Boehler M238 VMR is a hardened and tempered plastic mold steel with excellent cleanliness for best polishability, making it ideal for lens mold tooling. The hardness is consistent over the entire cross section of the steel block, even in large sizes, due to the addition of nickel. This datasheet provides information on composition, physical properties, hardness, and elasticity. It also includes information on heat treating and joining. Filing Code: TS-640. Producer or source: Böhler-Uddeholm North America.