X5CrNi18-10 · S30400 · 18-8 Austenitic Stainless Steel · EN 10253-4 Type B
The most widely produced austenitic stainless steel. General-purpose corrosion resistance, excellent weldability, cryogenic toughness. The base grade for food, water, and general process piping where chloride levels are low.
1.4301 (ASTM 304, UNS S30400) is the archetypal 18% Cr – 8% Ni austenitic stainless steel. It provides general corrosion resistance in atmospheric, freshwater, mild acid, and food-grade environments without the cost of molybdenum-bearing grades. The 304L sub-grade limits carbon to ≤0.030% — preventing sensitisation in the HAZ after welding without requiring post-weld solution annealing.
The key limitation is susceptibility to chloride-induced pitting above approximately 200 ppm Cl⁻ at ambient temperature, and to chloride stress corrosion cracking (SCC) above about 60°C. For seawater, marine, or chloride-containing process environments, 316L (1.4404) or higher grades are required.
| Element | 304 (1.4301) | 304L (1.4306) | Note |
|---|---|---|---|
| Carbon (C) | ≤0.07% | ≤0.030% | Low C in L grade prevents sensitisation |
| Chromium (Cr) | 17.5–19.5% | 17.5–19.5% | Passivation |
| Nickel (Ni) | 8.0–10.5% | 8.0–12.0% | Austenite stabiliser |
| Manganese (Mn) | ≤2.0% | ≤2.0% | — |
| Silicon (Si) | ≤1.0% | ≤1.0% | — |
| Molybdenum (Mo) | — | — | No Mo — pitting limitation |
| EN number | 1.4301 |
| EN designation | X5CrNi18-10 |
| ASTM equivalent | 304 (S30400) |
| PRE (typical) | ~18 (no Mo) |
| Cryogenic temp | −196°C (Charpy ok) |
| Filler (GTAW) | ER308L |
| PWHT | Not required |
| Standard | EN 10253-4 Type B |
| Certificate | EN 10204 3.1 standard |
Delta ferrite FN report, Ra surface finish, and Charpy cryogenic impact testing available. EN 10204 3.1 standard on every order.
Get QuoteDN15–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 |
304 (UNS S30400); EN designation X5CrNi18-10. Low-carbon 304L is 1.4307.
Yes, Charpy toughness is retained down to −196°C.
ER308L filler for GTAW; PWHT is not required. It suits low-chloride service; for chlorides, molybdenum grades such as 1.4404 are used.
Supplying an Indian boiler or ASME B16.9 project? The equivalent grade is listed on our group site ibrfittings.com: ASTM A403 WP304 / 304L fittings.
