SS 420 vs SS 304 difference in composition & properties.
SS 420 is martensitic stainless; SS 304 is austenitic stainless. SS 304 contains nickel (8–10.5%); SS 420 has no minimum for it.
Key differences between SS 420 and SS 304
- SS 420 is martensitic stainless; SS 304 is austenitic stainless.
- SS 304 contains nickel (8–10.5%); SS 420 has no minimum for it.
- Chromium: SS 304 17.5–19.5% against SS 420 12–14%.
- SS 420 contains carbon (≥0.15%); SS 304 has no minimum for it (≤0.07%).
- Density: SS 420 7.74 g/cm³, SS 304 7.93 g/cm³.
SS 420 vs SS 304 chemical composition (weight %)
| Element | SS 420 | SS 304 |
|---|---|---|
| C | ≥0.15 | ≤0.07 |
| Si | ≤1 | ≤0.75 |
| Mn | ≤1 | ≤2 |
| P | ≤0.04 | ≤0.045 |
| S | ≤0.03 | ≤0.03 |
| Cr | 12–14 | 17.5–19.5 |
| Ni | – | 8–10.5 |
| N | – | ≤0.1 |
Mechanical properties, equivalents and uses
| Property | SS 420 | SS 304 |
|---|---|---|
| Family | Martensitic stainless | Austenitic stainless |
| Tensile strength, MPa | – | ≥515 |
| Yield strength, MPa | – | ≥205 |
| Elongation, % | – | ≥40 |
| Hardness | – | ≤201 HB |
| Density, g/cm³ | 7.74 | 7.93 |
| UNS | S42000 | S30400 |
| EN | X20Cr13 / X30Cr13 | X5CrNi18-10 |
| W.Nr | 1.4021 / 1.4028 | 1.4301 |
| JIS | SUS420J1 / SUS420J2 | SUS304 |
| IS (India) | X20Cr13 / X30Cr13 (IS 6911) | X04Cr18Ni10 (IS 6911) |
| AISI / ASTM | AISI 420 | AISI 304 |
| Typical uses | Cutlery, surgical tools, moulds, shafts | Food, dairy, kitchen, water, architecture, general process |
Mechanical values: / 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 SS 420 and SS 304?
SS 420 is martensitic stainless; SS 304 is austenitic stainless. SS 304 contains nickel (8–10.5%); SS 420 has no minimum for it. Chromium: SS 304 17.5–19.5% against SS 420 12–14%. SS 420 contains carbon (≥0.15%); SS 304 has no minimum for it (≤0.07%).
Where are SS 420 and SS 304 used?
SS 420: Cutlery, surgical tools, moulds, shafts. SS 304: Food, dairy, kitchen, water, architecture, general process.
Can SS 304 replace SS 420?
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.