420F vs 420
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.
420F
Stainless Steel
420F is the free-machining version of 420, resulfurized (0.15% S minimum) so that hardened stainless parts can be produced economically on automatic lathes. It keeps 420’s hardenability to around 50 HRC but gives up corrosion resistance and weldability for chip-breaking.
Standards: AISI 420F (UNS S42020) · JIS SUS420F
420
Stainless Steel
420 is a hardenable 13% chromium martensitic stainless used for cutlery, surgical instruments and wear parts. Note: DIN 1.2083 is the high-carbon (0.36–0.42% C) mold-steel variant of the 420 family, melted and specified for plastic mold cavities rather than general engineering use.
Standards: DIN 1.4021 · AISI 420 · JIS SUS420J1 · GB 20Cr13
Chemical composition compared (%)
| Element | 420F | 420 |
|---|---|---|
| C | ≥0.15 | ≥0.15 |
| Si | ≤1.00 | ≤1.00 |
| Mn | ≤1.25 | ≤1.00 |
| P | ≤0.060 | ≤0.040 |
| S | ≥0.15 | ≤0.030 |
| Cr | 12.00–14.00 | 12.00–14.00 |
| Mo | ≤0.60 | — |
Properties compared
| Property | 420F | 420 |
|---|---|---|
| Delivery condition | Annealed (hardened for use) | Annealed (hardened for use) |
| Hardness (hardened) | 40–52 HRC typical | 48–55 HRC |
| Density | 7.70 g/cm³ | 7.70 g/cm³ |
| Magnetic | Yes | Yes |
| Tensile strength | — | 655–1700 MPa (condition dependent) |
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: 420F · 420. Substitution decisions for certified parts stay with the design authority.