Usage:
March 21, 2005
U-92
D-79
O-81
After failure only |
PRODUCT SUPPORT PROGRAM FOR REPAIRING SWINGFRAME CRACKS AT THE BOOM CYLINDER MOUNTS ON CERTAIN 5110B EXCAVATORS |
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| 6506 7051 |
PS50926
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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.
TERMINATION DATE
March 31, 2007PROBLEM
The swingframe may crack where the boom cylinder mounts on certain 5110B Excavators. The crack initiation point is on the boom cylinder outer ears or mounting plate. The cracks can be repaired and reinforcement plates can be added.AFFECTED PRODUCT
| Model | Identification Number |
| 5110B | AAA344-369 |
| 5110B | AAK222-231 |
| 5110B | AAT312 |
PARTS NEEDED
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| 2 | 1845702 | BOSS |
| 1 | 2633333 | PLATE |
| 1 | 2633334 | PLATE |
| 1 | 2633335 | PLATE |
| 1 | 2633336 | PLATE |
| 2 | 2633337 | PLATE |
| 2 | 2635831 | BOSS |
ACTION REQUIRED
See the attached procedure and machining dimensions.SERVICE CLAIM ALLOWANCES
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PARTS DISPOSITION
Handle the parts in accordance with your Warranty Bulletin on warranty parts handling.Attach. (1-Rework Procedure)
(2-Machining Dimensions)
REWORK PROCEDURE
PRELIMINARY
Welder Qualification/Safety
All welders must be qualified for fillet and groove welding as outlined in the current ANSI/AWS D1.1, or D14.3, or Caterpillar Manufacturing Practice MC1000-105. The welding operator must also have used the welding process during the last six months or be re-certified for this process before welding. Personal protection should be provided to assure that total weld fume in the operators breathing zone is within safe limits.
Electrode /Characteristics
The SMAW process shall be used with E7018 (ANSI/AWS A5.1) welding electrode. The weld deposited by these electrodes will have the following minimum mechanical properties:
| TENSILE STRENGTH | 480 MPa (70 KSI) |
| YIELD STRENGTH | 400 MPa (58 KSI) |
| ELONGATION | 22% |
| IMPACT TOUGHNESS | 20 FT LBF @-20F (27J @-18C) |
These are low hydrogen electrodes and must be stored in an electrode oven at 120 degrees C (250 degrees F) when not in use. If the electrodes get damp, scrap or recondition to manufacturer's specifications.
The following chart relates to the electrode diameter and approximate current settings for welding:
| DIAMETER | AMPS |
| 3.2MM (0.125") 1/8" | 70-140 |
| 4.0MM (0.156") 5/32" | 110-180 |
| 4.8MM (0.166") 3/16" | 190-270 |
Use the direct current electrode positive (DC reverse polarity) polarity setting and remove the slag after every pass. The weld pass shall not exceed two times the electrode diameter.
As an alternative process the FCAW process
may be used with E71T-1 (ANSI/AWS A5.20) welding electrode and the manufacturers
specified shielding gas(es). The weld deposited by these electrodes will
have the following mechanical properties:
| TENSILE STRENGTH | 480 MPa (70 KSI) |
| YIELD STRENGTH | 400 MPa (58 KSI) |
| ELONGATION | 22% |
| IMPACT TOUGHNESS | 20 FT LBF @-20F (27J @-18C) |
Welding parameters will vary due to weld position
and manufacturer of the welding electrode. For 1.3mm (0.052 inch) diameter
electrode typical welding parameters should be:
| WIRE FEED SPEED | VOLTAGE | APPOX. AMPERAGE |
| MIN 200 IMP | 24 | 210 |
| OPT 275 IMP | 28 | 250 |
| MAX 325 IPM | 29 | 300 |
Use the direct current electrode positive (DC reverse polarity) setting and remove the slag after every pass.
PRECAUTION/PRECLEANING
When the base metal temperature is below 32 degrees F, the base metal shall be preheated to at least 70 degrees F (unless otherwise specified) and this minimum temperature maintained during cutting or welding.
Clean the area to be welded of oil, grease, paint, and dirt. Attach the welding ground cable directly to the frame assembly. Protect all machined surfaces from sparks or spatter produced by the welding, chipping, and/or grinding operations.
QUALITY/INSPECTION
The weld shall be free from cracks, porosity, undercut, and incomplete fusion. All weld quality shall conform to ANSI/AWS 14.3 or Caterpillar Engineering Specification 1E99. All groove welds are to be ultrasonically inspected to factory specs.
There are two keys to the success of this weld procedure:
1- Proper cleaning and preparation of the base material
2- Proper blending of each finished weld toe such that stresses properly transfer
Procedure
1- Using the air carbon arc gouging process remove the cracked welds in the region indicated in Figure 1. Reweld.
2- Measure the distance between the ears at each cylinder mount. Create three spacers (should be aprox. 173mm) for each cylinder mount to be used to place and hold the replacement ear in position during welding. Using an oxy-fuel torch and/or air carbon arc torch remove the 207-2933 ears indicated in Figure 2. Ensure the adjoining plates are not damaged in the process. The ears are expendable.
3- Clean the surfaces where the new ear is to be placed ensuring that no slag, scale, paint, rust, grease or water remains.
4- Use the two remaining ear's bores and the spacers created in the second step to locate and tack the 263-3337's (replacement larger sized ears). See Figure 4.
5- See Figure 5. Weld the ears in place. Weld from the top up of the ear upwards and alternate sides with each set of passes in order to minimize distortion.
6- Locate and tack the plates as seen in figure 6. Ensure the center lines are in alignment with the center lines of it's corresponding ear.
7- Weld the 263-3336. See Figure 7. Leave either lower corner of each gusset un-welded to allow for water drainage.
MACHINING DIMENSIONS
