Stainless Steel
Stainless Steel 17-4PH
Precipitation-hardening martensitic. UTS ~1100 MPa with corrosion resistance.
17-4PH is a precipitation-hardening martensitic stainless steel combining high strength (up to 1310 MPa post-aging) with moderate corrosion resistance. Cu-bearing variant of 410-class martensitic SS. Magnetic. Standard for aerospace shafts, fasteners, valve stems.
Equivalent Designations
| Standard | Designation |
|---|---|
| UNS | S17400 |
| Werkstoff Nr. | 1.4542 |
| AFNOR | Z6CNU17-04 |
| JIS | SUS 630 |
| EN | X5CrNiCuNb16-4 |
Standards
ASTM / ASME SA 582, A276, A564ASTM A484 (general requirements for bars)
Chemical Composition (% by mass)
| C | 0.07 max |
| Cb + Ta | 0.45 max (5×C min) |
| Cr | 15.0–17.5 |
| Cu | 3.0–4.0 |
| Fe | Balance |
| Mn | 1.0 max |
| Mo | 0.05 max |
| Ni | 3.0–5.0 |
| P | 0.07 max |
| S | 0.03 max |
| Si | 1.0 max |
Mechanical Properties
| Ultimate Tensile Strength (H1025) | 1100 MPa (160 000 psi) |
| Yield Strength (H1025) | 1000 MPa (145 000 psi) |
| Elongation | 5 % |
| Rockwell Hardness | C35 HRC |
Physical Properties
| Density | 7.75 g/cm³ |
| Melting Point | 1404–1440 °C |
Available Forms & Sizes
| Form | Size Range | Notes |
|---|---|---|
| Round Bar | Ø4 mm to Ø500 mm | — |
| Bright Bar | Ø4 mm to Ø100 mm | — |
| Hex Bar | 18 mm to 57 mm A/F | — |
| Flat Bar | 1/2″ to 10″ wide × 2 mm to 150 mm thick | — |
Use Cases
Aerospace structural fittings, shafts, fasteners
High strength + moderate corrosion resistance + magnetic.
Pump shafts, valve stems, mechanical seals
In oil & gas, chemical service.
Firearm components
Slides, barrels (shorter wear life than chrome-moly but corrosion resistant).
Process precision components
Gears, machine spindles where corrosion + hardness both required.
Design Notes
- Heat-treatment conditions (always specify on order): H900 (44 HRC), H925 (42 HRC), H1025 (35 HRC), H1075 (32 HRC), H1100 (31 HRC), H1150 (28 HRC).
- Always order in solution-annealed condition (Condition A: 1040 °C, AC, 32 HRC) unless specifying a heat-treat condition. Your shop performs precipitation aging.
- Welding: TIG with AWS A5.9 ER630 filler. Re-solution + age after welding for full strength.