Weld Mold 9770 description: Weld Mold 9770, 18% nickel, precipitation hardening (martensitic age hardening) alloy was developed for the repairing of hot work dies and tools. 9770 is composed of moly-nickel-cobalt alloys. Weld Mold 9770 is primarily used in the Die Casting Industry to increase the die life by plastic molds, extrusion dies, ejector pins, core rams and dummy blocks. Also effective repairing certain types of forging die inserts. Weld Mold 9770 can also be applied to S.A.E. alloy steels such as 4140-4340, to create working surfaces that have the same RC hardness and Maraging qualities as the original Maraging alloys.