17-4PH vs 15-5PH
These two grades are listed as equivalents of each other: their chemistry windows overlap and they serve the same applications. They are not always identical — check the differences below before substituting, especially in certified designs.
17-4PH
Stainless Steel
17-4PH (type 630) is the most widely used precipitation-hardening stainless steel, combining near-316 corrosion resistance with strength levels up to about 1300 MPa after a simple low-temperature age. It hardens with minimal distortion, so parts are machined soft and aged to final strength.
Standards: DIN 1.4542 · AISI 630 (17-4PH) · JIS SUS630 · GB 05Cr17Ni4Cu4Nb
15-5PH
Stainless Steel
15-5PH is a refinement of 17-4PH with tighter control of delta ferrite, giving better transverse toughness and ductility, especially in vacuum-melted quality. It is specified for aerospace and nuclear parts in heavier sections.
Standards: DIN 1.4545 (close) · AISI XM-12 (15-5PH) · GB 05Cr15Ni5Cu4Nb
Chemical composition compared (%)
| Element | 17-4PH | 15-5PH |
|---|---|---|
| C | ≤0.07 | ≤0.07 |
| Si | ≤1.00 | ≤1.00 |
| Mn | ≤1.00 | ≤1.00 |
| P | ≤0.040 | ≤0.030 |
| S | ≤0.030 | ≤0.015 |
| Cr | 15.00–17.50 | 14.00–15.50 |
| Ni | 3.00–5.00 | 3.50–5.50 |
| Cu | 3.00–5.00 | 2.50–4.50 |
| Nb | 0.15–0.45 | 0.15–0.45 |
Properties compared
| Property | 17-4PH | 15-5PH |
|---|---|---|
| Delivery condition | Solution treated (Condition A) or aged | Solution treated (Condition A) or aged |
| Hardness (H900 aged) | ~40 HRC | ~40 HRC |
| Tensile strength (H900) | ~1310 MPa | ~1310 MPa |
| Yield strength (H900) | ~1170 MPa | — |
| Density | 7.80 g/cm³ | 7.80 g/cm³ |
| Magnetic | Yes | Yes |
Sourcing either grade?
Nasteel stocks both families from Shenzhen with EN 10204 3.1 mill certificates by heat number.
Ask for a quotationSee full data sheets: 17-4PH · 15-5PH. Substitution decisions for certified parts stay with the design authority.