316 vs 316L: differences explained
316 vs 316L: the same 16.5–18.5 Cr, 10–13 Ni, 2–2.5 Mo alloy with carbon capped at 0.08 % or at 0.030 % — a difference that only shows at the weld.
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Overview
The L is low carbon, and that is the entire difference: 316 allows up to 0.08 % carbon, 316L up to 0.030 %. Chromium, nickel and molybdenum are the same in both, so corrosion resistance in the base metal is the same in both.
The carbon matters when the steel is held between roughly 425 and 815 °C — which is what a weld does to the metal beside it. At those temperatures chromium and carbon combine at the grain boundaries, and the chromium that goes into carbides is no longer available to protect the steel. The result, sensitisation, shows up as corrosion in a narrow band parallel to the weld rather than in the weld itself. Less carbon means less to precipitate, which is why 316L is the default for welded fabrication.
In practice most modern material settles the argument for you: it is dual certified 316/316L, meaning the carbon is below 0.030 % and the mechanical properties still meet the higher 316 minimums.
316 vs 316L side by side
| Property | 316 | 316L |
|---|---|---|
| EN number | 1.4401 | 1.4404 |
| Max carbon | 0.08 % | 0.030 % |
| Chromium | 16.5–18.5 % | 16.5–18.5 % |
| Nickel | 10.0–13.0 % | 10.0–13.0 % |
| Molybdenum | 2.0–2.5 % | 2.0–2.5 % |
| Yield Rp0.2 (ASTM min.) | 205 MPa | 170 MPa |
| Tensile Rm (ASTM min.) | 515 MPa | 485 MPa |
| Elongation | 40 % min. | 40 % min. |
| PREN (approx.) | 24–25 | 24–25 |
| Corrosion, base metal | Same as 316L | Same as 316 |
| Corrosion after welding | Risk of sensitisation in the heat-affected zone | Effectively immune at normal section thicknesses |
| Post-weld solution anneal | Recommended on heavy sections | Not required |
| Service above 500 °C | Better — higher creep strength | Lower creep strength; avoid for sustained high temperature |
| Preferred for | Unwelded parts, high temperature, where strength governs | Welded fabrication, thick sections, pharmaceutical and food plant |
| Machining | Marginally easier — slightly higher carbon | Slightly gummier |
| Cost | Effectively identical | Effectively identical |
| Grade above for heat | 316H (0.04–0.10 % C) | 316H (a 316 variant, not a 316L one) |
| JIS equivalent | SUS 316 | SUS 316L |
| Common delivery | Often supplied as dual-certified 316/316L | Often supplied as dual-certified 316/316L |
| Typical price | Same class; surcharge follows nickel and molybdenum | Same class; surcharge follows nickel and molybdenum |
Which should you choose?
Specify 316L for anything welded and 316 for anything hot. For tanks, pipework, pharmaceutical and food plant, handrail and any fabrication going into service without a post-weld solution anneal, 316L removes a failure mode for no cost. For unwelded machined parts, and for sustained service above about 500 °C where creep strength governs, 316 — or 316H — is the correct choice.
If the certificate says 316/316L dual, the material satisfies both and the question does not arise.
- Sustained service above roughly 500 °C, where creep strength matters
- Unwelded machined components where the higher minimum yield is used in design
- Parts that will be solution annealed after fabrication anyway
- Applications where a design code calls up the 205 MPa yield explicitly
- Bar stock for turning, where the slightly higher carbon machines a little better
- Any welded fabrication that will not be post-weld annealed
- Thick sections, where the heat-affected zone spends longer in the sensitisation range
- Pharmaceutical, dairy and food plant with cleaning chemicals and no tolerance for weld-line corrosion
- Marine and chloride service where welds sit in the wetted zone
- Repair welding on existing 316 equipment
Frequently asked questions
What does the L mean in 316L?
Low carbon: a maximum of 0.030 % against 0.08 % for 316. Everything else in the alloy — 16.5–18.5 % chromium, 10–13 % nickel, 2–2.5 % molybdenum — is the same, so the L affects welding behaviour, not base-metal corrosion resistance.
Is 316L more corrosion resistant than 316?
Not in the base metal, where they are identical. The difference appears beside a weld: 316's higher carbon can precipitate chromium carbides at the grain boundaries, leaving a chromium-depleted band that corrodes. 316L has too little carbon for that to matter.
Is 316 stronger than 316L?
Slightly, on paper. ASTM A240 gives 316 a minimum yield of 205 MPa and tensile of 515 MPa, against 170 and 485 MPa for 316L. Real material usually exceeds both, which is why dual-certified stock meeting the 316 minimums at 316L carbon is common.
What is dual certified 316/316L?
Material whose carbon is below 0.030 % — satisfying 316L — while its mechanical properties still meet the higher 316 minimums. One certificate then covers both specifications, which is why most 316 sold today is supplied this way.
Which should be used for welded pipework?
316L, unless the fabrication will be solution annealed after welding. It removes the sensitisation risk in the heat-affected zone at effectively no price difference, which is why process, food and pharmaceutical pipework is specified in 316L as a matter of routine.
Can 316L be used at high temperature?
For short excursions, yes; for sustained service above about 500 °C, no. Low carbon means lower creep strength, so the grade to specify for hot service is 316 or, where a design code allows it, 316H with its deliberately raised carbon range.
Related comparisons
Verified against EN 10088-2:2014 · ASTM A240/A240M. Last checked: November 2026.