SS 304 vs SS 304L
SS 304 (UNS S30400) vs SS 304L (UNS S30403): chemical composition and mechanical properties side by side.
- Strength: SS 304L minimum yield is 170 MPa vs 205 MPa for SS 304 (-17%); tensile 485 vs 515 MPa.
- Density: 7.93 vs 7.93 g/cm³ — same weight for the same dimensions.
- Pitting resistance (PREN, min): 17.5 vs 17.5 — equal.
- Typical use: SS 304 — General-purpose 18-8 stainless. SS 304L — Low carbon for welding.
| Property | SS 304 | SS 304L |
|---|---|---|
| Family | Austenitic stainless | Austenitic stainless |
| UNS | S30400 | S30403 |
| EN / W.Nr | 1.4301 X5CrNi18-10 | 1.4307 X2CrNi18-9 |
| Basis spec | ASTM A240 | ASTM A240 |
| Density g/cm³ | 7.93 | 7.93 |
| Chemical composition, % | ||
| C | 0.07 | 0.030 |
| Mn | 2.00 | 2.00 |
| P | 0.045 | 0.045 |
| S | 0.030 | 0.030 |
| Si | 0.75 | 0.75 |
| Cr | 17.5–19.5 | 17.5–19.5 |
| Ni | 8.0–10.5 | 8.0–12.0 |
| N | 0.10 | 0.10 |
| Mechanical properties (min) | ||
| Tensile strength | 515 MPa (75 ksi) | 485 MPa (70 ksi) |
| Yield strength (0.2%) | 205 MPa (30 ksi) | 170 MPa (25 ksi) |
| Elongation | 40% | 40% |
| Hardness (max) | 201 HB | 201 HB |
| PREN (min, from spec) | 17.5 | 17.5 |
Single values are maximums; ranges are min–max; "bal" = balance. Limits are typical of the basis specification for that product form — forgings, pipe and fittings specifications differ slightly. Always check the exact specification, edition and the mill test certificate.
Frequently asked questions
What is the difference between SS 304 and SS 304L?
Strength: SS 304L minimum yield is 170 MPa vs 205 MPa for SS 304 (-17%); tensile 485 vs 515 MPa. Density: 7.93 vs 7.93 g/cm³ — same weight for the same dimensions. Pitting resistance (PREN, min): 17.5 vs 17.5 — equal.
Which is stronger, SS 304 or SS 304L?
SS 304 has the higher minimum yield strength (205 MPa vs 170 MPa).
Last updated 2026-11-02