One application for repair welding is to restore the integrity of a component where a crack has been found. Cracks can appear during in-service or already in the manufacturing process. The latter is usually the case for large castings where cracks may have formed. The repair welding in this entry is the process of filling a premachined slot. This slot has been milled in order to remove the crack that has been found. The welding process can be any kind of arc, beam, or gas welding process. However, manual arc welding is the most common method for repair welding. Thereafter, the component may need to be heat treated in order to reduce residual stresses and/or restore material microstructure. Local heat treatment means that only a part of the structure is heat treated. This is in contrast to global heat treatment where the entire structure is heat treated by placing it in a furnace. We focus on the use of induction heating for local heat treatment in the current entry.