Finkl 420MB is a resulfurized modification of AISI 420F stainless steel for mold bases. The alloy is clean, tough, and machinable. It is available by VAD and balanced oxidation techniques. This datasheet provides information on composition, physical properties, and hardness. It also includes information on heat treating. Filing Code: SS-703. Producer or source: A. Finkl & Sons Company.