EN 10253-4 Type B 316 · X5CrNiMo17-12-2 PRE ~24 · Mo 2.0–2.5%

1.4401 (316) Pipe Fittings

EN 10253-4 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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Testing & Inspection

✓ Chemical analysis against EN 10216-5 / EN 10253
✓ Tensile test, with impact test where the standard or your order requires it
✓ Intergranular corrosion test when specified
✓ PMI (positive material identification) on every order
✓ Visual and dimensional inspection to EN 10253
✓ NDT (UT, RT, MT or PT) when your order or code calls for it
✓ EN 10204 3.1 certificate as standard; 3.2 with TÜV, Lloyd's Register, Bureau Veritas, DNV or your own inspector

Size Range

DN15–DN600 and larger. Outside diameters follow the EN 10220 / EN ISO 1127 pipe series; wall thickness is matched to your connecting pipe.

Size	OD (mm)
DN 15	21.3
DN 20	26.9
DN 25	33.7
DN 32	42.4
DN 40	48.3
DN 50	60.3
DN 65	76.1
DN 80	88.9
DN 100	114.3
DN 125	139.7
DN 150	168.3
DN 200	219.1
DN 250	273.0
DN 300	323.9
DN 350	355.6
DN 400	406.4
DN 450	457.0
DN 500	508.0
DN 600	610.0

Export Documents & Packing

✓ Commercial invoice, packing list and certificate of origin
✓ EN 10204 certificates with heat-number traceability
✓ PED 2014/68/EU and AD 2000-Merkblatt W0 documentation for European projects
✓ Seaworthy wooden cases or pallets, bevel ends protected, marked to your instructions
✓ FOB, CFR or CIF delivery terms

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Frequently Asked Questions: 1.4401 (316) Fittings

What is the difference between 1.4401 (316) and 1.4404 (316L)?

Both have 2.0–2.5% molybdenum and a PRE of about 24. For welded piping, low-carbon 1.4404 (C ≤ 0.030%) is preferred to prevent weld sensitisation.

What is the designation of 1.4401?

X5CrNiMo17-12-2 (UNS S31600).

Which certificates come with 1.4401 fittings?

EN 10204 3.1 as standard, or 3.2 with third-party inspection.