2205 (UNS S32205/S31803) is a duplex stainless steel with an austenite + ferrite microstructure, used where both chloride resistance and strength matter.

Key differences:

• Strength: 2205 typically exceeds 450 MPa yield strength versus roughly 200–250 MPa for 316L, allowing thinner sections. • Corrosion: PREN around 34–36; better pitting and stress-corrosion-cracking resistance than 316L. • Welding: heat input and interpass temperature must be controlled to keep the ferrite/austenite balance; post-weld solution annealing is usually unnecessary, but the process window is narrower. • Forming: 2205 has more springback and is harder to deep draw.

Choose 2205 for seawater, FGD, chemical tanks and pressure piping in medium-to-high chloride service; stay with 316L for low chloride, complex forming, limited welding capability or tight budgets.

Do not simply copy 316L welding parameters to 2205 — run a welding procedure qualification (WPS/PQR) first.