17-4PH (SS 630) vs SS 316L difference in composition & properties.
17-4PH (SS 630) is precipitation-hardening stainless; SS 316L is austenitic stainless. SS 316L contains molybdenum (2–3%); 17-4PH (SS 630) has no minimum for it.
Key differences between 17-4PH (SS 630) and SS 316L
- 17-4PH (SS 630) is precipitation-hardening stainless; SS 316L is austenitic stainless.
- SS 316L contains molybdenum (2–3%); 17-4PH (SS 630) has no minimum for it.
- Nickel: SS 316L 10–14% against 17-4PH (SS 630) 3–5%.
- Carbon: 17-4PH (SS 630) ≤0.07% against SS 316L ≤0.03%.
- 17-4PH (SS 630) contains copper (3–5%); SS 316L has no minimum for it.
- Density: 17-4PH (SS 630) 7.78 g/cm³, SS 316L 7.98 g/cm³.
17-4PH (SS 630) vs SS 316L chemical composition (weight %)
| Element | 17-4PH (SS 630) | SS 316L |
|---|---|---|
| C | ≤0.07 | ≤0.03 |
| Si | ≤1 | ≤0.75 |
| Mn | ≤1 | ≤2 |
| P | ≤0.04 | ≤0.045 |
| S | ≤0.03 | ≤0.03 |
| Cr | 15–17.5 | 16–18 |
| Ni | 3–5 | 10–14 |
| Cu | 3–5 | – |
| Nb+Ta | 0.15–0.45 | – |
| Mo | – | 2–3 |
| N | – | ≤0.1 |
Mechanical properties, equivalents and uses
| Property | 17-4PH (SS 630) | SS 316L |
|---|---|---|
| Family | Precipitation-hardening stainless | Austenitic stainless |
| Tensile strength, MPa | – | ≥485 |
| Yield strength, MPa | – | ≥170 |
| Elongation, % | – | ≥40 |
| Hardness | ≤363 HB | ≤217 HB |
| Density, g/cm³ | 7.78 | 7.98 |
| UNS | S17400 | S31603 |
| EN | X5CrNiCuNb16-4 | X2CrNiMo17-12-2 |
| W.Nr | 1.4542 | 1.4404 |
| JIS | SUS630 | SUS316L |
| IS (India) | – | X02Cr17Ni12Mo2 (IS 6911) |
| AISI / ASTM | ASTM A564 Type 630 | AISI 316L |
| Typical uses | Shafts, valve stems, aerospace, high-strength fasteners | Welded process piping, pharma, food, offshore |
Mechanical values: Condition A, solution treated (ASTM A564) / Annealed plate, sheet, strip (ASTM A240 / ASME SA240). Limits vary by standard and product form; confirm against your purchase specification.
Frequently asked questions
What is the difference between 17-4PH (SS 630) and SS 316L?
17-4PH (SS 630) is precipitation-hardening stainless; SS 316L is austenitic stainless. SS 316L contains molybdenum (2–3%); 17-4PH (SS 630) has no minimum for it. Nickel: SS 316L 10–14% against 17-4PH (SS 630) 3–5%. Carbon: 17-4PH (SS 630) ≤0.07% against SS 316L ≤0.03%.
Where are 17-4PH (SS 630) and SS 316L used?
17-4PH (SS 630): Shafts, valve stems, aerospace, high-strength fasteners. SS 316L: Welded process piping, pharma, food, offshore.
Can SS 316L replace 17-4PH (SS 630)?
Only if the purchase specification allows it. Check the governing standard, chemistry limits and mechanical properties against the order, and confirm on the mill test certificate.
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Mill test certificate (EN 10204 3.1) supplied with material; third-party inspection on request.
Reference basis: Compiled by Steel Impex India. Check each table’s source, product form and delivery condition before use. Sources, calculation methods and corrections.