EN 10253-2 Type B 316 · X5CrNiMo17-12-2 PRE ~24 · Mo 2.0–2.5%

1.4401 (316) Pipe Fittings

EN 10253-2 Type B buttweld pipe fittings in 1.4401 — standard 316 stainless steel (X5CrNiMo17-12-2, S31600). Mo 2.0–2.5% gives PRE ~24 — same as 316L. For welded pipe systems, 1.4404 (316L, C ≤0.030%) is preferred to prevent weld sensitisation.

PRE (approx.)

~24

Mo Content

2.0–2.5%

ASTM Equivalent

A403 WP316

Prefer 1.4404 (316L) for Welded Service

1.4401 has C ≤0.070%. At this carbon level, welding causes sensitisation — chromium carbide precipitation at grain boundaries depletes the chromium passive layer in the heat-affected zone. 1.4404 (316L) has C ≤0.030%, which eliminates sensitisation without solution annealing. Same Mo, same PRE, same corrosion resistance — 1.4404 is the correct grade for welded piping systems.

316 Family Comparison

W.Nr.	Name	C max	Mo %	PRE	Best Use
1.4401	316	0.070%	2.0–2.5%	~24	Non-welded / solution-annealed
1.4404	316L	0.030%	2.0–2.5%	~24	Welded piping — preferred
1.4432	316L Hi-Mo	0.030%	2.5–3.0%	~26	Elevated chloride
1.4571	316Ti	0.080%	2.0–2.5%	~24	DE/AT/IT specs — Ti stabilised

Cross-References

W.Nr.	1.4401
EN Name	X5CrNiMo17-12-2
ASTM UNS	S31600
ASTM Grade	A403 WP316

Recommended Alternative

For welded service specify 1.4404 (316L). Same PRE, same Mo, same corrosion resistance — C ≤0.030% eliminates sensitisation.

1.4404 (316L) grade page →

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