WASHER 2239750 - Caterpillar

This is a 16.0-hour job
PARTS DISPOSITION
Handle the parts in accordance with your Warranty Bulletin on warranty parts handling.
Rework Procedure
Two methods can be used to repair the weld.
First, the preferred method is a TIG dressing. The second method can be performed in an emergency. This method does not require an experienced welder or specialized equipment.
METHOD 1
TIG DRESSING OF FILLET WELDS FOR IMPROVED FATIGUE LIFE
The equipment required is as follows.
- GTAW (TIG) Power Supply and torch capable of 225 amps (min. 60% duty cycle) with hand/foot current control.
- Shielding gas ? 100% Argon (& flow meter)
- Electrode ? Lanthanated, Ceriated or Thoriated Tungsten [3/32? (2.4 mm) dia.]
ER70S-2 filler metal (1/16? dia.) if needed
- Grinder - Pneumatic or Electric with Carbon Steel Wire Wheel Attachment
- Aluminum oxide grinding wheel to sharpen tungsten electrode.
- Radius Gages
The first steps to ensure a proper TIG dressing are cleanliness and tungsten electrode preparation. The fillet weld and surrounding base metal must have all contaminants thoroughly removed. It is imperative that all rust, dirt, oil, scale, silicate islands, etc. are non-existent. This can be accomplished quickly via a grinder with a carbon steel wire attachment. Next, prepare a 3/32? (2.4 mm) tungsten electrode to the dimensions shown in Image 1.3.1. Grinding striations should run parallel not transverse.
Image1.3.1
Adjust shielding gas flow rate to 15 CFH and current control to approx. 225 amps. If a ramp down control is present on the power source, utilize to ensure proper crater fill control.
A number of different techniques exist for TIG dressing. This is due to the variability of the contour of the fillet weld toe that must be re-shaped. Therefore, either a stringer or weave manipulation of the torch can be employed so long as the goal of a smooth, contoured radius of 5 mm minimum exists between the base material and weld metal.
Note 1: 10 to 15 deg push angle for both stringer and weave
Note 2: Poorly shaped fillet welds with 70 ? 90 degree transition angles to the base material will probably require several overlapping TIG dressing runs to properly smooth out the weld toe transition region.
Note 3: TIG dressing can be conducted in the vertical position as long as it is performed in a DOWNHILL progression.
Note 4: If undercut or other circumstances require the addition of filler metal, this can be accomplished by hand feeding ER70S-2 (1/16? dia.) into the weld pool and then repeat the TIG dressing to achieve desired toe radius/profile.
Image1.5.1
Image1.5.2
Once TIG dressing is completed and the area is allowed to cool area needs to be cleaned and painted to prevent pitting due to corrosion.
Image1.6.1
METHOD 2
BURR GRINDING OF FILLET WELDS FOR IMPROVED FATIGUE LIFE
The equipment required is as follows.
- High speed hand-held pneumatic rotary pencil grinder ? 20,000 rpm min.
- Compressed air ? 90 psi min.
- Tungsten carbide burr (conical shaped) with an end diameter of approx. 10 mm.
- Leather welding jacket, leather gloves, safety glasses and face shield to protect operator from metal slivers.
- Radius gauges and bridge cam gauge for inspection.
Image1.7.1
Image1.7.2
Burr tip should