SS 304 vs SS 304L
SS 304L is the low-carbon version of SS 304 — the "L" stands for "low carbon" (max 0.03% vs 0.08% in standard 304). The lower carbon prevents carbide precipitation during welding, which would otherwise cause intergranular corrosion in the heat-affected zone.
Side-by-side comparison
| Attribute | SS 304 | SS 304L |
|---|---|---|
| Carbon (C) max | 0.08% | 0.03% |
| Chromium | 18–20% | 18–20% |
| Nickel | 8–10.5% | 8–12% |
| Tensile strength | ≥ 515 MPa | ≥ 485 MPa |
| Yield strength | ≥ 205 MPa | ≥ 170 MPa |
| Weldability | Good | Excellent (no post-weld annealing needed) |
| Intergranular corrosion | Possible after welding | Highly resistant |
| Typical price | Baseline | ~5–8% more |
| Best for | General fabrication, machined parts | Welded fabrication, pressure vessels, pipework |
When to choose SS 304
Choose SS 304 for non-welded or lightly-welded parts where mechanical strength matters more than weld-zone corrosion — machined components, fasteners, decorative hardware.
Buy SS 304 on MetaleMartWhen to choose SS 304L
Choose SS 304L for any heavily-welded fabrication — pressure vessels, piping, tanks, food processing equipment — especially where post-weld heat treatment is impractical.
Buy SS 304L on MetaleMartFrequently asked questions
Can SS 304L replace SS 304?
In most applications, yes — 304L meets or exceeds 304 in corrosion resistance. The only trade-off is slightly lower yield strength, which matters only in load-bearing parts.
Why does carbon content matter for welding?
During welding, carbon in 304 can combine with chromium to form chromium carbides at grain boundaries, depleting the surrounding metal of chromium and causing rapid corrosion. Low carbon in 304L prevents this.
Is 304L more expensive?
Yes, marginally — typically 5–8% more than 304 due to tighter chemistry control during melting.