17-4PH Stainless (UNS S17400)
Martensitic precipitation-hardening stainless steel — high strength and corrosion resistance from a single low-distortion age.
- UNS
- S17400
- W.Nr / EN
- 1.4542
- Density
- 7.75 g/cm³
- Service range
- To ~315 °C (age-stable)
About 17-4PH Stainless
17-4PH is the most widely used precipitation-hardening stainless steel. A copper-bearing martensitic matrix is hardened by a single low-temperature ageing treatment, so parts reach up to ~1310 MPa tensile strength with minimal distortion — often machined complete before hardening.
Corrosion resistance approaches that of 304 stainless in most environments, an unusual pairing with such strength levels. DMK Alloys supplies 17-4PH bars, forged blanks and finished components in the full range of H-condition heat treatments.
17-4PH Stainless chemical composition (weight %)
| Element | Limit / range |
|---|---|
| Fe | Balance |
| Cr | 15.0 – 17.5 |
| Ni | 3.0 – 5.0 |
| Cu | 3.0 – 5.0 |
| Nb (+Ta) | 0.15 – 0.45 |
| C | ≤ 0.07 |
| Mn | ≤ 1.0 |
| Si | ≤ 1.0 |
| P | ≤ 0.04 |
| S | ≤ 0.03 |
Composition limits per the commonly referenced standards listed below. Order-specific limits may differ — confirm against the governing specification.
17-4PH Stainless mechanical properties (typical)
| Condition / form | Tensile, MPa | 0.2% Yield, MPa | Elongation, % |
|---|---|---|---|
| Bar, condition H900, room temp. | ≥ 1310 | ≥ 1170 | ≥ 10 |
| Bar, condition H1025, room temp. | ≥ 1070 | ≥ 1000 | ≥ 12 |
| Bar, condition H1150, room temp. | ≥ 930 | ≥ 725 | ≥ 16 |
Values are typical or specification-minimum levels for guidance only — not a guarantee of properties. Certified values are established by testing against the ordered specification.
17-4PH Stainless specifications & international equivalents
| System | Designation | Covers |
|---|---|---|
| UNS | S17400 | All product forms |
| AMS | AMS 5643 | Bars, forgings, rings |
| AMS | AMS 5604 | Sheet, strip, plate |
| ASTM | ASTM A564 Type 630 | Bars, shapes |
| ASTM | ASTM A693 Type 630 | Plate, sheet, strip |
| W.Nr / EN | 1.4542 · X5CrNiCuNb16-4 | European cross-reference |
Cross-references are for guidance; the governing document is always the specification cited on your purchase order or drawing.
17-4PH Stainless physical properties
| Property | Typical value |
|---|---|
| Density | 7.75 g/cm³ |
| Melting range | 1400 – 1440 °C |
| Modulus of elasticity (family-typical) | ≈ 190 – 210 GPa |
| Indicative service range | To ~315 °C (age-stable) |
Forms we manufacture
- Bars
- Forged blanks
- Rings
- Machined components to drawing
Dimensional ranges and delivery conditions are confirmed per enquiry.
Where 17-4PH Stainless earns its keep
Typically specified for:
- Pump shafts
- Valve internals
- Actuator components
- Gears
- And structural fittings requiring stainless strength
Also consider
15-5PH Stainless
UNS S15500 · W.Nr 1.4545AMS 5659 · ASTM A564 XM-12
The ferrite-free refinement of 17-4PH: better transverse toughness for critical forged and premium-melted parts.
440C Stainless
UNS S44004 · W.Nr 1.4125AMS 5630 · AMS 5618
The hardest standard stainless steel: bearing-grade wear resistance at up to ~60 HRC with corrosion protection.
321 Stainless
UNS S32100 · W.Nr 1.4541AMS 5510 · AMS 5645
Titanium-stabilised austenitic stainless for welded assemblies in the 425–815 °C sensitisation range.
Request 17-4PH Stainless to your specification
State the governing standard, form, dimensions, quantity and testing requirements — the export team responds with a manufacturer's quotation.