Last verified 19 August 2026.
The comparison
| Property | 304L | 441 | Evidence |
|---|---|---|---|
| Proof strength Rp0.2, minimum (EN) | 220 MPa | 250 MPa | E3 E3 |
| Tensile strength Rm, minimum | 520 MPa | 430 MPa | E3 E3 |
| Elongation A, minimum | 45 % | 18 % | E3 E3 |
| PREN | 18 — | 18 — | E3 E3 |
| Density | 7.9 g/cm³ | 7.7 g/cm³ | E3 E3 |
| Modulus of elasticity | 200 GPa | 220 GPa | E3 E3 |
| Thermal conductivity | 15 W/(m·K) | 25 W/(m·K) | E3 E3 |
| Proof strength Rp0.2, longitudinal | not established here | 230 MPa | — / E3 |
All shared rows compare like for like.
Where each side’s numbers come from
See 304L and 441 — each page lists every source, every demotion and every gap. Nothing on this page is derived from anything not on those two, and our coverage limits are stated separately.
Where a PREN appears above, read it as a ranking number rather than a qualification: what PREN can and cannot tell you.
When to choose which
304L. Welded fabrication that has to stay corrosion resistant at the weld. That is the whole argument. Everything else about it — price, availability, formability, the fact that every shop already knows how to handle it — is inherited from 304. If a part is welded and will see moisture, specifying 304L costs almost nothing and removes a failure mode that is invisible until it is not.
441. Heat exchange, exhaust and appliance work where the environment is mild but thermal behaviour matters. High conductivity, low expansion, no nickel in the price, and immunity to the chloride stress corrosion cracking that catches austenitics. In flat product at moderate thickness it is often a straight substitution for 304 at a lower and much less volatile cost.
Against 304L: Two reasons, in order of how often they bite. Strength: the EN cold rolled minima are the lowest in the austenitic family, and a strength-driven section in 304L is heavy. Chlorides: with no molybdenum it is no better than 304, and coastal air, de-icing salt and process water all find that out. For welded service in chlorides the honest step up is 316L, not 304L.
Against 441: Thickness, toughness and welding. Ferritics have a ductile-to-brittle transition and it moves up with section thickness, so heavy plate is not the place for them. Weld zones coarsen and lose toughness, which limits practical welded construction. And elongation at 18% is less than half what an austenitic gives, so deep drawing and severe forming go elsewhere.
What this comparison does not cover
- The ASTM plate minima are not established here, and they are the figures most North American projects need.
- The 0.03% carbon maximum that defines the grade is not sourced on this page.
- Elevated and cryogenic temperature behaviour, and the creep range.
- Fatigue, fracture toughness and chloride stress corrosion cracking.
- Sensitisation behaviour after long exposure in the 450–850 °C range, which the low carbon delays rather than prevents. Not sourced here; the standard and the mill datasheet are the routes.
- Whether 304L suits your application. No page can answer that.
- Impact toughness and the transition temperature are not established here, and for a ferritic they govern the safe thickness and the minimum service temperature.
- Elevated temperature strength and creep.
- Welding procedure guidance, which matters more for ferritics than for austenitics.
- Composition limits, not established.
- No ASTM designation or minima on this page.
- Which orientation the higher proof strength figure belongs to. Two sources, one number each way, neither says.
Generated from data/materials/304l.yaml and 441.yaml.