PROBLEM:

Illustration 1.

Illustration 2.

Illustration 3.

SOLUTION:

Engine Preparation

1. Turn off the engine. Place the engine start switch in the OFF position.
2. If equipped, turn the battery disconnect switch to the OFF position. If there is no battery disconnect switch, disconnect the negative battery cable at the battery or negative 24V power supply.

Note: This is the position of the machine Service or storage.

3. Connect the welding ground cable directly to the actual base to be welded. Clean the area where the clamp is applied to ensure a good current path. Clamp the cable as close as possible to the weld in order to reduce the possibility of current damage to the drive train bearings, generator bearings, electrical components (such as ground straps), and other engine/generator components.

_________________________NOTICE_________________________________

Do not use electrical components (ECM?s or ECM sensors) or electronic component grounding points for grounding the welder.

________________________________________________________________

 

4. Protect any harnesses from welding debris or splatter.
5. Use the following welding procedure to weld materials together.

PROCEDURE

Step 1: Prepare for Welding

1. Remove the crack, creating a groove weld joint geometry. (Remove material 25.4 mm (1 inch) beyond the end of the visible sign of crack). This may be accomplished using an arc gouge or by grinding.
2. Shape the weld joint such that the welder will have good access to the root and can produce a continuous full penetration weld.
3. Clean the grooves by removing all residual carbon, grease, oil, etc. If arc gouging is used, take care to remove all of the residual base metal. The melted base metal has a tendency to adhere to the un-melted base metal and is difficult to remove by grinding. A pneumatic chipper will remove this material.
4. Remove 12.7 mm (.50 inch) of the outer edge of the gusset (point) by grinding. This will result in a vertical surface.
5. Remove the paint, by grinding, on the top surface of the plate at least 50.8 mm (2 inches) from the weld joint.
6. Visually inspect to make sure the entire crack is removed.
7. Use an NDT process, such as a dry mag with a yoke, to verify that the entire crack is removed.

Step 2: Weld Repair

1. Weld the joint with a low hydrogen process and a matched electrode. See Table 1.
2. The fillet welds along the sides of the angled gusset should extend 12.7 mm (.50 inch) beyond the end of the gusset.

Note: The end of the gusset must remain open and not welded.

Note: As a rule of thumb, the "more overwelded" the fillet (any) weld, the poorer the geometry; the higher the stress concentration, the shorter the fatigue life.

3. Clean the weld surface between each pass.
4. Visually inspect each pass for surface defects.
5. See Illustrations 4 and 5 for weld details and to ensure that the final weld is within the fillet size requirements of these drawings, (i.e., Do not add multiple passes making the fillet size larger than plan.).

PRODUCTION WELDS FOR ENGINE AND GENERATOR MOUNTS

Step 3: Post Weld Inspection

Step 4: Post Welding Processing

1. Grind the surfaces of the weld smooth with the top surface of the base metal.
2. Maintain the original contour of the base material.
3. Use a NDT process, such as a dry mag with a yoke, to verify that there are no cracks in the weld.

Step 5: Establish a Periodic Inspection Plan for Repaired Region

INSTALLATIONS WITH CRACKED BASES