Weld Mold 959 description: Weld Mold 959 produces hot working weld deposits that are tungsten-free, homogeneous, porous-free, dense, and may be annealed and rehardened, if necessary. Matches A.I.S.I. H-13 tool steel heat treatment. Primarily designed for use on tools and dies subject to heat checking and wear. Examples include: die casting dies used in the aluminum, magnesium, and zinc die casting industries as well as for repair of press forging dies and inserts. May be used on other hot or cold working units such as shears, punches, trim sections, etc.