1999/02/22 Caterpillar

All Models

Read and understand the manufacturer's instructions and your employer's safety practices. Keep your head out of the fumes. Use ventilation, exhaust at the arc, or both, to keep fumes and gases from your breathing zone and general area. Wear correct eye, ear, and body protection. Do not touch live electrical parts. See American National Standard Z49.1 "Safety in Welding and Cutting" published by the American Welding Society, 2501 N.W. 7th Street, Miami, Florida 33125: OSHA Safety and Health Standards, 29 CRF 1910, available from U.S. Dept of Labor, Washington, D.C. 20408.

NOTE: Welding operator personal protection should be provided to assure that total weld fume in the operators breathing zone does not exceed OSHA limits. All repair welding operators must be qualified for groove and fillet welding, as outlined the current ANSI/AWS D14.3, or Caterpillar Manufacturing Practices MC1000-105. The qualification will be for the SMAW (Shielded Metal Arc Welding) process in the vertical welding positions. The welding operator must also have used this welding process during the last six months or be re-certified for this process before welding. Documentation must be maintained of the weld operators qualifications. The alternate process for this repair could be FCAW (Flux Cored Arc Welding). The area to be welded and the surrounding area must be at a minimum temperature of 16°C (60°F) before and during welding.

NOTE: The following information and weld parameters does not apply to high stressed areas or steels that require special welding procedures such as preheat, post heat, or special weld electrode and parameters. For steels that require special welding applications contact Caterpillar Weld Engineering Department.

Use the direct current electrode positive (DC reverse polarity) polarity setting and remove the slag after every pass. The weld pass size shall not exceed two times the electrode diameter. As an alternate process the FCAW process may be used with E71T1 (ANSI/A5.20) welding electrode and the manufacturer's specified shielding gas(es). The weld deposited by these electrodes will have the following mechanical properties:

500 MPa (72 KSI) Tensile Strength

420 MPa (60 KSI) Yield Strength

22% elongation to 50 mm (2 IN)

27 J (20 ft. lb) Notch Toughness at -18°C (0°F)

NOTE: This type of electrode has limitations if it is used to carry larger weld pass volumes in the flat welding position. Due to the fast freezing characteristics of this electrode slag system, there is a chance of trapping evolving gases in the weld melt. Precaution should be taken by controlling weld pass size. Welding parameters will vary due to weld position and manufacturer of the welding electrode. For 1.30 mm (.052 IN) diameter electrode typical welding parameters should be:

Use the direct current electrode positive (DC reverse polarity) polarity setting and remove the slag after every pass. The weld pass size shall not exceed 8.0 mm (.031 in) fillet volume. Clean the frame of oil, grease, paint, and dirt in the area to be welded. Attach the welding ground cable directly to the area to be welded. Protect all machined surfaces from sparks or splatter produced by the welding, chipping, and/or grinding operations. The welds shall be free from cracks, porosity, undercut, and incomplete fusion. All weld quality shall conform to ANSI/AWS D14.3.

NOTE: 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:

500 MPa (72 KSI) Tensile Strength

420 MPa (60 KSI) Yield Strength

22% elongation to 50 mm (2 in)

27 J (20 ft. lb) Notch Toughness at -29°C (-20°F)

These are low hydrogen electrodes and must be stored in an electrode oven at 121°C (250°F) when not in use. If the electrodes get damp, scrap or recondition them to the manufacturer's specifications. The following chart relates to the electrodes diameter and approximate current settings for welding: