15-5PH Stainless Steel is a Precipitation Hardening martensitic stainless steel, hardened by a single age H900-H1150°F temperature range. Corrosion resistant, excellent transverse toughness and ductility in large cross sections. UNS S15500 XM-12. VAR (CEVM) Consumable Electrode Vacuum Melted. ESR Electroslag Remelt.