PRODUCT SUPPORT PROGRAM FOR INSPECTING THE TOP FRONT CASE TO FRAME BUTT WELDS ON CERTAIN D11T TRACK-TYPE TRACTORS THAT ARE IN THEIR SECOND LIFE Caterpillar

PRODUCT SUPPORT PROGRAM FOR INSPECTING THE TOP FRONT CASE TO FRAME BUTT WELDS ON CERTAIN D11T TRACK-TYPE TRACTORS THAT ARE IN THEIR SECOND LIFE

Usage:

TEBE4612-00

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25Apr2016

N030
N061
N08K
N187

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Containment - Before/After (Limited distribution)	PRODUCT SUPPORT PROGRAM FOR INSPECTING THE TOP FRONT CASE TO FRAME BUTT WELDS ON CERTAIN D11T TRACK-TYPE TRACTORS THAT ARE IN THEIR SECOND LIFE
7051		PS90582

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NOTE:

Caterpillar’s obligations under this Service Letter are subject to, and shall not apply in contravention of, the laws, rules, regulations, directives, ordinances, orders, or statutes of the United States, or of any other applicable jurisdiction, without recourse or liability with respect to Caterpillar.

NOTE:

This Containment Program can be administered either before or after a failure occurs. In either case the decision whether to apply the Program is made by the dealer and service rep. Obtain the service reps Goodwill Approver Code before completing the repair. EAME dealers should use their standard Industry Group specific goodwill approval codes. The Goodwill Approver Code must be included when submitting the claim.

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NOTE:	When reporting the repair, use "PS90582" as the Part Number and "7777" as the Group Number. If administered before failure, use "56" as Warranty Claim Description and "T" as the SIMS Description Code. If administered after failure, use "96" as Warranty Claim Description Code and use "Z" as the SIMS Description Code.
NOTE:	The information supplied in this service letter may not be valid after the termination date of this program. Do not perform the work outlined in this Service Letter after the termination date without first contacting your Caterpillar product analyst.

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TERMINATION DATE

30Apr2018

PROBLEM

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The top front butt welds can crack on certain D11T Track-Type Tractors in higher load applications during their 2nd life. If the butt welds crack, this can cause the inner and outer side sheets to crack, and eventually lead to a more extensive frame failure.

AFFECTED PRODUCT

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Model	Identification Number
D11T	GEB00729 JEL00200-00202, 211, 215, 217, 222, 225, 257, 262, 274, 309-310

PARTS NEEDED

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No parts needed for this program

ACTION REQUIRED

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Inspect per attached rework procedure.

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SERVICE CLAIM ALLOWANCES

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Product smu/age whichever comes first	Caterpillar		Dealer Suggested		Customer Suggested
Product smu/age whichever comes first	Parts %	Labor Hrs%	Parts %	Labor Hrs%	Parts %	Labor Hrs%
0-27000 hrs, 0-99 mo	100.0%	100.0%	0.0%	0.0%	0.0%	0.0%

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NOTE: This is a 3.5-hour job
Note 1: The 3.5 hours is for technication to remove and reinstall parts near inspection areas. Note 2: Up to $1100 (USD) per machine may be claimed for third party UT inspection. Note 3: Inspection results will need to be shared with Caterpillar.

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PARTS DISPOSITION

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Handle the parts in accordance with your Warranty Bulletin on warranty parts handling.

Rework Procedure

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SCOPE

This supplement will be used to inspect fully built units in the field. The intent is to inspect all welds that are easily accessible at the specific time and location of testing.

During inspection of in-service units only Visual and Ultrasonic Testing are required for the Top Left and Top Right Butt welds (Illustration 1 & 11 A & B) Visual only on the inboard top corner of the left and right side plate to front casting (Illustration 1 & 11 E & F). Magnetic particle testing can be used to supplement the visual testing if needed.

APPROVED INSPECTION METHODS

Visual inspection (VT), magnetic particle inspection (MT) and ultrasonic inspection (UT) are required for this inspection procedure. These inspection methods shall be conducted and reported by qualified personnel. Examples of qualified personnel are as follows: VT - AWS CWI (American Welding Society Certified Welding Inspector) or equivalent. MT/UT - ASNT (American Society of Nondestructive Testing) Level II (minimum) for each method used.

Note: Do not use the magnetic particle inspection process around components that will be affected by magnetism.

REQUIREMENTS FOR VISUAL (VT) TESTING

**Apparatus**
Bore Scope (VT): A bore scope can be utilized to inspect areas of the frame that are hidden behind hydraulic hoses or other attachments.

**Sample / Surface Preparation**
The surface shall be clean and free from oil, paint, scale, or any other foreign material that could interfere with visual inspection.

**Accept/Reject Criteria**
Cracks: Not Permitted

**D11 VT Inspection Areas**
Inspect Welds in Location A, B, E, and F per Illustration 1 / Image 1.10.1. VT inspect all surfaces of weld location A, B, E, and F that are visible and open to the outside surface or accessible with a bore scope.

REQUIREMENTS FOR MAGNETIC PARTICLE (MT) TESTING

**Personnel**
Personnel performing the inspections shall be at least Level II Certified Technicians in the Magnetic Particle Testing method, as defined by ASNT SNT-TC-1A, ASNT CP-189, or equivalent international standard.

Personnel performing the inspections shall be trained by a Level II or Level III, until the personnel show proficiency and understanding of procedures and rejection criteria.

**Apparatus**

**Magnetic Particle (MT) Yoke**
The MT Yoke shall be an AC (alternating current) type, capable of lifting a dead weight bar of 10 lbs. (4.5 kg) with a yoke leg spacing of 100-150mm (4-6 inch).

**Magnetic Particles**
Dry Visible type magnetic particles are recommended for use. Other types of particles or particle systems can also be utilized. White contrast paint is acceptable for use if applied in the proper manner and removed before welding.

**Sample / Surface Preparation**
The surface shall be clean and free from oil, paint, scale, or any other foreign material that could interfere with the magnetic particle inspection. Flame cut or carbon arc gouged surfaces shall be ground or sanded for proper inspection.

**Test Procedure**
Yoke Leg Placement: Yoke legs shall be placed in intimate contact with the part. The yoke leg spacing of 100-150mm (4-6 inch) shall be utilized. The yoke should be positioned in two positions in the area of interest the second being 90? perpendicular to the first, where possible.

**Continuous Magnetization Technique**
The yoke shall be energized before, during, and after the particles are applied. If dry particles are utilized the yoke shall stay energized during excess particle removal. If wet particles are utilized the yoke shall stay energized until after particles stop flowing. The yoke legs shall be placed in intimate contact with the part. The yoke leg spacing of 100-150mm (4-6 inches) shall be utilized.

**Accept/Reject Criteria**
Cracks ? Not Permitted
Lack of Fusion ? Not Permitted

**D11 MT Inspection Areas**
During In-Service Field Inspection: MT inspection should be used where possible but is not required. Inspect Welds in Location A, B, E, and F per Illustration 1. All paint shall be removed in the area of interest and can be a localized area if needed.

Image1.10.1

**MT Crack Removal and Repair**
Inspect areas after excavation and grinding to ensure complete removal of cracking or Lack of Fusion before re-welding.

After rewelding and grinding welds flush the weld area and heat affect zone shall be MT inspected for acceptance.

REQUIREMENTS FOR ULTRASONIC (UT) TESTING

**Personnel**
Personnel performing the inspections shall be at least Level II Certified Technicians in the Ultrasonic Testing method, as defined by ASNT SNT-TC-1A, ASNT CP-189, or equivalent international standard.

Personnel performing the inspections shall be trained by a Level II or Level III, until the personnel show proficiency and understanding of procedures and rejection criteria.

**Apparatus**

**Ultrasonic (UT) Instrument
The UT flaw detection instrument shall be capable of generating, receiving, and amplifying high-frequency electrical pulses at such frequencies and energy levels required to perform a meaningful examination and provide suitable readouts.

Preferred functions/features include but not limited to: inspection program recording, dual transducer capability, signal gating system, measurement data display, DAC/TCG recording, and 0 Db Reference.

UT instrument certification/qualification should be performed annually according to ASTM E317 or equivalent. This includes the verification of key performance characteristics, such as horizontal limit and linearity, vertical limit and linearity, resolution - entry surface and far surface, sensitivity and noise, accuracy of calibrated gain controls.

**Angle Beam / Shear Wave Search Unit
The ultrasonic transducer (probe, or search unit) shall be capable of transmitting and receiving ultrasound at the required frequencies and energy levels necessary for discontinuity detection in the material being examined. Frequencies of 2 MHz to 5 MHz shall be employed for angle-beam shear wave inspection.

Transducer crystal can be round, square, or rectangular. Crystal size recommended for weld examination shall be in the range of 9 mm (0.35 inch) to 25 mm (1.0 inch).

Selection of a transducer is determined by testing variables. Testing variables include weld thickness, testing surface, acceptable flaw size, flaw orientation, and the acoustic properties of the metal.

In angle-beam inspection, the wedge/shoe is attached to the transducer to generate the desired incident beam angle and wave mode in the parts. The common beam angles used in weld inspection are 45?, 60?, and 70?. The refracted angle shall be no greater than +/- 2? from normal. The edge distance shall not exceed 25 mm (1.0 inch). The wedge angles shall be selected according to information found in the "Probe Selection" section.

**Couplant**

Couplant is required between the face of the search unit and the examination surface. Couplant permits the transmission of ultrasonic waves from the search unit into the material under examination.

Typical couplants include cellulose gel, glycerin, and light machine oil. Corrosion inhibitors or wetting agents may be added. Couplants shall be selected that are not detrimental to the product or the process. Special couplant and search unit may be required at elevated temperatures (above 52? C or 125? F).

**Distance Calibration Blocks**
Refer to ASTM E164 for two options of distance calibration blocks. Other suitable blocks may be used.

Image1.16.1

Image1.16.2

**Sensitivity Calibration Blocks**
Three options for 1.5mm (0.06 inch) sensitivity calibration blocks are given but other blocks may be used. Option 1 Cat DAC Block is the preferred block type. Minimum requirements shall meet the requirement determined in the "Sensitivity Calibration" section.

One option for the 1mm (0.4 inch) flat bottom notch is given and will be provided.

For other sensitivity blocks: 1.5 mm (0.06 inch) side-drilled- holes (SDH) parallel to the inspection surface and perpendicular to the sound path shall be used as the calibration target.

Image1.17.1

Option 1: Cat? DAC Block 1.5 mm (0.06 inch) SDH's at 10 mm (0.40 inch) steps from the surface to include all depths over all thickness ranges to be used.

Use the dimensions in Illustration 4 / Image 1.17.1 to fabricate Cat? DAC Block using ASTM A572 Grade 42/50 steel.

Image1.18.1

Option 2: Cat? t Blocks: Blocks the same material and thickness as the parts to be tested. Machined 1.5 mm (0.06 inch) SDH's at 1/4t and 1/2t depths. Blocks must be long enough for full skip path and wide enough for the entire search unit to sit on the scanning surface.

Use the dimensions in Illustration 5 / Image 1.18.1 in order to fabricate Cat? t Blocks using ASTM A572 Grade 42/50 steel.

Image1.19.1

Option 3: Use 1.5 mm (0.06 inch) SDH position A refer to Illustration 6 / Image 1.19.1. An attenuation factor for indication interpretation will have to be used to compensate for attenuation of the sound-beam as the sound beam propagates through the material. Reference AWS D1.1 or equivalent code or standard for further instruction.

Image1.20.1

Image1.20.2

Option 4: Cat? t Notch Blocks: Blocks the same material and thickness as the parts to be tested. Electrical Discharge Machining 1 mm (0.04 inch) Notch?s at 1/4t and 1/2t depths.
Use the dimensions in Illustration 7 / Image 1.20.2 in order to fabricate Cat? t Notch Blocks use ASTM A572 Grade 42/50 steel.

**Sample Surface Preparation**
The surface shall have contour allowing the close coupling between the search unit and scanning surface.

The inspection surface shall be free of loose scale, loose paint, weld spatter, dirt, excessive roughness, or other foreign objects that would interfere with the transmission of sound energy from the search unit into the part. Cleaning and/or grinding may be needed.

**Test Procedure**
In addition to the annual UT equipment certification/qualification, periodical calibration or standardization is required to verify that UT equipment is performing as intended for day-to-day usage.

**Angle Beam Calibration**

Calibration: The distance and sensitivity calibration shall be verified by the UT operator.

Re-calibration shall be made a minimum of every 4 hours or process change, such as changing operator, search unit or cable, battery, and re-couple search unit.

Verify the Beam Index Point: (The following example is conducted on an IIW Type Block.) Position the UT probe toward the 100 mm (4.0 inch) radius on the IIW-type reference block.

Set proper range in the instrument to ensure that the signal from the 100 mm (4.0 inch) radius is displayed. Scan the search unit back and forth to peak the 100 mm (4.0 inch) signal. The point on the search unit wedge aligning with the 0 reference line on the calibration block is the beam index/entry point (position D in Illustration 2 / Image 1.16.1).

Verify the Beam Angle: Position the search unit toward the Lucite/open window on the IIW-type reference block.

Set proper range in the instrument to ensure that the signal from the Lucite/open window is displayed. Scan the search unit back and forth to peak the signal.
The angle marked on the reference block in line with the search unit index point is the actual beam angle. The beam angle tolerance shall be within +/- 2?. Depending on the beam angle and the type of reference block, other techniques recognized by related industrial standards may be used (position B or C in Illustration 2 / Image 1.16.1).

Distance Calibration: In order to ensure the accuracy of locating weld discontinuities, the distance shall be calibrated through the entire sound path used during the specific examination.

100 mm (4.0 inch) radius on the IIW-type reference block is commonly used for distance calibration in angle beam applications (position D in Illustration 2).

Position the UT probe toward the 100 mm (4.0 inch) radius. Set the proper range in the instrument to ensure the second reflection from the 100 mm (4.0 inch) radius can be displayed.

In order to obtain meaningful readings, other instrument settings, such as probe angle, gate and gain level shall be properly selected.

**Sensitivity Calibration**
1.5 mm (0.06 inch) side-drilled-holes (SDH) parallel to the inspection surface and perpendicular to the sound path shall be used as the calibration target for send/receive probes. For pitch/catch dual probes a 1mm (inch) flat bottom notch shall be utilized

DAC/TCG - DAC (distance-amplitude-correction) or TCG (time corrected gain): The signal from the 1.5 mm (0.06 inch) SDH should be calibrated to be 80% FSH (full-screen height) for the first point of a DAC curve and all points for the TCG. DAC and TCG shall be used to ensure the same inspection sensitivity at different sound paths across the entire range.

Minimum of three points shall be used to establish the DAC/TCG, over the entire range and a full skip distance for the material thickness being tested.

Use Sensitivity Calibration Blocks Option 1 or Option 2 described in the ""Sensitivity Calibration Blocks" " section.

Example for DAC/TCG set-up for a 75 mm (3.0 inch) thick weld joint using 45? wedge using the Cat? DAC Block use the 30 mm (0.40 inch), 60 mm (2.40 inch), and 120 mm (4.80 inch) holes.

Example for DAC/TCG set-up for a 16 mm (0.60 inch) weld joint using 70? wedge using the Cat? t block. Use the 1/4t hole, 3/4t hole, and the 7/4t hole.

Reference Reflector: When a single 1.5 mm (0.06 inch) Reference Reflector (refer to AWS D1.1) is used to attain a horizontal reference-line height indication. The maximum dB level used to obtain an 80% FSH peak signal shall be recorded as the Reference Gain Level.

An attenuation factor for indication interpretation will have to be used to compensate for attenuation of the sound beam as the sound beam propagates though the material. An Indication Rating should be calculated for the basis of Acceptance or Rejection. Use Sensitivity Calibration Block Option 3 position A in Illustration 6.

**Scan Pattern, Scan Distance, and Scan Speed**

Image1.26.1

Send/Receive search unit inspections - the entire volume of weld and HAZ (heat affected zone) shall be examined from each side of the weld wherever practical. Examination shall be made in the first and second leg wherever possible. Scan speed shall be less than 150 mm (6.0 inch) per second unless the inspection procedure specifies differently. (Illustration 9 / Image 1.26.1)

In order to detect longitudinal discontinuities. The search unit shall be oscillated to the left and right with an angle of approximately +/- 15? while continuously scanning perpendicularly to the weld axis. The lateral movement advancing the search unit shall not exceed 75% of the search unit width.

In order to ensure full volume coverage with angle beam inspections. The scan distance shall cover at least 1 full skip path (first and second leg) back from the weld center line. To detect transverse discontinuities, the sound beam shall be directed at approximately 15? parallel to the weld axis. The search unit shall be moved along the weld edge from both sides and from opposite directions.

**Initial Surveillance Scanning**
For initial scanning, extra gain (6dB or 12dB) may be required in order to facilitate detection of potential discontinuities. The evaluation of the indication shall be performed at the appropriate reference sensitivity.

**Probe Selection**

Image1.28.1

Refer to the D11 UT Inspection Areas section below for thickness and probe selection instructions for each weld joint. Table 1 shall be used for reference if needed. Alternate angles can be used for multiple thicknesses if warranted by joint design or joint preparation.

**Accept/Reject Criteria and Sizing**

Image1.30.1

Note: Adjacent discontinuities: when (AE) is smaller than the designated minimum length (AE) < (L1) or a specific length), the two discontinuities shall be regarded as continuous and the overall length is (L1) + (AE) + (L2).

Subsurface internal weld quality will meet the requirements set forth by this document. In order to determine the rejectable lengths of indications that meet or exceed the following thresholds:
1.) A -6dB offset shall be applied to any DAC or TCG. Indications that meet or exceed this offset threshold are rejectable.
2.) A +6dB Indication Rating for 0dB reference level shall apply. Indications that meet or exceed this indication rating are rejectable.

The above thresholds are created from 1.5mm (0.06 inch) SDH sensitivity reference point/s. These point/s are considered the reference level. The above sensitivity thresholds are created by reducing the rejectable indication size by 50% from the reference level.

An indication that meets or exceeds the -6dB offset threshold level for DAC or TCG OR a +6dB indications rating for 0dB reference level continuously for 12 mm (0.5 inch) or 17 mm (0.67 inch) aggregate length is rejectable.

Intermittent indications that do not meet the criteria but the aggregate length of the indications exceed 17mm (0.67 inch) of total length is considered rejectable. Indications below 5 mm (0.20 inch) in length are not typically included in the aggregate indication length.

In determining the ends of rejectable indications, the 6dB drop method shall be used, with the flaw detector sensitivity set to the reference level (0dB). Move the search unit parallel to the weld until the tip of the signal drops to 50% of the DAC height. Mark the weld even with the center of the search unit. Move the search unit parallel to the weld in the opposite direction until the signal drops to 50% of the DAC height. Mark the weld even with the center of the search unit. Acceptability of welds with multiple defective areas. If the space between two defective areas is less than the largest defect length, the area between the two defective areas shall be considered rejectable and should be marked for repair. Refer to Illustration 10.

**D11 UT Inspection Areas**
During In-Service Field Inspection: UT inspection is required on welds in Location A and B per Illustration 11. Both 45? and 70? send/receive conventional angle beam inspection. These methods are described below.

Image1.32.1

Image1.32.2

Image1.32.3

Inspect weld joints A and B (Illustration 11 / Image 1.32.1) with 45? and 70? send/receive transducer search units.

The Send/Receive transducer search units in both 45? and 70? shall be utilized for inspection. The transducers shall be scanned in both directions from the centerline of the weld where possible. Follow the Scan Pattern, Scan Distance, and Scan Speed and Accept/Reject Criteria and Sizing sections for determining if the welds are acceptable. The thickness of the instrument should be set to 75mm (3 inch) nominal rail thickness. The 70? should be used strictly as a first leg inspection. As the scan distance from the edge of the weld will be approaching 250mm. The 45? search unit should be scanned at minimum 150mm (6 inch) back from the edge of the weld for full weld volume coverage. (Illustration 13 / Image 1.32.2)

Inspect weld joints E and F (Illustration 11) with 70? send/receive transducer search unit. The transducer shall be scanned forward and backward from the plate side weld toe where possible. Follow the Scan Pattern, Scan Distance, and Scan Speed and Accept/Reject Criteria and Sizing sections for determining if the welds are acceptable. The thickness of the instrument should be set to 20mm (0.79 inch) nominal plate thickness. The 70? search unit should be scanned at minimum 120mm (4.75 inch) back from the toe of the weld for full weld volume coverage. (Illustration 14 / Image 1.32.3)

**Mark for Weld Repair**
To repair the rejected weld, additional excavation length at each end of the rejectable discontinuity is normally required. A general guideline is to mark an additional 25 mm (1.0 inch) to 50 mm (2.0 inch) on both ends of the discontinuity in order to ensure proper removal of defective areas. This guideline shall be followed wherever practical.

**Final Inspection Reporting**
After the NDE inspections are completed the inspection result should be recorded. For VT and MT indications an overview picture of the area of interest and a close-up picture with a scale is required with a short description matching the weld locations from Illustration 1 or 11. For UT inspection that are completed, fill out the form provided in Table 2 or equivalent form. A copy of these reports should be provided to the Customer, Dealer, and/or the appropriate Caterpillar product support representative.

INSPECTION INTERVALS
Inspections of the frame assembly for cracks should be conducted during regular maintenance intervals. Areas to be inspected are blocked by one or more components. If the component that is blocking the frame is removed, an inspection of that area should be performed. Take advantage of the opportunity to inspect those parts of the frame assembly that are exposed whenever components are removed.