17-4PH Stainless Steel
17-4PH is a martensitic precipitation hardening stainless steel containing 15.0% to 17.5% chromium, 3.0% to 5.0% nickel, 3.0% to 5.0% copper, and 0.15% to 0.45% niobium. Martensitic transformation and aging form the hardening precipitates, producing high strength and hardness up to 40HRC. The source describes corrosion resistance close to 304 stainless steel, adjustable properties through heat treatment, stable mechanical performance below 300℃, good weldability, and resistance to corrosion fatigue.
Product details
Chemical composition
| 17-4PH | C | Si | Mn | P | S | Ni | Cr | Cu | Nb |
|---|---|---|---|---|---|---|---|---|---|
| min | – | – | – | – | – | 3.0 | 15.0 | 3.0 | 0.15 |
| max | 0.07 | 1.0 | 1.0 | 0.04 | 0.03 | 5.0 | 17.0 | 5.0 | 0.45 |
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Grade equivalents
| English Item | UNS | W.Nr. | JIS | GB/T | Other Grades |
|---|---|---|---|---|---|
| 17-4PH | S17400 | 1.4542 | SUS630 | S51740 05Cr17Ni4Cu4Nb 0Cr17Ni4Cu4Nb | X5CrNiCuNb16-4 X5CrNiCuNb17-4 Z6CNU17-04 STS630 |
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Physical properties
| Density g/cm³ | 7.78 |
|---|---|
| Melting range ℃ | 1350-1420 |
| Thermal conductivity (100℃) λ/(W/m•℃) | 18.3 |
| Specific heat J/kg•℃ | 502 |
| Elastic modulus GPa | 196 |
| Electrical resistivity μΩ•m | 0.98 |
| Linear expansion coefficient a/10-6℃-1 | 10.8 |
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Mechanical properties
| Tensile strength Rm N/mm | ≥1310 |
|---|---|
| Yield strength RP0.2 N/mm | ≥1180 |
| Elongation % | ≥10 |
| Hardness HB | ≥375 |
| *After aging heat treatment | |
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Applications
- Offshore platforms and ships: helicopter decks and corrosion-resistant structural parts such as bolts and shafts
- Food processing: components with high hygiene requirements, including valves and piping
- Pulp and paper: pump and agitator components handling corrosive pulp
- Aerospace: turbine blades and engine structures for service at or below 300℃
- Petrochemical processing: reactors, heat exchangers, and piping handling sulfur-bearing or chloride media
- Nuclear power: nuclear-waste storage vessels and radiation- and corrosion-resistant structures
- Medical equipment: high-strength corrosion-resistant surgical instruments and implants such as orthopaedic screws
Available product forms
- Round Bar
- Wire
- Forgings
- Plate
- Strip
- Seamless Pipe
- Welded Pipe
- Capillary Tube
- Flanges
- Pipe Fittings
- Non-standard Custom Parts
Values follow the Milike materials catalogue and are provided for preliminary review. Confirm the applicable purchase specification, heat treatment condition, and inspection requirements before final material selection.
- Heat and batch traceability
- PMI testing available
- Cut-to-size processing
- Material certificates on request
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