Usage:
5230 (7LL) Excavators
Description of Change: Plates have been added to the front and rear of the carbody. The new plates will help prevent cracking in the side plates of the carbody.
Adaptable To: Two new 146-8989 Plates (not serviced) and two new 150-9186 Plates (not serviced) are effective with 5230 (7LL81) Excavators. The plates are adaptable to all earlier machines using the following procedure.
Weld Information
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Protect yourself and others; read and understand this warning. Fumes and gases can be dangerous to your health. Ultraviolet rays from the weld arc can injure eyes and burn skin. Electric shock can kill.
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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 the 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 CRC 1910, available from U.S. Dept. of Labor, Washington, D.C.
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 fillet welding, as outlined in 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 all welding.
The SMAW process shall be used with E7018 (ANSI/AWS A5.5) 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 in 50 mm (2 in)
- 27 J (20 ft lb) Notch Toughness at -29°C (-20°F)
- 420 MPa (60 KSI) Yield Strength
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 manufacturers specifications.
The following chart relates to the electrode diameter and approximate current settings for welding:
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 E71T-1 (ANSI/A5.20) welding electrode and the manufacturers specified shielding gas (es). 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 in 50 mm (2 in)
- 27 J (20 ft lb) Notch Toughness at -18°C (0°F)
- 420 MPa (60 KSI) Yield Strength
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's slag system, there is a chance of trapping evolving gasses 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 (0.052 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 (0.31 in) bevel groove weld volume.
Clean the carbody of oil, grease, paint, and dirt in the area to be welded. Attach the welding ground cable directly to the area to be welded. Attach the welding ground cable directly to the carbody. 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.
Procedure To Reinforce The Carbody
Illustration 1.
Rear view of the carbody.
1. Inspect the corners at the side plates of the carbody for cracks in the areas shown in Illustration 1. Inspect two areas at the front of the machine and inspect two areas at the rear of the machine.
2. If any cracks are found, use an air carbon arc to gouge out the cracks, then fill with weld and grind smooth.
Illustration 2.
150-9186 Plate (not serviced).
Illustration 3.
146-8989 Plate (not serviced).
3. Fabricate two 146-8989 Plates (2) (not serviced) as shown in Illustration 2 and Chart 4. Fabricate two 150-9186 Plates (1) (not serviced) as shown in Illustration 3 and Chart 4. Fabricate four plates from 345 MPa (50,000 psi) minimum yield strength structural steel.
4. Weld one 146-8989 Plate (2) (not serviced) to the right rear of the carbody and one 146-8989 Plate (2) (not serviced) to the left front of the carbody as shown in Illustration 1 and Chart 3.
5. Weld one 150-9186 Plate (1) (not serviced) to the left rear of the carbody and one 150-9186 Plate (1) (not serviced) to the right front of the carbody as shown in Illustration 1 and Chart 3.