17-4PH Stainless Steel (UNS S17400): Precipitation-Hardening Strength and Applications

17-4PH (UNS S17400, AISI 630, 1.4542) is a martensitic precipitation-hardening stainless steel that delivers very high strength with good corrosion resistance. This guide covers composition, heat-treatment conditions (H900–H1150), mechanical properties, standards and applications.