How to deal with metal casting defects?
As a buyer or manufacturer for metal castings, the casting defects are always the problems you need to deal with, since the casting defects are inevitable even for the best manufacturer. Therefore, how should the manufacturers and buyers deal with the metal castings with defects?
1. In production and inspection
As for the metal foundries, we should try to avoid or reduce the casting defects, and we should try to repair them if we found the defects during production and inspection if the repairing is allowable.
The normal methods will be welding and using cast iron glue. We usually use electrical welding method to repair the large cracks, sand holes and air holes, and use the cast iron glue to mend small sand hole, air holes and shrinkage areas. Both welding and cast iron glue have very high hardness and strength, so they will not affect the application. However, the repairing should be applied for the rough surfaces, as for the machining surfaces, the repairing should be forbidden.
2. In the hand of clients
When clients receive the iron or steel castings, then they found the casting defects, this will be an awkward problem for both clients and manufacturers. Because, the repairing is easy for manufacturers, but very difficult for buyers since the clients do not have the repairing materials and equipments, and it is more difficult to return the metal castings back to the foundries. So, how should we deal with this situation?
We normally require the clients to send some photos of defects to us, then we will check if the defects are really our problems, and what kind of problems they were, and figure out how to solve the casting defects in the place of our clients.
However, as I said, usually the clients have no ability to repair the defects, so we will have to replace the castings with defects free of charge. We normally sent more castings to the clients in the next order as the free replaced castings.
As for the machining surfaces, of course, there is no good method to repair the casting defects since the repairing may affect the application