LATCH AS 3714271 - Caterpillar

Table 1
Process    U.S. Standard    European Standard    
GMAW     AWS A5.18 E70S-3 or E70S-6     EN440 G42 4 M G3Si1    
FCAW     AWS A5.20 E71T-1 or E71T-5     EN758 T46 0 R C 3 H10    
MCAW     AWS A5.18 E70C-6M H4     EN758 T46 3 M M 2 H5     Semi-automatic welding requires a gas shield, so air turbulence must be avoided. Follow the recommendations of the wire supplier concerning the shielding gas.All repairs must be done in a controlled environment to prevent rapid cooldown of the weld. A controlled environment would be inside a repair shop.Note: Do not weld in windy conditions. Do not weld when the temperature is below 16° C (61° F), as the weld will be more likely to crack.Penetration characteristics may vary depending on the electrode diameter, shielding gas, welding current, and plate thickness. The geometry of the welded joints, surface conditions, composition of the base metal, and the electrode will affect the welds.All welds should be done in the horizontal or flat position to ensure a smooth surface finish.Welds must be free of any undercuts or notches. Those are stress raisers. Grind the surface smooth on the repaired structure to eliminate stress. A smooth transition between the weld and the plate should be maintained.Preparing the Metal for Welding
All grease, water, paint, rust, dirt, and scale must be removed before welding. Any of these materials will discharge gas and cause porosity in the weld deposit. Water and rust will cause hydrogen embrittlement, which causes cracks in the weld deposit.Remove paint, rust, dirt, and scale with a wire brush, or by buffing or grinding. Shot blasting all work areas will also remove foreign material.Remove any oil or grease on the boom with a Caterpillar approved solvent.Before welding on the boom, remove all foreign material and paint a minimum of 50 mm (2 inch) beyond the area of the weld.Cover all finished bores and threads. Finished bores and threads must be protected from foreign material, welding, gouging, and paint spatters.Prepare the Machine for Servicing
Move the machine to level ground. The ground must support the weight of the machine. Personal injury or death can result if the surface below the machine cannot support the weight of the machine.
Illustration 4 g02658436
Servicing position of an Excavator
Put the machine in the servicing position. The bucket must rest flat on the ground after the boom is lowered.
With the machine in the servicing position, remove the bucket from the stick. Refer to the Disassembly and Assembly Manual for the systems on your machine.
Remove the stick from the boom. Refer to the Disassembly and Assembly Manual for the systems on your machine.
Position the boom on the ground. Refer to the Disassembly and Assembly Manual for the systems on your machine.
Move the control levers for the boom, the stick, the bucket, swing operation, and the left and right travel to the full stroke positions. This movement will release any actuator pressure in the hydraulic lines.
Move the hydraulic activation control