Stainless Steel 17-4 PH
A precipitation-hardened martensitic stainless steel combining high strength (up to 1,300 MPa) with moderate corrosion resistance. 17-4 PH is used where hardness and wear resistance are needed alongside stainless properties.
About Stainless Steel 17-4 PH
17-4 PH (UNS S17400) is a chromium-nickel-copper stainless steel that can be hardened to various strength levels through heat treatment (aging). The H900 condition delivers the highest strength (~1,300 MPa) while H1150 provides better toughness and ductility at lower strength.
In AM, 17-4 PH presents some microstructural challenges — LPBF-produced parts can contain retained austenite alongside the desired martensite, requiring careful heat treatment to achieve target properties. Solution treating at ~1,040 °C followed by aging is typically required.
The material bridges the gap between austenitic stainless steels (like 316L) and tool steels — offering higher strength than 316L while maintaining reasonable corrosion resistance.
Typical Applications
- Aerospace fittings and fasteners
- Valve and pump components
- Gears and shafts
- Food processing machinery
- Medical instruments
Engineering Considerations
- Retained austenite in as-built LPBF parts — solution + aging heat treatment essential
- H900 condition is strongest but most brittle; H1150 offers better toughness
- Corrosion resistance is lower than 316L in chloride environments