What is the difference between 1.4307 and 1.4306 (304L)?

Both 1.4307 and 1.4306 are low-carbon 304L grades. 1.4307 (X2CrNi18-9) is the current designation per EN 10088-4 and the preferred grade for fittings — C ≤0.030%, N ≤0.11%, Cr 17.5–19.5%, Ni 8.0–10.5%. 1.4306 (X2CrNi19-11) has slightly higher Ni (10.0–12.0%) and Cr (18.0–20.0%) but similar corrosion resistance. For EN 10253-2 fittings, 1.4307 is the standard 304L designation.

Can 1.4307 (304L) be used for LNG piping at −162°C?

Yes — 1.4307 (304L) is the standard material for LNG piping. Its FCC (face-centred cubic) austenitic crystal structure maintains full ductility at cryogenic temperatures. Charpy V-notch impact energy at −196°C typically exceeds 100J for solution-annealed 304L. The grade is routinely impact-tested at −196°C per EN 10253-2 requirements for cryogenic service. No special cryogenic grade is needed — standard 1.4307 with impact test documentation is correct.

EN 10253-2 Type B 304L · X2CrNi18-9 −196°C Cryogenic

1.4307 (304L) Pipe Fittings

EN 10253-2 Type B buttweld pipe fittings in 1.4307 — the European designation for 304L stainless steel (X2CrNi18-9, S30403). General-purpose austenitic stainless steel without molybdenum. The standard cryogenic-service stainless steel — maintains full ductility at −196°C due to its FCC crystal structure.

PRE (approx.)

~18

Temperature Range

−196°C to +400°C

ASTM Equivalent

A403 WP304L

Chemistry (EN 10088-4 Limits)

Element	Min	Max	Function
C (Carbon)	—	0.030%	Low C prevents sensitisation in welded service
Cr (Chromium)	17.5%	19.5%	Passive oxide film — primary corrosion protection
Ni (Nickel)	8.0%	10.5%	Austenite stabiliser; SCC resistance
Mo (Molybdenum)	—	—	None — 304L has no Mo (vs 316L)
N (Nitrogen)	—	0.11%	Mild PRE enhancement
Mn	—	2.0%	—
Si	—	1.0%	—

304L vs 316L — When to Use Which

Property	1.4307 (304L)	1.4404 (316L)
Mo content	None	2.0–2.5%
PRE	~18	~24
Cryogenic suitability	Excellent (−196°C)	Excellent (−196°C)
Chloride resistance	Low — not for seawater	Moderate — mild chloride
Cost	Lower (no Mo)	Higher
Use for LNG piping	Yes — preferred	Yes — if chloride present
Use for food/pharma utility	Yes	Yes (higher cost for same result)

Key Applications

LNG Terminals & Cryogenic

LNG transfer piping, liquid nitrogen, liquid argon, LOX service. Impact-tested at −196°C. FCC austenitic structure — no ductile-to-brittle transition.

Food & Beverage

Brewing, dairy, beverage processing, water treatment. No Mo — cost-optimal where chloride resistance is not required.

General Utility

Plant utility water, non-chloride process, instrument air, nitrogen purge lines, clean condensate. Standard choice for non-aggressive service.

Pharmaceutical Utility

Non-product-contact cooling water, secondary utility. Use 1.4435 (≤1 FN) for WFI contact — 1.4307 for utility loops only.

Cross-References

W.Nr.	1.4307
EN Name	X2CrNi18-9
ASTM UNS	S30403
ASTM Grade	A403 WP304L
Common Name	304L

Welding

Filler: ER308L (AWS A5.9). Low-carbon filler matches base metal carbon control — no PWHT required for austenitic stainless. Solution anneal if sensitisation risk in heat-affected zone for critical service.

Available Fittings

90° Elbows (LR/SR) · 45° Elbows · Equal Tees · Reducing Tees · Concentric Reducers · Eccentric Reducers · Pipe Caps · Stub Ends per EN 10253-2 Type B

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