27-30 | N/A |
Travel Speed | inch/min | NA | NA | N/A |
Shielding Gas (Recommended) | 100% CO2 | Ar 90%- CO2 10% | N/A | |
Shielding Gas (Alternate) | Ar 90%- CO2 10% | Ar 75%- CO2 25% | N/A | |
Flow Rate | L/min
CFH |
15-17
40-45 |
15-17
40-45 |
N/A
N/A |
Electrode Stickout | inch | 1/2-3/4 | 1/2-3/4 | N/A |
Joint | ||||
Joint Design | Single V | |||
Root Opening | 0 | |||
Root Face | 0 | |||
Buttering | N/A | |||
Back Gouge Required | No | |||
Backing Material | N/A | |||
Position | ||||
Position of Groove | 1G + 2G | |||
Vertical Progression | N/A | |||
Preheat | ||||
Preheat Temperature | °C | 200 °C | ||
Method | Flame or Furnace (if available) | |||
Interpass Temperature | °C | 200°C min. | ||
Post Weld Heat Treatment | ||||
Heating Rate | °C/hr | 200 °C | ||
Hold Temperature / Time | N/A | |||
Cooling Rate | N/A | |||
Comments | Cover with a fire blanket and allow to cool | |||
Weld Technique | ||||
Bead | Stringer | |||
Initial / Interpass Cleaning | Chip, Needle Peen, or Wire brush | |||
Back Gouge Method | NA | |||
Comments | De-slag and or clean Every Pass | |||
Inspection | ||||
Method | Visual, Wet Magnetic Particle |
(1) | The E10018-D2 is a low hydrogen electrode. The electrode must be stored in an electrode oven at a temperature of |
Equipment
Illustration 82 | g06123326 |
Flux-Cored Arc Welding (FCAW) Equipment (A) Welding Electrode Spool (B) Wire Feeder (C) Gas Line-Out (D) Weld Gun Control Cable (E) Controller (F) Gas Line-In (G) Shielding Gas Tank (H) Power Cable (J) Ground Cable (K) Work Piece (L) Weld Gun |
The flux cored arc welding - CO2 shielded process requires a power source, wire feeder control, gun, and a system for supplying a shielding gas. A constant potential type power source is required to obtain the maximum efficiency from the flux cored arc welding process. This type of power source automatically supplies the correct amperage to maintain constant arc voltage. Most constant potential welding machines are rated 100% duty cycle at rated current. The power source should be rated equal to or above the highest volts and amperes specified by any welding procedure for which it is to be used. This practice provides a safety margin when the welding machines are operated for short periods of time at currents above the rated capacity. The main advantage provided by constant potential welding machines is the simplicity of the welding operation. The wire feed speed is adjusted to give the desired welding amperage which is automatically provided by the constant potential welding machine.
FCAW Consumables
The consumable welding materials involved in flux cored arc welding - CO2 shielded, are a flux cored fabricated continuous wire type electrode and the CO2 shielding gas.
The selection of the filler metal (electrode) is based on the composition of the base metal, the metal thickness, and type of joint, joint geometry, position of welding and the service requirements of the weldment. Refer to the weld parameter table located in the specific section to be welded for electrode specification and size.
Flux Cored Arc Welding (FCAW) electrodes are made in types to match practically all mild and low alloy steels. FCAW electrodes are available in
Carbon Dioxide Shielding Gas
Carbon dioxide used with the flux cored arc welding process must be "welding grade" because moisture in the gas will produce porous welds. "Welding grade" CO2 has a dew point of
Shielded Metal Arc Welding (SMAW)
SMAW Consumables (Electrodes)
The electrode is the only consumable involved in shielded metal arc welding. The selection of the electrode (filler metal) is based on the condition and composition of the base metal, the metal thickness, and type of joint, joint geometry, position of welding and the service requirements of the weldment.
Equipment
Illustration 83 | g06123333 |
SMAW Equipment (M) Electrode Holder (N) Electrode Cable (P) Power Source (R) Ground Cable (S) Ground Cable or Lug Attached to Work Piece (T) Work Piece |
The Shielded Metal Arc Welding (SMAW) process requires a power source, lead and ground cables, a ground clamp and electrode holder. The equipment is relatively simple and low in cost compared to most of the other welding processes. The SMAW process requires one of the following types of power sources.
- Direct Current (DC) Supply
- Alternating Current (AC) Supply
- Alternating Current (AC)/Direct Current (DC) Supply
Either type of power source is adequate for general-purpose welding. Direct current is often preferred for light articulate and/or out-of position welding because direct current produces a slightly smoother arc. Slightly higher deposition rates are possible with direct current, but this advantage is often offset by the disadvantage of greater arc blow.
Most electrodes are designed for DC or AC, although some types are designed for DC only.
Welding Preparation / Area Preparation
The area to be welded shall be clean, dry, and free of the following contaminants:
- Oil
- Grease
- Paint
- Dirt
- Rust
- Any fluids or moisture
Personal injury can result from flame cutting or welding on painted areas. The effect of gasses from burned paint is a hazard to the person doing the cutting or welding. Do not flame cut or weld on painted areas. |
Preheating & Interpass Temperature
Note: Be sure that the temperature of the base metal is at least
Note: Heat distortion of the base metal is possible when you weld. Avoid excessive heating of the base metal.
Pre heat repair area approximately
The preheat and interpass temperature shall be checked with a temperature indicating crayon prior to initiating the arc each pass.
Illustration 84 | g06035333 |
(F) Infrared Thermometer
(G) Temperature Indicating Crayon |
Welding Techniques
Illustration 85 | g06111648 |
Weld layer technique after crack excavation. (A) Weld Beads (B) Weld Layers |
Welding technique (example: the manipulation of the welding electrode and deposition pattern of the weld metal), is important in producing a quality salvage weld. Weld beads can be placed as in Illustration 85 for crack repair.
- Weld metal shall be deposited in weld beads and layers as shown in Illustration 85.
- Puddling or continuing to weld with the electrode nearly stationary or in a tight circular pattern shall not be done.
- The width of weld beads deposited in the vertical position of welding shall not exceed 1-1/2 times the width shown for the flat position. Do not weld in a vertical down progression.
- The rate of travel and width of weaving shall be controlled to maintain the prescribed limits on the width of weld beads.
- Tables 23 are suggested electrodes and parameters to be used during weld repairs.
Post Weld Treatments
Post Weld Treatments include the slow cooling, and finishing.
Slow Cooling
Illustration 86 | g03824505 |
Typical example of a welding blanket. |
Immediately after welding is complete, cover the weld with a welding blanket for slow cooling to reduce the chance of hydrogen cracking. The use of an insulated welding blanket is recommended to retain the heat.
Welding Procedure for Cracks in the Rear Spindle of 770 through 797 OHT
Protect machined surfaces from sparks. Protect the machined surfaces from the welding spatter.
- Weld the spindle in a standard position (horizontal for 793 and below, vertical for 797).
- For each weld pass, the fillet width must not exceed
8 mm (0.3 inch) . Use stringer welds for each weld pass. - After each weld pass, needle peen the weld. Ensure that all the slag is removed.
- Grind the crest of the weld to the original profile of the casting.
- Visually inspect the weld and the surrounding area for defects.
- After completing the repair, heat the weld area to
149° C (300° F) and allow the casting to cool slowly to room temperature.
Special Weld Procedure for Zone F on 789, 793, and 797 Spindles
- For ease of welding and quicker repairs place the spindle in the horizontal position. The spindle in the horizontal position will aid in ergonomics.
Show/hide table
Illustration 87 g03681922 View of excavated crack with room to manipulate the weld arc. - Verify that the excavated area has been dressed so that there is enough room to weld.
If the area being repaired has not been dressed appropriately, the welder performing the weld repair should grind the repair area to ensure full access and torch manipulation. Refer to Illustration 87.
Note: The welder should make a final clean out pass with the deburring tool.
- Once the area to be welded is repaired and has been fully excavated and dressed, use a ruler or tape measure and chalk to mark the
100 mm (4.00 inch) zone surrounding the excavation.Show/hide tableIllustration 88 g03681925 Typical view of a rosebud torch. Show/hide tableIllustration 89 g03681935 View of preheating the repair area. - Use a rosebud torch to preheat the marked zone to a temperature of
200° C (400° F) to250° C (480° F) . Verify the surface temperatures at the margins of the marked zone using the appropriate temperature stick or infrared gun. This temperature must be maintained throughout the weld process.Show/hide tableIllustration 90 g03681943 Weld pass progression to fill the excavated crack. - Excavated cracks are to be repaired using a weld pass width no greater than
8 mm (0.30 inch) . If one pass does not fill the repair, continue to weld until the excavated area is full.Note: Change directions of travel for each pass to stagger the stop and start points.
Show/hide tableIllustration 91 g03681945 Example of an incorrect weld with passes in one direction only and start/stop points not staggered. - Completely remove the slag after each weld pass and check the surface temperature near the weld to ensure interpass temperature of
200° C (400° F) . If necessary, use the torch to reheat area to between200° C (400° F) and250° C (480° F) before the next pass. - When welding is complete, reheat the repaired area to a temperature between
200° C (400° F) to230° C (450° F) . Verify the surface temperature with the appropriate temperature stick or infrared gun.Show/hide tableIllustration 92 g03681946 View of welding blanket covering the weld repair area after post-weld heating. - Cover the weld repair area with welding blankets immediately after post weld heating. The covered area should extend at least
300 mm (12.00 inch) in each direction beyond the weld repairs. - Allow the spindle to cool to a temperature of
38° C (100° F) or lower before removing the welding blankets. - Repeat Step 7 and Step8 for all weld repaired areas.
- Grind the weld repair areas to approximate the original surface. Blend all welding transitions and grind areas with the original cast surface. Sharp edges or corners are not allowed.
- Inspect the weld repairs a final time using wet magnetic particle to ensure weld quality.
- Needle-peen the weld repair.
- Wire brush Zone (B), Zone (C), and Zone (F) and clean.
- Ensure that all weld spatter is removed from the spindle.
Show/hide table
Illustration 93 g03681950 (K) 40 mm (1.57 inch) Radius
(L) Brake Anchor Pilot Diameter - If a repair is made in Zone (C), behind the brake flange then the radius must be ground to the original dimension (K) shown in Illustration 93. A template can easily be cut from cardboard for a reference.
- Weld repairs which intersect the machined diameters on either side of the brake flange must be ground to approximate the original surface. Special care must be taken to avoid damaging the brake anchor pilot diameter (L) on Zone (B) side of the brake flange.
Run-Out Checks
NOTICE |
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Check radial run-out to ensure that applicable components are within specification. Failure to check radial run-out will result in premature bearing failure. |
Surface Texture Inspection & Testing
Weld repairs that do not get machined should be ground flush or shaped to match the profile of the surrounding material. Shaping can be done with a hand grinder and flexible sanding discs, however care must be taken not to contaminate the bearing components. The repair shall have no visible defects present such as rollover, undercut, porosity, or slag inclusions. Each repair should be inspected using NDT, refer to the "Crack Detection Methods" section.
Surface Texture Inspection
Illustration 94 | g06130307 |
Typical example of checking surface texture using comparison gauge (A). (A) Comparison Gauge |
Surface Texture Testing
Illustration 95 | g06408018 |
Profilometer |
Ensure that several samples are taken on machined journals using a surface texture tester to verify that the surface meets texture specifications. Refer to the specific component acceptable dimensions and tolerances table for surface texture specifications. For more information on surface texture.
Hardness Checks
Hardness should be measured using a suitable type hardness tester. Persons should be qualified or properly trained in how to use the hardness tester to ensure good results.
Preferred Option
Measure the hardness of bearing journals. The hardness must be at a minimum of 45 Rockwell C.
You may also use a C rated Rockwell tester. The tester must not leave marks. The GE MIC 10 measures in HRC and is the recommended tester for heat-treated materials, HVOF, and Arc Spray coatings.
The tolerance of the OD for each journal is
The alignment of each journal must be measured to a tolerance of
Alternative Option
Note: A minimum hardness reading of 45 Rockwell "C" (RC) or 430 Brinell (10 mm steel ball) is required.
Directions for using a Detroit Hardness Tester
Follow Steps 1 through 8 for using a Detroit Hardness Tester:
- Locate area to be tested.
- Use a non-metallic synthetic buffing wheel to clean bottom of grooves in area to be hardness tested.
- Turn tester upside down allowing the ball to seat in the cap.
Show/hide table
Illustration 96 g06225781 Typical example of testing the hardness of the chrome layer on a hydraulic cylinder rod.
(E) Hardness TesterShow/hide tableIllustration 97 g06398309 Typical Example
(E) Hardness Tester. - Turn tester right side up and place on area that has been cleaned. Refer to Step 2.
- Hold tester vertically and steady.
- Slowly depress trigger, do not strike or you will get an inaccurate reading.
- Read the top of the ball at the highest point of the ball's bounce.
- Repeat Steps 3 through 7 for each test location three times to obtain an accurate reading.
Thermal Spray Procedures for OHT Rear Spindles
Preparation of a spindle is critical to achieve the desired bond and the desired finish of the coating.
Part Description
Base Metal | Steel casting or forging |
Hardness | 28-34 rc |
Arc Spray Equipment and Procedure
Maximum Surface Texture | |
Reason for Spraying | Wear or grooving |
Mating Part Contact Area & Material | Inner bearing race |
Arc Spray Equipment Type | SmartArc by Oerlikon Metco,TAFA 8830 MHU, or TAFA 8835 MHU |
Wire | TAFA 90MXC Wire Top Coat, TAFA 75B Bond Coat |
Finish Thickness | As Required |
Spray Angle | 90° |
Substrate Pre-Heat Temperature | |
Substrate Temperature During Spraying Not to Exceed | |
Auxiliary Cooling | Filtered shop air |
Rotation/Traverse Device | Lathe or headstock/tailstock arrangement, rotary turntable |
Rotation Speed | |
Surface Preparation Method | Undercut and Grit blast if necessary |
Equipment Required | Turn Vertical Lathe |
Recommended Cutting Tool | ISCAR DNMG 432 TF IC507 |
Blast Media Recommendation | Pressure Type Only (Aluminum Oxide Grit) |
Arc Spray | Procedure | Check List | |
Clean Part | Degrease in hot caustic solution | ||
Undercut | To "tru-up" surface | ||
Chamfer | If required - |
||
Remove Oxide | Use fiber flap brush or Clean/strip disc | ||
Clean Spray Area | Commercial degreaser | ||
Mask for Grit Blaster | Duct Tape | ||
Grit Blast Equipment | Pressure type only | ||
Grit Type and Size | 20 mesh aluminum oxide | ||
Blast Air Pressure | |
||
Blast Nozzle to Work Distance | |
||
Remove Blast Mask | Make sure that surface is clean | ||
Mask for Metal Spray | Antibond or Blue Layout Dye | ||
Metal Spray Equipment Type | Smart Arc by Oerlikon Metco | TAFA | |
Consumable (Bondcoat) | TAFA 75B | TAFA 75B | |
Clamp Pressure | |
||
Air Jets/Pressure | |
|
|
Arc Load Volts | 30V | 30V | |
Amps | 125 Amps | 150 Amps | |
Gun to Work Distance (Standoff) | |
|
|
Spray Rate/Bond Pass | |
|
|
Consumable (Topcoat) | TAFA 90 MXC | TAFA 90 MXC | |
Clamp Pressure | |
||
Air Jets/Pressure | |
|
|
Arc Load Volts | 32V | 32V | |
Amps | 125 Amps | 150 Amps | |
Gun to Work Distance (Standoff) | |
|
|
Spray Rate/Build Up | |
|
|
Rotation Speed of Part (RPM) | RPM varies depending on diameter (52 to 143 RPM) | ||
Rotation Speed of Part | |
||
Traverse Rate of Gun | |
||
Gun Fixturing Method | Machine mount or hand held | ||
Finishing Equipment | Lathe | ||
Part/Cutter Rotation | Roughing Finishing |
||
Coolant | Oil base synthetic - 40:1 ratio | ||
Traverse Speed | |
||
Depth of Rough Cut | |
||
Depth of Finish Cut | |
HVOF Spray Equipment and Procedure
Maximum Surface Texture | |
Reason for Spraying | Wear |
Mating Part Contact Area & Material | Bearing |
Oerlikon Metco Equipment Type | Diamond Jet Hybrid Spray System |
Material | Metco 1008 |
Finish Thickness | As Required |
Finishing Allowance | |
Spray Angle | 90° |
Spraying Not to Exceed | |
Auxiliary Cooling | Filtered shop air |
Rotation/Traverse Device | Lathe or headstock/tailstock arrangement, rotary turntable |
Rotation/Traverse Speed | |
Surface Preparation Method | Machine to "tru-up" surfaces and Grit blast |
Machining Method | Turn or Grind |
Recommended Equipment | Turn (Lathe) / Grind (Finishers Tech) |
Recommended Cutting Tool | Kennametal DNMP, Grade K313 or equivalent |
Blast Media Recommendations | Pressure type Only (20 Mesh Aluminum Oxide Grit)
Blast Profile: |
Finishing and Superfinishing Equipment Type | Diamond Belt Grinding |
Grinding Equipment | Finishers Tech Super G-6 Belt Grinder or equivalent |
Recommended Abrasive | 3MTM TrizactTM Diamond Cloth Belts 663FC (70 micron) |
Superfinishing Equipment | Supfina 210, IMPCO, GEM, or equivalent |
Recommended Abrasive | 3MTM Diamond Microfinishing Film (20 micron) |
Remarks | If at anytime during spraying oil evolves from the casting, metal spraying must stop. Remove the coating and start the preparation procedure over from the beginning. If this is not done, the coating will fail during machining or during service. |
HVOF Spray Process (Hybrid Gun) | Salvage Procedure | Check List |
Straighten Part | Step 1 | |
Equipment Necessary | ||
Maximum Runout Allowed | ||
"Tru-up" Coating Surface | Step 2 | |
Rotational and Positioner Equipment | ||
Coolant | ||
Grinding Requirements | ||
Grinding Equipment | Finishers Tech Super G-6 grinding machine or equivalent | |
Contact Wheel | |
|
Contact Wheel vs. Rod Rotational Direction | Opposing Directions (Rotate towards the contact area) | |
Abrasive | 3MTM CubitronTM Cloth Belts 966F 24 grit | |
Idler Force | 70 - 100 lbs idler force per inch of belt width | |
Belt Speed | |
|
Part Rotational Speed | |
|
Rotation Speed Of Part (RPM) | RPM varies depending on diameter | |
Traverse Speed | |
|
Turning Requirements | ||
Recommended Cutter Grade | Kennametal DNMP, Grade K313 or equivalent | |
Part/Cutter Rotation (SFPM) | |
|
Traverse Speed | |
|
Depth Of Cut | |
|
Rotation Speed Of Part (RPM) | RPM varies depending on diameter | |
Clean the Spray Area | Step 3
A) Degrease in hot caustic solution or wipe with a degreasing agent B) Vapor degrease or set on a turntable and use a torch to heat to C) Drench bearing areas in Zep I.D. Red or equivalent |
|
Surface Preparation (Grit Blaster) | Step 4 | |
Mask For Blast | A) Mask off areas, leave B) Add a graphite plug-in keyways and round edges to prevent shadowing during metal spray operation C) The bearing surfaces must be grit blasted to a roughness of 7.5 micrometer (300.00 microinch) |
|
Blast Equipment | Pressure Type Only | |
Grit Type And Size | 20 mesh Aluminum Oxide | |
Blast Profile | |
|
Blast Air Pressure | |
|
Blast Nozzle to Work Piece Distance | |
|
Remove Blast Masking | Remove blast-masking material and make sure that the surfaces are clean, but leave graphite plug in place | |
HVOF Coating | Step 5 | |
HVOF Application of Coating | A) Install spindle into lathe or headstock/tailstock arrangement. Set up shadow masks in front of spline area and at turnaround point. The shadow masks block heat transfer prevent overheating. Grit blast the shadow mask so that coating will adhere to the mask. Turn the shadow masks at a slight angle (20°) to prevent overspray from hitting the sprayed bearing surface.
B) Perform a final degrease with trichloroethylene or Zep I.D. Red. Rotate the spindle during the degreasing operation. C) Monitor coating surface temperature with an optical pyrometer. Do not allow the spindle to reach D) Every 10 passes stop spraying to allow cool down and check lathe chuck for tightness. E) Overspray the diameter to allow for cleanup and shrinkage upon cooling. |
|
Refer to SEBF9236 for HVOF spray parameters. | ||
HVOF Grinding Or Turning | Step 6 | |
Rotational and Positioner Equipment | Lathe or headstock/tailstock arrangement | |
Coolant | Use flood coolant of water with 5% Synthetic coolant such as Milicron 46C or equivalent. | |
Turning Requirements | ||
Recommended Cutter Grade | Kennametal DNMP, Grade K313 or equivalent | |
Part/Cutter Rotation - Rough Cut | |
|
Traverse Speed - Rough Cut | |
|
Depth Of Cut - Rough Cut | |
|
Rotation Speed Of Part (RPM) - Rough Cut | RPM varies depending on diameter | |
Final Pass Depth Of Cut For Finishing | |
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Turning Instructions | ||
1) Leave the graphite plug in the keyway. Hand file the graphite plug flush with the coating.
2) Start cutting 3) Once a 4) The machining can be performed dry, but a thin film of oil will increase insert life and provide a better surface finish. |
||
HVOF Grinding Requirements | ||
Grinding Equipment | Finishers Tech Super G-6 Grinding Machine | |
Contact Wheel | Plain face, Incompressible (Aluminum, steel or other), |
|
Abrasive | 3MTM TrizactTM Diamond Cloth Belts 663FC (70 micron) | |
Contact Wheel Vs. Rod Rotational Direction | Opposing Directions (Rotate towards the contact area) | |
Belt Speed | |
|
Idler Force | 70 - 100 lbs idler force per inch of belt width | |
Part Rotational Speed | |
|
Rotation Speed Of Part (RPM) | RPM varies depending on diameter | |
Traverse Speed | |
|
Infeed Per Pass (inches on diameter) | |
|
HVOF Superfinishing Requirements | ||
Superfinishing Equipment | Supfina 210, IMPCO, GEM, or equivalent | |
Contact Wheel | Plain face, 60 Shore A hardness | |
Abrasive - HVOF Superfinishing | 3MTM Diamond Microfinishing Film 675L (20 micron) | |
Contact Force | 20-40 lbs | |
Abrasive Feed Rate | |
|
Belt Oscillation (Machine Setting) | Optional | |
Spindle Speed | |
|
Rotation Speed Of Part (RPM) | RPM varies depending on diameter | |
Traverse Speed | |
Note: Contact wheels are to be
70 micron -
40 micron -
20 micron -
Belt Roll Grinding
Recommended Operating Parameters |
|||||
Abrasive | 3MTM TrizactTM Diamond Cloth Belts 663FC | ||||
Contact Wheel | Smooth Faced / Incompressible (Aluminum, 65 Shore D, Steel) | ||||
Belt Width | 2 inches* | ||||
Belt Speed | 6,000 SFPM | ||||
End of Roll Dwell | 1/2 Overlap - 2 Revolutions | ||||
Shoulder Grind - 5 revolutions | |||||
* Wider belt allows faster traverse | |||||
** Higher infeed traverse combinations have been achieved using cylindrical roll grinders | |||||
=75 SFPM | =0.25 inch/rev. | Chrome Carbide (CAT) | |||
Grinding Infeeds | |||||
Rod Diameter | RPM | Traverse Rate | Infeed Per Pass (on diameter) | ||
---|---|---|---|---|---|
(inches) | (Workpiece) | (inch/min) | 663FC 70-micron | 663FC 40-micron | 663FC 20-micron |
Ø 1.50 | 191.0 | 47.7 | 0.0025 | 0.0017 | 0.0008 |
Ø 2.00 | 143.2 | 35.8 | 0.0025 | 0.0017 | 0.0008 |
Ø 2.50 | 114.6 | 28.6 | 0.0025 | 0.0017 | 0.0008 |
Ø 3.00 | 95.5 | 23.9 | 0.0025 | 0.0017 | 0.0008 |
Ø 3.50 | 81.9 | 20.5 | 0.0025 | 0.0017 | 0.0008 |
Ø 4.00 | 71.6 | 17.9 | 0.0025 | 0.0017 | 0.0008 |
Ø 4.50 | 63.7 | 15.9 | 0.0025 | 0.0017 | 0.0008 |
Ø 5.00 | 57.3 | 14.3 | 0.0025 | 0.0017 | 0.0008 |
Ø 5.50 | 52.1 | 13.0 | 0.0025 | 0.0017 | 0.0008 |
Ø 6.00 | 47.7 | 11.9 | 0.0025 | 0.0017 | 0.0008 |
Ø 6.50 | 44.1 | 11.0 | 0.0025 | 0.0017 | 0.0008 |
Ø 7.00 | 40.9 | 10.2 | 0.0025 | 0.0017 | 0.0008 |
Ø 7.50 | 38.2 | 9.5 | 0.0025 | 0.0017 | 0.0008 |
Ø 8.00 | 35.8 | 9.0 | 0.0025 | 0.0017 | 0.0008 |
Ø 8.50 | 33.7 | 8.4 | 0.0025 | 0.0017 | 0.0008 |
Ø 9.00 | 31.8 | 8.0 | 0.0025 | 0.0017 | 0.0008 |
Ø 9.50 | 30.2 | 7.5 | 0.0025 | 0.0017 | 0.0008 |
Ø 10.00 | 28.6 | 7.2 | 0.0025 | 0.0017 | 0.0008 |
Ø 10.50 | 27.3 | 6.8 | 0.0025 | 0.0017 | 0.0008 |
Ø 11.00 | 26.0 | 6.5 | 0.0025 | 0.0017 | 0.0008 |
Ø 11.50 | 24.9 | 6.2 | 0.0025 | 0.0017 | 0.0008 |
Ø 12.00 | 23.9 | 6.0 | 0.0025 | 0.0017 | 0.0008 |
Ø 12.50 | 22.9 | 5.7 | 0.0025 | 0.0017 | 0.0008 |
Ø 13.00 | 22.0 | 5.5 | 0.0025 | 0.0017 | 0.0008 |
Ø 13.50 | 21.2 | 5.3 | 0.0025 | 0.0017 | 0.0008 |
Ø 14.00 | 20.5 | 5.1 | 0.0025 | 0.0017 | 0.0008 |
Ø 14.50 | 19.8 | 4.9 | 0.0025 | 0.0017 | 0.0008 |
Ø 15.00 | 19.1 | 4.8 | 0.0025 | 0.0017 | 0.0008 |
Superfinishing Chrome Carbide
Recommended Operating Parameters |
|||||
Abrasive | 3MTM Diamond Microfinishing Film 675L (20 micron) | ||||
Film Feed Rate | 0.33 inch/min | ||||
Applied Force | 25 lb/inch | ||||
Oscillation | Low (Low/None: final pass) | ||||
Film Width | 2 inch* | ||||
# of Passes | 1 - 2 passes with a 25 - 35 Ra input finish** | ||||
Obtainable Surface Texture | |
||||
* Wider film allows faster traverse | |||||
** Finish obtained with 3MTM 663FC 70 micron | |||||
=300 SFPM | =0.0625 inch/rev. | ||||
Rod Diameter | RPM | Traverse Rate | |||
---|---|---|---|---|---|
(inches) | (Workpiece) | (inch/min) | |||
Ø 1.50 | Ø764.0 | 47.7 | |||
Ø 2.00 | 573.0 | 35.8 | |||
Ø 2.50 | 458.4 | 28.6 | |||
Ø 3.00 | 382.0 | 23.9 | |||
Ø 3.50 | 327.4 | 20.5 | |||
Ø 4.00 | 286.5 | 17.9 | |||
Ø 4.50 | 254.7 | 15.9 | |||
Ø 5.00 | 229.2 | 14.3 | |||
Ø 5.50 | 208.4 | 13.0 | |||
Ø 6.00 | 191.0 | 11.9 | |||
Ø 6.50 | 176.3 | 11.0 | |||
Ø 7.00 | 163.7 | 10.2 | |||
Ø 7.50 | 152.8 | 9.5 | |||
Ø 8.00 | 143.2 | 9.0 | |||
Ø 8.50 | 134.8 | 8.4 | |||
Ø 9.00 | 127.3 | 8.0 | |||
Ø 9.50 | 120.6 | 7.5 | |||
Ø 10.00 | 114.6 | 7.2 | |||
Ø 10.50 | 109.1 | 6.8 | |||
Ø 11.00 | 104.2 | 6.5 | |||
Ø 11.50 | 99.6 | 6.2 | |||
Ø 12.00 | 95.5 | 6.0 | |||
Ø 12.50 | 91.7 | 5.7 | |||
Ø 13.00 | 88.1 | 5.5 | |||
Ø 13.50 | 84.9 | 5.3 | |||
Ø 14.00 | 81.9 | 5.1 | |||
Ø 14.50 | 79.0 | 4.9 | |||
Ø 15.00 | 76.4 | 4.8 |
Crack Detection Methods
NOTICE |
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Regardless of which crack detection method is used, it is important that the instructions furnished with the detection equipment are followed closely when checking any component. Failure to do so may cause inaccurate results or may cause injury to the operator and/or surroundings. |
Crack detection methods or Non-Destructive Testing (NDT) is methods for testing spindles components for cracks without damaging the component. VT, PT, and Dry/ Wet MT, are methods recommended. There may be more than one acceptable crack detection method for the testing of a given part, although PT is the most versatile. For example, the PT method can be used when testing smooth machined components such as shafts, gear teeth, and splines, but using the Wet MT is more accurate. Refer to Table 31 for advantages and disadvantages and Table 32 for standards and requirements for these NDT methods.
Crack Detection Methods Advantages vs. Disadvantages | ||
---|---|---|
Detection Method | Advantages | Disadvantages |
Visual Surface Inspection (VT) | - Least Expensive
- Detects most damaging defects. - Immediate Results - Minimum part preparation |
- Limited to surface-only defects.
- Requires inspectors to have broad knowledge of welding and fabrication in addition to Non-Destructive Testing (NDT). |
Liquid Penetrant Testing (PT) | - Inexpensive
- Minimal Training - Portable - Works on nonmagnetic material. |
- Least Sensitive
- Detects surface cracks only. - Rough or porous surfaces interfere with test |
Dry Magnetic Particle (MT) | - Portable
- Fast/Immediate Results - Detects surface and subsurface discontinuities |
- Works on magnetic material only.
- Less sensitive than Wet Magnetic Particle Testing (MT). |
Wet Magnetic Particle (MT) | - More sensitive than Liquid Penetrant Testing (PT).
- Detects subsurface as much as |
- Requires power for light.
- Works on magnetic material only. - Liquid composition and agitation must be monitored. |
Applicable Crack Detection Standards | |||
---|---|---|---|
Detection Method | Standard | Acceptance
Criteria |
Minimum
Required Personnel Qualifications |
Visual Surface Inspection (VT) | EN-ISO 5817
AWS D1.1 |
EN-ISO 5817 - Level B
AWS D1.1 - Table 6.1 |
EN-ISO 9712
ANSI-ASNT SNT-TC-1A |
Liquid Penetrant Testing (PT) | EN-ISO 3452
ASTM E165 |
EN-ISO 23277
AWS - D1.1 |
EN-ISO 9712
ANSI-ASNT SNT-TC-1A |
Magnetic Particle Testing (MT) | EN-ISO 17638
ASTM E709 |
EN-ISO 23278 - Level 1
AWS D1.1 - Table 6.1 |
EN-ISO 9712
ANSI-ASNT SNT-TC-1A |
Visual Surface Inspection (VT)
Illustration 98 | g06085008 |
Example of Visual Surface Inspection (VT) Tooling (A) Flashlight (or adequate light source) (B) Magnifying Glass (C) Tape Measure (or other measuring device) (D) Inspection Mirror (E) Weld Size Inspection Gauges |
Refer to Tooling and Equipment Table 3 for part numbers.
Components and welds that are to be tested using PT, MT, or UT shall first be subject to a Visual Surface Inspection (VT). VT is often the most cost-effective inspection method and requires little equipment as seen in Illustration 98. Personnel performing VT shall either be trained to a company standard or have sufficient experience and knowledge regarding the components being inspected. Personnel performing VT shall take routine eye exams.
Liquid Penetrant Testing (PT)
Personal injury can result from improper handling of chemicals. Make sure you use all the necessary protective equipment required to do the job. Make sure that you read and understand all directions and hazards described on the labels and material safety data sheet of any chemical that is used. Observe all safety precautions recommended by the chemical manufacturer for handling, storage, and disposal of chemicals. |
Materials and Equipment Required
Refer to Tooling and Equipment Table 3 for part numbers.
- Cleaner: Removes dirt before dye application and dissolves the penetrant making possible to wipe the surface clean.
- Penetration Oil: This solution is highly visible, and will seep into openings at the surface of a part with capillary action.
- Developer: Provides a blotting action, bringing the penetrant out of the discontinuities and providing a contrasting background to increase the visibility of the penetrating oil indications.
- Wire Brush: Removes dirt and paint.
- Cloth or Wipes: Use with cleaner and for other miscellaneous uses.
Procedure
- Preclean the area to be tested. Spray on cleaner/ remover to loosen any scale, dirt, or any oil. Wipe the area to be tested with a solvent dampened cloth to remove remaining dirt and allow the area to dry. Remove paint where there are visible cracks using paint remover or a wire brush.
Show/hide table
Illustration 100 g06084053 Typical example of applying penetrating oil to areas to be tested. - Apply penetrating oil by spraying to the entire area to be tested. Allow 10 to 15 minutes for penetrating oil to soak. After the penetrating oil has been allowed to soak, remove the excess penetrating oil with clean, dry wipe.
Show/hide table
Illustration 101 g06084060 Typical example of removing penetrating oil with a cloth. - The last traces of penetrating oil should be removed with the cleaner solvent dampened cloth or wipe. Allow the area to dry thoroughly.
Show/hide table
Illustration 102 g06084070 Typical example of applying the developer. - Before using developer, ensure that the developer is mixed thoroughly by shaking the container. Hold the container approximately
203 - 305 mm (8 - 12 inch) away from part. Apply an even, thin layer of developer over the area being tested. A few thin layers are a better application method than one thick layer.Show/hide tableIllustration 103 g03773759 Typical example of cracks found during Liquid Penetrant Testing (PT). - Allow the developer to dry completely for 10 to 15 minutes before inspecting for cracks. Defects will show as red lines in white developer background, refer to Illustration 103. Clean the area of application of the developer with solvent cleaner.
Illustration 99 | g06084048 |
Typical example of pre-cleaning the testing area. |
Dry Magnetic Particle Testing (MT)
Materials and Equipment Required
Refer to Tooling and Equipment Table 3 for part numbers.
Illustration 104 | g06085930 |
(A) Indications shown by Dry Magnetic Particle Testing (MT).
(B) Electromagnetic Yoke (C) Dry Powder Bulb |
- Dry magnetic powder shall be of high permeability and low retentively and of suitable sizes and shapes to produce magnetic particle indications. The powder shall be of a color that will provide adequate contrast with the background of the surface being inspected.
- Dry magnetic particles shall be stored in suitable containers to resist contamination such as moisture, grease, oil, non-magnetic particles such as sand, and excessive heat. Contaminants will manifest in the form of particle color change and particle agglomeration. The degree of contamination will determine further use of the powder.
- Dry magnetic powder shall be tested in accordance with ASTM E709 Section 18 (Evaluation of System Performance/Sensitivity) when not performing.
- Equipment should include a "U" shaped electromagnetic yoke made from highly permeable magnetic material, which has a coil wound around the yoke. This coil carries a magnetizing current to impose a localized longitudinal magnetic field into the part. The magnetizing force of the yoke is related to the electromagnetic strength and can be tested by determining the lifting power of a steel plate. The yoke shall have a lifting force of at least
4.5 kg (10 lbs) . - Check dry powder blower routinely to ensure that the spray is a light, uniform, dust-like coating of the dry magnetic particles. Blower should also have sufficient force to remove excess particles without disturbing those particles that are evidence of indications.
- All equipment shall be inspected at a minimum of once a year or when accuracy is questionable.
Procedure
- Ensure surface to be inspected is dry and free from oil, grease, sand, loose rust, mil scale, paint, and other contaminants.
- Apply the magnetic field using the yoke against the faces and inside diameter of each bore.
- Simultaneously apply the dry powder using the dry powder blower.
- Remove excess powder by lightly blowing away the dry particles.
- Continue around the entire circumference of each bore. Position the yoke twice in each area at 1.57 rad (90°) to ensure that multiple directions of the magnetic field are created.
- Observe particles and note if any clusters of particles appear revealing an indication.
- Record the size and shape of any discontinuities or indications found.
Wet Magnetic Particle Testing (MT)
Materials and Equipment
Refer to Tooling and Equipment Table 3 for part numbers.
Illustration 105 | g03680525 |
Spectronics BIB-100P Black Light |
Illustration 106 | g03680529 |
Magnaflux ZB-100P Black Light |
An approved black light must be used to perform this procedure. Currently the Spectronics BIB-100P or the Magnaflux ZB-100P lights are used. Black lights should be certified annually. The minimum acceptable intensity shall be 1000µW/cm2 at
Illustration 107 | g06399664 |
Contour Probe DA-200 Magnetic Yoke |
An approved magnetic yoke must be used to magnetize the damaged areas. Currently the Contour Probe DA-200 Electric Yoke is used. The magnetic yokes should be certified annually. Dead weight check requirements for AC yokes should be capable of lifting
Illustration 108 | g06399667 |
Parker Research TB-10 Weight Lift Test Bars |
Dead weight bars or lift bars are used to measure the lifting capability of the magnetic yoke at maximum leg spacing. Currently the preferred bars are Parker Research TB-10 Weight Lift Test Bars. Yokes should be placed on the bars at maximum leg spacing for both AC and DC. AC yoke capability is
Illustration 109 | g06399669 |
Magnaflux Magnaglo Fluorescent Particles |
A magnetic particle solution is used to illuminate the cracked or damaged area. Currently Magnaglo 20B is preferred. Particle mix should only be used if the concentration is within the range of
Illustration 110 | g03680543 |
Typical Sprayer used to apply fluorescent particle mixture. |
Wet magnetic particles are fluorescent and are suspended in a cold water to a given concentration that will allow application to the test surface by spraying. Particle solution should be agitated by shaking the sprayer at regular intervals during testing.
Illustration 111 | g06003178 |
Typical 100 ml Centrifuge Tube |
- Concentration:
- The concentration of the suspended magnetic particles shall be as specified by the manufacturer and be checked by settling volume measurements.
- Concentrations are determined by measuring the settling volume by using an ASTM pear shaped centrifuge tube with a
1 mL (0.034 oz) stem with0.05 mL (0.0017 oz) divisions, refer to Illustration 111. Before sampling, the suspension shall be thoroughly mixed to assure suspension of all particles, which could have settled. A100 mL (3.40 oz) sample of the suspension shall be taken and allowed to settle for 30 minutes. The settling volume should be between0.1 mL (0.0034 oz) and0.25 mL (0.0085 oz) in a100 mL (3.40 oz) sample. - Wet magnetic particles may be suspended in a low viscosity oil or conditioned water.
- The oil shall have the following characteristics:
- Low viscosity not to exceed
5 mm2/s (5 cSt) at any temperature at which the vehicle is to be used. - Low inherent fluorescence and be non-reactive.
- Low viscosity not to exceed
- The conditioning agents used in the conditioned water shall have the following characteristics:
- Impart good wetting characteristics and good dispersion.
- Minimize foaming and be non-corrosive.
- Low viscosity shall not exceed a maximum viscosity of
5 mm2/s (5 cSt) at38° C (100° F) . - Non-fluorescent, non-reactive, and odorless.
- Alkalinity shall not exceed a pH of 10.5.
Illustration 112 | g06399672 |
Magnaflux Spotcheck SKC-S Cleaner |
All areas to be Magnetic Particle tested must be cleaned before inspection. Currently Magnaflux Spotcheck SKC-S is used to clean the areas to be inspected. Gloves should be worn during use.
Illustration 113 | g06399675 |
Typical Inspection Canopy |
The inspection canopy is used to create a darkened environment suitable for Fluorescent Magnetic Particle testing. The inspection canopy should be large enough to accommodate large components.
Illustration 114 | g06399676 |
Gould-Bass DLM-1000 Radiometer |
A Black and White Light Meter is used to measure light intensity. Currently the Gould-Bass DLM-1000 Radiometer is used and should be certified annually. The maximum ambient visible light at the inspection surface is 2fc (20lx). This is light observed under the inspection canopy during magnetic particle examinations. This measurement should be checked and recorded on a monthly basis. The minimum acceptable black light intensity should be 1000µW/cm2 at
Procedure
- Ensure surface to be inspected is dry and free from oil, grease, sand, loose rust, mil scale, paint, and any other contaminants.
- Apply the magnetic field using the yoke against the surface in the area to be inspected.
Show/hide table
Illustration 115 g03536210 - For case hardened and ground surfaces:
- Due to the sensitivity required to locate the grinding cracks, inspection of case hardened and ground surfaces require that the yoke is applied so that the magnetic field is 1.57 rad (90°) to the expected direction of the indications. Also, due to the increased sensitivity resulting when the yoke is energized, the yoke is not moved until the evaluation is completed in the first direction. An AC yoke shall be used. See Illustration 115 for an example of yoke placement.
- Visually inspect for indications of discontinuities using the proper illumination.
- Record the size and shape of any discontinuities found.