17-7PH Stainless Steel
17-7PH is an austenitic martensitic precipitation hardening stainless steel developed from 18-8CrNi with an aluminum addition. It contains 16% to 18% chromium, 6.5% to 7.75% nickel, and 0.75% to 1.5% aluminum. Solution treatment produces an unstable austenitic structure that transforms during aging into low carbon tempered martensite. The source lists high strength, hardness of HRC 38 to 46, corrosion resistance above ordinary martensitic stainless steel, and fatigue resistance. Heat treatment can adjust properties for service at ≤427℃.
Product details
Chemical composition
| 17-7PH | C | Si | Mn | P | S | Ni | Cr | Al |
|---|---|---|---|---|---|---|---|---|
| min | – | – | – | – | – | 6.5 | 16.0 | 0.75 |
| max | 0.09 | 1.0 | 1.0 | 0.04 | 0.03 | 7.7 | 18.0 | 1.5 |
Grade equivalents
| English Item | UNS | W.Nr. | JIS | GB/T | Other Grades |
|---|---|---|---|---|---|
| 631 17-7PH | S17700 | 1.4568 | SUS631 | 07Cr17Ni7Al 0Cr17Ni7Al | X7CrNiAl17-7 |
Physical properties
| Density g/cm³ | 7.85 |
|---|---|
| Melting range ℃ | 1390-1430 |
| Thermal conductivity (100℃) λ/(W/m•℃) | 16.3 |
| Specific heat J/kg•℃ | 460.6 |
| Elastic modulus GPa | 200 |
| Electrical resistivity μΩ•m | 0.8 |
| Linear expansion coefficient a/10-6℃-1 | 15.3 |
Mechanical properties
| Tensile strength Rm N/mm | ≥1140 |
|---|---|
| Yield strength RP0.2 N/mm | ≥960 |
| Elongation % | ≥5 |
| Hardness HB | ≥363 |
| *After aging heat treatment | |
Available product forms
- Round Bar
- Plate
- Pipe & Tube
- Welding Consumables
- Flanges
- Hex Bolts
- Threaded Rod
- Nuts & Washers
Technical values are transcribed and translated from the supplied Milike Chinese catalogue. Confirm the applicable purchase specification, heat treatment condition, and inspection requirements before final material selection.
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