Last verified 19 August 2026.
The comparison
| Property | 441 | 444 | Evidence |
|---|---|---|---|
| Proof strength Rp0.2, minimum (EN) | 250 MPa | 300 MPa | E3 E3 |
| Tensile strength Rm, minimum | 430 MPa | 420 MPa | E3 E3 |
| PREN | 18 — | 25 — | E3 E3 |
| Density | 7.7 g/cm³ | 7.7 g/cm³ | E3 E3 |
| Modulus of elasticity | 220 GPa | 220 GPa | E3 E3 |
| Thermal conductivity | 25 W/(m·K) | 23 W/(m·K) | E3 E3 |
| Proof strength Rp0.2, longitudinal | 230 MPa | not established here | E3 / — |
| Elongation A, minimum | 18 % | not established here | E3 / — |
PREN — different documents — Outokumpu Core range datasheet against Outokumpu Supra range datasheet
Density — different documents — Outokumpu Core range datasheet against Outokumpu Supra range datasheet
Modulus of elasticity — different documents — Outokumpu Core range datasheet against Outokumpu Supra range datasheet
Thermal conductivity — different documents — Outokumpu Core range datasheet against Outokumpu Supra range datasheet
Where each side’s numbers come from
See 441 and 444 — 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
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.
444. Hot water tanks, heat exchangers and process equipment in mild chlorides where nickel price volatility is the problem being solved. It sits at the pitting ranking of 316L without nickel, conducts heat better, expands less and does not suffer chloride stress corrosion cracking — which for a hot water application is the failure mode that actually occurs.
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.
Against 444: Anything that has to be formed hard, welded thick, or stay tough cold. Elongation is not even quoted on the row consulted, weld zones lose toughness, and the transition temperature makes heavy section a bad idea. It is also thinly stocked compared with 316L, so a substitution that works on paper often fails on lead time.
What this comparison does not cover
- 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.
- Elongation is not established here for any product form, and that is the property that decides whether a part can be made.
- Impact toughness and the transition temperature are not established here.
- Whether 444 substitutes for 316L in your service. The pitting ranking numbers are close; the failure modes are not the same.
- Welding procedure guidance and filler selection.
Generated from data/materials/441.yaml and 444.yaml.