COVER A 0398426 - Caterpillar

Illustration 1 g02047115
(A) Progression of the crack from the bottom to the top (B) Starting point of the crack
Illustration 2 g02047174
(C) Lack of weld penetration In some cases, a welder may not be familiar with the profile of the base edge that is under the abrasion adapter. This can result in not obtaining a good penetrating weld under the adapter noses into the base edge. The welder that is working on this procedure should be aware that the base edge under the adapter nose should always be ground to a 25 ° bevel. The early designs of the base edge specified a J-Groove weld. This weld was to the underneath side of the adapter nose. However, limited access to the welding angle of the groove often resulted in poor fusion into the base edge. High loads on the adapter would result in the initiation of a crack at the edge of the weld. This crack would spread up the bevel at the base edge through the adapter strap. This example is shown in illustration 1. The fracture face would reveal a weld with a nearly flat surface with little penetration into the base edge. This example is shown in illustration 2.Note: If a similar failure occurs with a flush mounted adapter add a 25 ° bevel to the base edge before welding. Replacement Procedure
Illustration 3 g02057374
(D) 25° bevel into the blunt height All current systems for adapters have a 25 ° bevel that is cut into the blunt height at the point of attachment. Every adapter is attached to this area. Use the following instructions when you replace a broken adapter:
Grind a 25° bevel into the blunt height of the base edge.
Make sure that the groove is equal to the width of the adapter.
Blend the groove into the vertical portion of the base edge.
Make the bevel as high as the J-Groove on the adapter.
The V-Groove should permit good penetration and fusion of the weld into both the base edge and the adapter.