Repair by welding–Permanent molds made of steel exhibit longer life because deteriorated areas may be repaired by conventional welding.
Restoration of deteriorated areas as well as other areas of the mold cavity subjected to thermal shock or liquid metal erosion may be done using special surfacing material Ni-base alloy electrodes. With this process, the repaired mold areas do not require subsequent heat treatment as the hardness of the welded area is in the 171185 HB range and easily can he machined to the desirable shape and size.
When iron is used as the mold material, repair by conventional welding is not effective. One method to extend iron mold life is the use of thermal spray welding. A powder Fe-Ni-based alloy can be used to fill fissures and points of wear on the iron mold surface, With this method, it is critical that the thermal expansion of the sprayed metal must be similar to that of the mold.
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