X5CrNi18-10 · S30400 · 18-8 Austenitic Stainless Steel · EN 10253-2 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 / 304L (S30400/S30403) |
| PRE (typical) | ~18 (no Mo) |
| Cryogenic temp | −196°C (Charpy ok) |
| Filler (GTAW) | ER308L |
| PWHT | Not required |
| Standard | EN 10253-2 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.
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