446 vs 439
These two grades are listed as equivalents of each other: their chemistry windows overlap and they serve the same applications. They are not always identical — check the differences below before substituting, especially in certified designs.
446
Stainless Steel
446 is a high-chromium ferritic heat-resistant grade with outstanding oxidation and sulfidation resistance at high temperature. Room-temperature ductility and toughness are low, so it serves in static furnace hardware rather than structural parts.
Standards: AISI 446 · JIS SUH446
439
Stainless Steel
439 is a stabilised 17–19% chromium ferritic stainless with low carbon and nitrogen, giving better formability, weldability and corrosion resistance than 430. It is used for exhaust systems and heat-exchanger tubing as a lower-cost alternative to 304.
Standards: DIN 1.4510 · AISI 439 · GB 06Cr17Ti
Chemical composition compared (%)
| Element | 446 | 439 |
|---|---|---|
| C | ≤0.20 | ≤0.03 |
| Si | ≤1.00 | ≤1.00 |
| Mn | ≤1.50 | ≤1.00 |
| P | ≤0.040 | ≤0.040 |
| S | ≤0.030 | ≤0.030 |
| Cr | 23.00–27.00 | 17.00–19.00 |
| N | ≤0.25 | ≤0.03 |
| Ni | — | ≤0.50 |
| Ti | — | 0.20+4×(C+N)–1.10 |
Properties compared
| Property | 446 | 439 |
|---|---|---|
| Delivery condition | Annealed | Annealed |
| Hardness | ≤217 HB (annealed) | ≤183 HB (annealed) |
| Tensile strength | 450–620 MPa | 415–585 MPa |
| Density | 7.70 g/cm³ | 7.70 g/cm³ |
| Magnetic | Yes | Yes |
| Max scaling temperature | ~1035 °C | — |
Sourcing either grade?
Nasteel stocks both families from Shenzhen with EN 10204 3.1 mill certificates by heat number.
Ask for a quotationSee full data sheets: 446 · 439. Substitution decisions for certified parts stay with the design authority.