316 vs 321 Stainless Steel
When chloride resistance meets high-temperature stabilization — PMI decision guide.
Key Differences
| Property | 316 | 321 |
|---|---|---|
| ---------- | ----- | ----- |
| Mo | ~2–3% | — |
| Ti | — | ≥0.4% |
| Chloride resistance | Excellent | Good (not Mo-enhanced) |
| High-temp service | Good | Better (Ti stabilized) |
| Typical use | Marine, pharma | Exhaust, heat exchangers |
PMI note
316 is identified by Mo. 321 overlaps 304 on Cr-Ni — use application context and Grade ID libraries for high-temp assets.