PH 13-8 Mo Stainless Steel (UNS S13800) is a martensitic precipitation-hardening stainless steel that has excellent strength, high hardness, superior toughness, and good corrosion resistance. Good transverse toughness properties are achieved by tight chemical composition control, low carbon content, and vacuum melting. The alloy is produced by vacuum induction melting (VIM) followed by electro-slag remelting (ESR). This melt practice promotes excellent macro- and microcleanliness, and tight compositional control. The strengthening mechanism (precipitation hardening in a martensitic matrix) makes it possible to achieve uniform strengthening in heavy sections. Strength and ductility levels can be tailored to the application by varying the aging temperature.