SERVICE WELDING GUIDE Caterpillar

Safety Precautions

* Keep equipment and work area clean, dry and neat. Put tools away when you are through using them.

* Be sure work area has adequate ventilation.

* Always wear protective gloves and aprons, safety shoes and heavy cotton clothing. Keep collars and shirt cuffs buttoned. Turn trouser cuffs down. Be sure trouser legs extend below shoe tops.

* Wear a welding helmet or eye shield with proper filter plates when welding or cutting. Use a No. 4 or No. 5 filter for torch brazing, flame cutting and gas welding. Use a No. 10 or No. 12 filter for arc welding.

* Keep a CO₂ or dry powder fire extinguisher within reach-especially when flame cutting or welding on or near tractors, engines, etc.

* Remove all flammable materials, volatile liquids and explosive gases from the welding area or shield them adequately.

* Do not weld or cut on containers such as drums, barrels and tanks until you know there is no danger of fire or explosion from their contents.

* Always drill a relief hole in a closed compartment, such as a front idler or track roller frame box section, before welding or cutting on it. If this is not done, any moisture inside the compartment can vaporize, causing an extremely high pressure inside the compartment which may lead to an explosion.

* Never strike an arc on a cylinder of compressed gas or on any part of a track adjusting mechanism.

* Be sure welding cables, electrode holders and clamps are in good repair and properly insulated.

* Support large machine components such as scraper bowls and aprons, bulldozer blade, etc. solidly before working under them.

* Fasten oxygen an acetylene hoses cylinders securely in the vertical position before using. Observe all safety rules for handling compressed gas cylinders.

* Keep oxygen and acetylene hoses from being cut or burned. Inspect oxygen and acetylene hoses periodically for leaks and worn places. Check all connections for leaks before igniting flame. Do not use oil on oxygen fittings.

* Provide mechanical air movement over coated or painted surfaces being welded to dispel any toxic fumes that may be produced.

Other Recommended Equipment

Pneumatic Vibrator for slag removal

* Either chisel or needle type

Grinder, pneumatic or electric

* 7 inch or 4 inch diameter - 36 grit and/or 24 grit

* Both cup grinder and disc grinder

* Cat part #9U-6241 Electric

* Cat part #1U-5946 Pneumatic

Electric Rod Oven for electrode storage if using shielded metal arc

* A practical approach is to use an airtight container with at least a 100 watt light bulb permanently turned on.

* An old refrigerator with sealing door is perfect

* Refer to Publications section for purchasing information.

Liquid penetrant kit for surface crack detection on ferrous and non-ferrous metals

* Cat part #4C-4763 aerosol

* Cat part #9U-6335 non aerosol

Arc-Air for removing defective welds

* 3/8 inch and/or 1/4 inch carbon round or semi-round electrodes

* Use dry air supply, no lubrication present

Oxyacetylene outfit with cutting and heating heads

* Cat part #1U-6469 heavy duty Oxy-acetylene

Tempilstick crayons for determining temperature of metal

* Refer to publications section for purchasing information

Leather weld clothing for operator

* Cat part #1U-6583 Leather Gloves

* Cat part #1U-6579-80 Leather Coat

* Apron or chaps

Ceramic Weld Backing Material

* Cat part #1U-7767 Grooved

* Cat part #1U-7768 Round

* Cat part #1U-7769 Triangle

Power Supplies and Electrodes

If Stick Electrode (SMAW) Shielded Metal Arc Welding

* 400 to 600 Amp DC power source is recommended

* E7018 electrode

If Semi-Automatic (FCAW) Flux Cored Arc Welding

* 400 to 450 amp power source is recommended

* Shielding gas 75% argon 25% CO₂

* E71T-1 flux cored wire Cat part #9U-6652

If Semi-Automatic (GMAW) Gas Metal Arc Welding

* 400 to 450 amp power source is recommended

* Shielding gas 75% argon 25% CO₂ first choice, and straight CO₂ second choice

* (AWS) ER70S-3 solid wire Cat part #1U-5368

Considerations when using (GMAW) Gas Metal Arc Welding

Base metal cleanliness is more critical when using GMAW than when using SMAW. The fluxing compounds present in SMAW cleanse the molten weld deposit of oxides and gas forming compounds. Such fluxing slags are not present in GMAW.

GMAW is a gas shielded welding process and porosity may occur if too much or too little gas shielding flow is used. The gas shield can also be blown away by air movement, or by fans running in the welding area. The welder must not have too much or too little distance from the welding gun to the piece being welded. These are variables to consider when deciding whether to use GMAW or SMAW.