17-4PH Stainless Steel

17-4PH stainless steel (also known as 630 stainless steel) is a precipitation-hardening martensitic alloy that combines high strength, hardness, and good corrosion resistance. It achieves its mechanical properties through heat treatment, allowing a wide range of strength levels while maintaining dimensional stability. Common heat-treat conditions include H900, H1025 and H1150, each trading peak strength for improved ductility and toughness — H900 delivers the highest strength, while H1150 favors toughness for more demanding structural applications. This grade is widely used in aerospace components, chemical processing equipment, pump shafts, valves, fasteners, and offshore applications. It performs well in mildly corrosive environments and offers excellent fatigue strength and wear resistance, making it suitable for critical structural parts. It is supplied in round bar form under standards such as ASTM A564/A564M. 17-4PH (UNS S17400, also known as 630 stainless steel) is the standard precipitation-hardening grade for aerospace fasteners and high-strength structural parts where heat-treatable strength and corrosion resistance both matter.