17-4PH is a martensitic precipitation-hardening stainless steel, offering a balanced combination of high strength, good corrosion resistance, and machinability. Its core performance characteristics are as follows:
Mechanical Properties
After solution treatment + aging, the tensile strength reaches 1000–1400 MPa, and yield strength is 800–1200 MPa. Hardness ranges from 30–45 HRC, depending on aging parameters. Toughness is superior to ordinary martensitic stainless steels, maintaining good impact resistance even at low temperatures.
Corrosion Resistance
Resistant to atmospheric, freshwater, and neutral salt environments. Provides moderate resistance to organic acids and weak alkaline solutions. Corrosion resistance is slightly lower than 304 stainless steel but superior to 410, 420, and other conventional martensitic steels.
Machining and Heat Treatment
In solution-treated condition (1040–1060 °C with rapid cooling), it is easy to cut, punch, and machine. Aging treatment (480–620 °C) strengthens the steel, increasing hardness and tensile strength. Welding is feasible, but post-weld aging is recommended to restore full strength in the heat-affected zone.
Other Properties
Good toughness at room temperature and stable impact performance at low temperatures (down to -50 °C). Non-magnetic or weakly magnetic. Surface finish can be improved via polishing to achieve high gloss and smoothness.