ROD,PISTN AS 0933485 - Caterpillar

Rework Procedure
Place the machine in a suitable position for carrying out the rework.
Perform welding in 4G Overhead and 4F Overhead positions.
It is important that the welder who is carrying out the rework must be qualified in the above mentioned positions as outlined in the current ANSI/AWS standards.
Clean the cracked/damaged weld area to ensure that it is free from oil, paints, grease, rust.
Keep the plate surfaces and welding rods dry to prevent the welds from cracking.
Use a pencil type grinder in order to clean the welds. A disc type grinder should not be used.
Conduct a Dye Penetrant (DP) to ascertain the extent of the weld defect and precisely to find out the edges of the crack.Note: All slag or foreign material must be removed from the crack before checking with Dye Penetrant.
Remove the cracked region by grinding. Check the area with DP to ensure that the crack should be removed.
Ensure that slag and other by products from the removal process do not cover up the defective weld before checking with DP.
Ensure that the entire defective weld has been removed down to solid material by using DP.
Extend the weld metal removal beyond the defect/crack - minimum 25 - 50 mm both ends.
Keep the rework surface free from moisture and dust.
Remove the defects to sound metal prior to welding. Taper the ends of the reworking area to provide a smooth transition to the base metal.
Follow the procedure below to carry out the rework.
Illustration 4 g03827964
Upper frame assembly top view
Illustration 5 g03827972
Upper frame assembly bottom view (1) Area 01 & 02 upper frame assembly RHS & LHS Front (2) Area 03 & 04 upper frame assembly RHS & LHS Rear
Illustration 6 g03827976
(3) Welding not permitted within 10 mm for the edges
Illustration 7 g03828050
Existing weld
Illustration 8 g03828052
Edge preparation requirement depends on crack location
Illustration 9 g03828058
Proposed weld
Clean the cracked or damaged area to ensure its free from oil, paints, grease, rust
Make sure all the electrical cables, oil hoses are removed or protected from welding heat.
Remove the existing cracked weld by using a pencil grinder.
Make a bevel groove preparation on the failed location as shown above. Extreme care should be taken while creating the bevel groove since excess base material removal will deteriorate the structure and make sure that the bevel groove depth should be restricted to 4 - 5 mm max.
Use a pencil grinder for the bevel groove preparation.
Fill the groove with weld metal and make a fillet weld as per the drawing requirement.
The final capping weld must not exceed 2 mm (0.08 inch) with good wetting profiles on the toes of the weld.
Use a suitable grinding/finishing equipment to smooth the surface of the built up area to the original profile (matching with the adjacent area).
Make sure that the weld start / stop should be eliminated at corner location. The weld start / stop needs to be merged smoothly and it should be free from weld defects like crater and lack of sidewall fusion.
Check for visual weld defect inspection. If anything any defects are noticed, grind the defective location and