17-4 PH Stainless Steel (UNS S17400): Precipitation Hardening
ASTM A564/A693 · Updated: 2026-05-25
17-4 PH (UNS S17400) is a martensitic precipitation-hardening stainless steel containing 15-17.5% Cr, 3-5% Ni, and 3-5% Cu. It achieves ultra-high strength (up to H900 condition: 1,170 MPa yield) through precipitation of copper-rich phases during a simple single-step aging treatment at 480-620°C—far simpler than the quench-and-temper cycle of conventional martensitic steels. Excellent combination of high strength, good corrosion resistance (comparable to 304), and dimensional stability during heat treatment. Widely used for aerospace structural components, pump shafts, valve stems, gears, and nuclear waste containers.
Quick Facts
| Category | Stainless Steel |
| Standard | ASTM A564/A693 |
| Density | 7.80 g/cm³ |
| Yield Strength | 1,000-1,170 MPa (145-170 ksi) H900 |
| Tensile Strength | 1,070-1,310 MPa (155-190 ksi) H900 |
Global Equivalents & Cross-Reference
| Alternative Standard / Grade | Action |
|---|---|
| EN 1.4542 | Compare |
| X5CrNiCuNb16-4 | Compare |
| SUS630 | Compare |
| 05Cr17Ni4Cu4Nb | Compare |
| 17-4PH | Compare |
Related Materials
🧮 Material Weight Calculator
Calculate the weight based on this material's density: 7.80 g/cm³
Frequently Asked Questions
What is the difference between H900 and H1150 aging conditions?
H900 (aged at 480°C/900°F for 1 hour) achieves maximum strength (~1,170 MPa YS) but with reduced toughness and some susceptibility to stress corrosion cracking. H1150 (aged at 620°C/1150°F for 4 hours) trades ~25% strength for dramatically improved toughness, ductility, and SCC resistance. H1150 is preferred for oil & gas, marine, and nuclear applications. H900 is used for aerospace components where maximum strength-to-weight ratio is critical.