Stainless 17-4PH · UNS S17400 · W. Nr. 1.4542
Stainless 17-4PH (S17400): composition, properties, fittings and flanges
Stainless 17-4PH (S17400, W. Nr. 1.4542) is Martensitic precipitation-hardening stainless steel. Stainless 17-4PH is specified at Chromium 15.00 - 17.50, Nickel 3.00 - 5.00, Copper 3.00 - 5.00. 17-4PH is the workhorse PH stainless: a single low-temperature age at 480 °C (H900) takes it to 1310 MPa tensile while keeping…
- UNS
- S17400
- W. Nr.
- 1.4542
- Density
- 7.80 g/cm³ (0.282 lb/in³)
- Key strength
- 1310 MPa / 190 ksi
Identification and standards
| Short form | Stainless 17-4PH · UNS S17400 · W. Nr. 1.4542 |
|---|---|
| Classification | Martensitic precipitation-hardening stainless steel |
| UNS | S17400 |
| Werkstoff number | 1.4542 |
| Material family | Stainless Steel |
Chemical composition
| Element | Composition (wt %) | Why it is there |
|---|---|---|
| Chromium (Cr) | 15.00 - 17.50 | Corrosion resistance |
| Nickel (Ni) | 3.00 - 5.00 | Austenite retention and toughness |
| Copper (Cu) | 3.00 - 5.00 | Precipitation hardening |
| Niobium + Tantalum | 0.15 - 0.45 | Carbide and precipitate control |
| Carbon (C) | 0.07 max | - |
| Manganese (Mn) | 1.00 max | - |
| Silicon (Si) | 1.00 max | - |
| Iron (Fe) | Balance | Matrix |
Note Single figures are maximum limits unless shown as a range. Always confirm against the heat-specific EN 10204 3.1 certificate supplied with your order.
Mechanical properties
| Tensile strength, min (H900) | 1310 MPa / 190 ksi |
|---|---|
| 0.2 % yield strength, min (H900) | 1170 MPa / 170 ksi |
| Elongation in 2 in, min (H900) | 10 % |
| Typical hardness, H900 | 38 - 44 HRC |
| Maximum useful service temperature | About 300 °C for full strength |
Warning Values depend on product form, section thickness and heat treatment. Larger sections generally achieve lower strength than thin product; always design against the applicable code allowable stress rather than these figures.
Physical properties
| Density | 7.80 g/cm³ (0.282 lb/in³) |
|---|---|
| Melting range | 1400 - 1440 °C (2550 - 2625 °F) |
| Modulus of elasticity | 196 GPa (28.4 x 10⁶ psi) |
| Thermal conductivity at 20 °C | 17.9 W/m·K |
| Mean coefficient of thermal expansion, 20-100 °C | 10.8 µm/m·°C |
| Specific heat capacity | 460 J/kg·K |
Specifications by product form
| Forgings & flanges | ASTM A564 / A705 Type 630 (UNS S17400) |
|---|---|
| Butt weld fittings | ASTM A403 / A815 family or to order |
| Seamless pipe & tube | To order against ASTM A564 chemistry |
| Plate / sheet / strip | ASTM A693 Type 630 |
| Bar / rod | ASTM A564 / A705 · NACE MR0175 in H1150 condition |
| Welding consumables | ER630 or ERNiCr-3 |
| UNS / EN / China | UNS S17400 · W. Nr. 1.4542 · GB 05Cr17Ni4Cu4Nb |
Product forms available
Hangbo supplies this grade in the following forms. Sizes outside the listed range can often be produced to order.
- Forged flanges blanks and finished flanges to ASME B16.5, B16.47 Series A/B and B16.36
- Butt weld elbows, tees, reducers, caps and stub ends to ASME B16.9 and MSS SP-43
- Seamless pipe and tube to the applicable ASTM / ASME pipe specification
- Forged rings, discs and hubs machined to your drawing
Typical applications
- Valve stems, shafts, gears and pump components
- Aerospace structural fittings and fasteners
- Oil and gas tool components in H1150 sour condition
- Nuclear, marine and food machinery parts
Welding, forming and machining
- Welding
- Weld in the solution-annealed or over-aged condition with ER630 filler, then apply the ageing treatment to the whole assembly so that the heat affected zone and parent metal harden together.
- Heat treatment
- Solution anneal at 1040 °C, then age: H900 at 480 °C, H1025 at 550 °C, H1150 at 620 °C. Higher ageing temperatures trade strength for toughness and sour service compliance.
- Hot and cold forming
- Hot work in the range stated by the mill for this grade, then re-solution or re-age before final machining so that the delivered condition matches the certificate.
- Machining
- Machine with sharp carbide or high-speed steel tooling, positive rake, constant feed and ample coolant. Never dwell - the surface work-hardens quickly.
Buy Stainless 17-4PH from Hangbo
Material is supplied with full heat-number traceability, solution annealing or ageing performed under calibrated furnace control, and an EN 10204 3.1 certificate covering chemical analysis, mechanical properties, heat treatment records and the agreed NDT scope. Positive material identification and third party inspection and test reports from SGS are available for critical service.