993K Wheel Loader Tilt Cylinder Cap Weld Rework Procedure{0679, 5104} Caterpillar

993K Wheel Loader Tilt Cylinder Cap Weld Rework Procedure{0679, 5104}

Usage:

993K Z9K

Wheel Loader:: 993K (S/N: LWA1-UP; Z9K1-UP)

Introduction

This Special Instruction provides the welding guidelines and the rework procedure for the dealer weld repair of the 993K Wheel Loader tilt cylinder cap.

Do not perform any procedure in this instruction or order any parts until you understand the information that is contained in this instruction.

Guidelines for Dealer Weld Repair

Remove existing weld using a lathe until all discontinuities have been removed. The complete weld will not need to be removed, unless discontinuities are in the root.

Ensure that joint consists of two J-grooves, joined to make a U-groove and each J-groove has a radius of 4 mm (0.16 inch), with 15 degree sidewall to accomplish a 30 degree included angle, if possible. Do not make included angle smaller than 30 degrees.

Before welding and regardless of the welding process, ensure joint and consumables are free of contamination. Ensure that preventative maintenance has been performed on welding equipment. Ensure that there are no wire feed restrictions, tip is in good condition and flux is dry. Ensure that the ground cable is not frayed and is securely fastened.

Utilize the Sub Arc (SAW) process if possible to make weld repairs. Electrode diameter should be no greater than 3/32. Utilize Lincoln L-61 and Lincolnweld 860 flux. Consult manufacturers recommended settings (as a reference point) to determine parameters.

If SAW is not an option, utilize the Gas Metal Arc (GMAW) process. Recommend a 90% AR/ 10% Co2 gas mix. Ensure that gas flow is between 35 and 45 Cfh. Electrode diameter is no greater than .045", and electrode is an ER70-S3 (Recommend Lincoln Electric L-50). Consult manufacturers recommended settings (as a reference point) to determine parameters.

Ensure nozzle, tip, and diffuser are clean and in good condition and gas flow is not restricted.

Regardless of process, ensure that wire is coming out straight and positioned at center of root for the first pass.

Do not utilize a weave for the root pass.

Adjust torch work and travel angles and weave as required to ensure that complete fusion and no undercutting is present.

Clean and inspect the weld after each pass. Ensure that there are no slag, undercut, lack of fusion, or porosity present and that profile does not exhibit excessive concavity or convexity.

Layer weld passes as required to ensure a strong and integral weld that completely fills the groove joint without exhibiting excessive concavity or convexity.

Visually inspect weld for surface discontinuities.

Allow weld to cool to ambient temperature. Do not quench or accelerate the cooling process in any way other than using forced air if desired.

Inspect completed weld by Ultrasonic (UT) or Radiographic (RT) to ensure that weld conforms to the applied acceptance criteria.

Tilt Cylinder Cap Weld Rework Procedure

Obtain a Cylinder with a cracked Cap weld. If possible, utilize a Cylinder Assembly that has not been weld repaired prior to rework.

Remove paint at least 50.8 mm (2 inch) on either side of the Cap weld. Removing the paint will reduce possible weld site contamination and enhance visual inspection of area to be reworked.

Cut out Cap weld on a lathe.

Measuring from the flange end of the Cylinder Assembly, determine the original Tube length prior to welding. Mark this dimension on the outside of the Cylinder Assembly.
Note: Original length of Cylinder Assembly from flange face to center of weld is 1204 ± 0.5 mm (47.4 ± 0.02 inch).

Cut out the Cap weld starting from the center of the weld. Cut the weld down to the point where the weld just begins to penetrate the Cap weld backing strip.
Note: The original Tube thickness is 22.2 mm (0.87 inch). Take care not to cut too deep into the weld backing strip. Cut slowly after 21 mm (0.83 inch) until line of separation begins to appear. Do not go beyond line of separation.

Separate the Tube from the Cap, taking care not to damage either component.

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Illustration 1	g02321836
(AA) Current (BB) After machining (A) 190 ± 0.5 mm (7.48 ± 0.02 inch) (B) 223 ± 0.5 mm (8.78 ± 0.02 inch)

Machine the Cap to new dimensions.

Machine Cap weld "Backing Strip" from an Inside diameter of 190 mm (7.48 inch) to a new Inside diameter of 223 mm (8.78 inch). This process should leave a backing strip thickness of 6 mm (0.24 inch). Refer to Illustration 1.

Machine proper "J-Groove" in Cap maintaining as much of the original length as possible.

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Illustration 2	g02321839
Location of tack strips

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Illustration 3	g02321841
Example of tack strip

Weld a "Tack Strip" in four quadrants. Tack Strips should not exceed 25.4 mm (1 inch) in length on the reworked cap. Refer to Illustration 2 and Illustration 3.

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Illustration 4	g02321842
(C) 335 mm (13.2 inch) (D) 10 ± 0.25 mm (0.394 ± 0.010 inch)

The Tack Strip will be machined to the correct dimension. The machine process will properly space the cap and tube to the correct overall length of the cylinder assembly.
Note: Original Pin Center to Face of "J-Groove" is 335 ± 0.5 mm (13.19 ± 0.02 inch) with an additional 10 ± 0.25 mm (0.39 ± 0.010 inch) to face of backing strip. Refer to Illustration 4 and Illustration 7.

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Illustration 5	g02321844
(E) Calculated dimension to maintain 1539.0 ± 0.5 mm (60.59 ± 0.02 inch) overall length with cap and tube assembled (TS) Tack strip machined back to compensate for material lost during machining process

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Illustration 6	g02321846
Tack strip after machining J-Groove and Assembly

Machine "Tack Strips" in order to maintain original overall dimension of Cylinder Assembly.
Note: When the "Tack Strips" are properly machined, the Cap can be seated on the Tube and the overall Cylinder Assembly will be the proper length within 0.5 mm (0.02 inch). Refer to Illustration 5 and Illustration 6. Refer also to Illustration 10 for the 1539.0 ± 0.5 mm (60.59 ± 0.02 inch) dimension.

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Illustration 7	g02321847
Example of the J-Groove shown on the cap, the J-Groove on the tube will be a mirror image (F) 15 Degree (G) 4 mm (0.16 inch) Radius

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Illustration 8	g02324234
(F) 15 Degree (G) 4 mm (0.16 inch) Radius (H) 1204.0 ± 0.5 mm (47.40 ± 0.02 inch)

Machine "J-Groove" in Tube, maintaining as much of the original 1204 ± 0.5 mm (47.40 ± 0.02 inch) overall length of the Tube as possible. Refer to Illustration 7 and Illustration 8.

Using an approved Dye Penetrant or Magnaflux procedure, check the weld grooves on both the Cap and Tube prior to rewelding.
Note: Any cracks must be removed prior to welding. Use Salvage and Reuse Guideline to determine whether to scrap.

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Illustration 9	g02321853
(CC) Head bolt alignment for 309-0856 Cylinder As used in 308-0835 Tilt Cylinder Gp and 308-0832 Tilt Cylinder Gp (DD) Head bolt alignment for 309-0834 Cylinder As used in 308-0837 Tilt Cylinder Gp and 308-0833 Tilt Cylinder Gp (J) Port location (K) Position of missing holes (L) Cap pin bore to be perpendicular to these head bolt holes

Assemble Tube to Cap and align properly.

Press the cap onto the tube, seating the tube on the machined shoulder of the "Tack Strips". Take care to align the Cylinder Assembly as shown in Illustration 9 to assure that the Cylinder Assembly can be properly reinstalled on the machine.

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Illustration 10	g02321858
(M) 1539.0 ± 0.5 mm (60.59 ± 0.02 inch)

Measure overall length from Flange Face to the Pin. Confirm that this dimension is 1539 ± 0.5 mm (60.59 ± 0.02 inch). Refer to Illustration 10.

Ensure that joint consists of two "J-Grooves", joined to make a "U-Groove", and that each "J-Groove" has a radius of 4 mm (0.16 inch), with a 15 degree sidewall to accomplish a minimum included angle of 30 degrees. Do not make included angle less than 30 degrees.

Weld Cap to Tube

After the tube and cap have been properly aligned and spaced (or gapped), reweld the tube to the cap. Weld in accordance with Caterpillar Salvage and Re-Use Guidelines. The guidelines are published in SIS Web (Caterpillar Service Information System) Special Publication, SEBF8072, except for the following recommended Sub-Arc (SAW) or Gas Metal Arc (GWAW) welding procedures.

Sub-Arc Welding (SAW) is the preferred method however Gas Metal Arc Welding (GMAW) is also acceptable.

Pre-Heat surfaces to be rewelded to 176.7° C (350° F).

SUB-ARC (SAW) PROCESS

Before welding, ensure weld joint and consumables are free of contamination. Ensure that preventative maintenance has been performed on welding equipment. Ensure that there are no wire-feed restrictions, tip is in good condition and flux is dry. Ensure that wire is coming out of tip straight and is centered in the root of the joint for first pass. Ensure that ground cable is not frayed and is securely fastened.
Electrode should be no greater than 3/32" in diameter in order to ensure access to root. Utilize Lincoln L-61 Electrode and LincolnWeld 860 Flux. Consult manufacturers recommended settings as a reference point for determining optimal settings.

Do not utilize weave for first pass.

Adjust torch work and travel angles in order to weave as required to ensure complete fusion and that no undercutting is present.

Clean and inspect the weld after each pass. Ensure that there is no slag, undercut, lack of fusion, or porosity present. Ensure that the profile does not exhibit excessive concavity or convexity.

Layer weld passes as required to ensure a strong and integral weld that completely fills the groove without exhibiting excessive concavity or convexity.

Allow weld to cool to ambient temperature. Do not quench or otherwise accelerate the cooling process other than forced air if desired.

Inspect completed weld by either Ultrasonic (UT) or Radiographic (RT) methods to ensure that weld conforms to the applied acceptance criteria.

GAS METAL ARC (GMAW) PROCESS

Use a recommended 90% AR /10% CO2 gas mix (92% AR / 8% CO2 is also acceptable).
Before welding, ensure weld joint and consumables are free of contamination. Ensure that preventative maintenance has been performed on welding equipment. Ensure that there are no wire-feed restrictions. Ensure that the nozzle, tip, and diffuser are clean and in good condition. Ensure that gas flow is not restricted. Ensure that wire is coming out of tip straight and is centered in the root of the joint for the first pass. Ensure that the ground cable is not frayed and is securely fastened.
Ensure that gas flow is between 35 and 45 CFH. Ensure that electrode diameter is no greater than 0.045", and electrode is an ER70-S3 (Recommend Lincoln L-50 electrode). Consult manufacturers recommended settings as a reference point for determining optimal settings.

Do not utilize weave for first pass.

Adjust torch work and travel angles in order to weave as required to ensure complete fusion and that no undercutting is present.

Clean and inspect the weld after each pass. Ensure that there is no slag, undercut, lack of fusion, or porosity present. Ensure that the profile does not exhibit excessive concavity or convexity.

Layer weld passes as required to ensure a strong and integral weld that completely fills the groove without exhibiting excessive concavity or convexity.