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Weld Mold® 9770

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.

Maraging 250 alloy chemistry conforms to AMS 6501.


Make sure the die to be repaired is very clean, free of any dirt or foreign substance. Also any cracks or heat checks must be removed. Preheat is dictated by the base material. When welding on Maraging steel it is important to minimize overall heat input. Keep the material as cool as possible, preheat is not recommended. Temper material after welding. It is not uncommon for the weldment to develop a small amount of crust on the surface. Remove this with a clean stiff stainless steel wire brush or grind it lightly. When TIG welding avoid using a torch that has been used to weld any copper based or aluminum alloys.

GMAW - DC+ (short circuit) 92% Ar 8% CO2 or (spray) 90% He 7.5% Ar 2.5% CO2 DC-
GTAW - DC- 100%Ar

Technical Data

Maraging or Tempering (Grade 250) at:

*Note: If 9771 (Grade 300) is used the hardness will increase about 3 RC points



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