EN 10253-2 Type B buttweld pipe fittings in 1.4436 — 316Mo stainless steel (X3CrNiMo17-13-3). 1.4436 is a higher-molybdenum variant of the 316 family, specifying Mo at 2.5–3.0% minimum (vs 1.4404's 2.0–2.5%). The additional Mo provides marginally improved pitting resistance (PRE ~26 vs ~24) in chloride environments. Commonly specified on European drawings calling for a higher Mo assurance than standard 316L offers.
| Grade | W.Nr. | C max | Mo % | PRE | Distinguishing Feature |
|---|---|---|---|---|---|
| 316 | 1.4401 | 0.070% | 2.0–2.5% | ~23 | Standard; avoid for welded |
| 316L | 1.4404 | 0.030% | 2.0–2.5% | ~24 | Standard low-carbon welded grade |
| 316Mo | 1.4436 | 0.030% | 2.5–3.0% | ~26 | Higher Mo assurance; European specification |
| 316L Hi-Mo | 1.4432 | 0.030% | 2.5–3.0% | ~26 | Similar to 1.4436; check EN spec carefully |
| 316Ti | 1.4571 | 0.080% | 2.0–2.5% | ~24 | Ti-stabilised; high-temperature cycling |
General welded service in mild chloride environments. Lower cost. Standard EN 10253-2 Type B grade for most European applications.
When the specification explicitly calls for 1.4436, or when higher Mo assurance (2.5% min vs 2.0% min) is required. Common in Scandinavian and German offshore and marine specifications. PRE gain is marginal (~2 points) so step up to 1.4462 (Duplex) if significant corrosion resistance improvement is needed.
| W.Nr. | 1.4436 |
| EN Name | X3CrNiMo17-13-3 |
| Common Name | 316Mo / 316L Hi-Mo |
Filler: ER316L (AWS A5.9). No PWHT required. Same welding procedures as 316L apply.
