SS321 vs SS316Ti: Chemical Composition

SS321 vs SS316Ti: Chemical Composition

SS321 is a titanium-stabilized 304 series stainless steel (Cr-Ni based).
SS316Ti is a titanium-stabilized 316 series stainless steel (Cr-Ni-Mo based), which retains the corrosion resistance of molybdenum.

Corrosion resistance of SS321: Titanium stabilization makes it outstanding in intergranular corrosion resistance during welding or high temperature (450-800℃).
Corrosion resistance of SS316Ti: Molybdenum (2-3%) significantly improves the ability to resist acid, alkaline and chloride environments, and the pitting resistance index (PREN ≥25) is higher than SS321 (PREN≈19).
Limitations: Long-term high temperature (＞800℃) may cause embrittlement due to σ phase precipitation, but titanium stabilization can alleviate
High temperature performance of SS321: Continuous use temperature 800-900℃, short-term tolerance 925℃, suitable for high temperature cycle or multiple welding scenarios (such as aviation exhaust pipes, heat exchangers).
SS316Ti high temperature performance: recommended operating temperature ≤800℃. Molybdenum migration at high temperature may reduce corrosion resistance, but titanium stabilization prolongs high temperature stability. It is suitable for chemical equipment that requires corrosion resistance + high temperature.