QBQQBQ Soudeur

How to weld stainless steel?

Welding stainless steel (304, 316, 316L) requires special attention to avoid sensitization and distortion.

Recommended processes:

  • GTAW (TIG): for thin sheet and cosmetic work (food, pharmaceutical)
  • GMAW (MIG): For medium to thick sections, with 98% Argon + 2% CO₂ gas
  • SMAW: E308L-16 or E316L-16 electrodes for repairs

Critical points:

  • Heat input: keep it low — stainless distorts easily, and the heat input limit depends on the grade, the process and the WPS. Use a copper heat sink behind the weld
  • Cleaning: Dedicated stainless steel brush (never used on carbon steel — risk of iron contamination)
  • Oxidation color: A successful stainless weld is silver to light gold. Blue or gray = excessive oxidation (too much heat or insufficient gas shielding)
  • Passivation: After welding, a passivation treatment (nitric acid or pickling paste) restores the protective chromium oxide layer

Filler metal:

  • Stainless 304: ER308L rod
  • Stainless 316: ER316L rod
  • The "L" means low carbon (< 0.03%) — prevents chromium carbide precipitation
stainless steel weldingTIG stainless weldingstainless passivationER308L ER316Lstainless sensitization

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