Stainless 15-5PH · UNS S15500 · W. Nr. 1.4545
Stainless 15-5PH (S15500): composition, properties, fittings and flanges
Stainless 15-5PH (S15500, W. Nr. 1.4545) is Martensitic precipitation-hardening stainless steel. Stainless 15-5PH is specified at Chromium 14.00 - 15.50, Nickel 3.50 - 5.50, Copper 2.50 - 4.50. 15-5PH is the cleaner, vacuum-remelted evolution of 17-4PH: lower delta ferrite gives better transverse toughness and more uniform…
- UNS
- S15500
- W. Nr.
- 1.4545
- Density
- 7.80 g/cm³ (0.282 lb/in³)
- Key strength
- 1310 MPa / 190 ksi
Identification and standards
| Short form | Stainless 15-5PH · UNS S15500 · W. Nr. 1.4545 |
|---|---|
| Classification | Martensitic precipitation-hardening stainless steel |
| UNS | S15500 |
| Werkstoff number | 1.4545 |
| Material family | Stainless Steel |
Chemical composition
| Element | Composition (wt %) | Why it is there |
|---|---|---|
| Chromium (Cr) | 14.00 - 15.50 | Corrosion resistance |
| Nickel (Ni) | 3.50 - 5.50 | Toughness and austenite retention |
| Copper (Cu) | 2.50 - 4.50 | Precipitation hardening |
| Niobium + Tantalum | 0.15 - 0.45 | 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 |
| Transverse toughness vs 17-4PH | Markedly better |
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 XM-12 (UNS S15500) |
|---|---|
| Butt weld fittings | To order against ASTM A564 chemistry |
| Seamless pipe & tube | To order |
| Plate / sheet / strip | ASTM A693 Type XM-12 |
| Bar / rod | ASTM A564 / A705 |
| Welding consumables | ER630 or matching 15-5PH filler |
| UNS / EN / China | UNS S15500 · W. Nr. 1.4545 |
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
- Aerospace structural parts and landing gear components
- High-strength shafts, gears and fasteners
- Nuclear and defence hardware needing through-thickness toughness
- Valve and pump components in heavy sections
Welding, forming and machining
- Welding
- Weld with matching or ER630 filler in the solution-treated condition, then age the assembly. Uniform response through the section is the reason to specify 15-5PH over 17-4PH.
- Heat treatment
- Solution anneal at 1040 °C, then age at 480 - 620 °C depending on the specified condition from H900 to H1150.
- 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 15-5PH 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.