- Grade / Alloy
- 420F
- EN / W.Nr.
- 1.4029X29CrS13
- AISI / SAE
- 420F
- UNS
- S42020
- Other names
- 420BF
- Family
- Martensitic
Chemical composition
Chemical composition
Composition limitsComposition limits for long products within EN 10088-3:2014.
| Element | Content (% by mass) |
|---|---|
| CCarbon | 0.25–0.32 |
| SiSilicon | ≤ 1 |
| MnManganese | ≤ 1.5 |
| PPhosphorus | ≤ 0.04 |
| SSulfur | 0.15–0.25 |
| CrChromium | 12–13.5 |
| MoMolybdenum | ≤ 0.6 |
Values describe the grade, not the analysis of a specific batch. The applicable product specification and material certificate determine acceptance. A dash does not mean zero.
What does 420F change?
The 420 family includes chromium stainless steels that can be hardened by heat treatment. Grade 1.4029 adds sulfur for machinability, creating a distinct option for small components machined from bar that also require hardness. The short name X29CrS13 distinguishes it from the 1.4021, 1.4028 and 1.4034 designations found under the general 420 name.
An approximate material-family conversion, not a test result for this grade.
Applications in mechanical components
Applications include shafts, pins, fittings and various turned machine parts. Surface hardness and internal strength depend on the material condition. Annealed and quenched-and-tempered products therefore do not have identical properties. The 420F name alone does not guarantee a particular hardness.
How it differs from 416 and 430F
416 is also a sulfur-bearing martensitic stainless steel, but 1.4029 has a higher carbon range. Grade 430F / 1.4105 is a ferritic designation with different carbon limits. Shared machinability does not establish the same hardening behaviour. The effects of sulfur on corrosion resistance and weldability are also relevant limitations.
Mechanical properties depend on heat treatment
This range is for the stated long-product conditions, +QT850 and sections up to 160 mm under EN 10088-3:2014. It does not apply to annealed material. Elongation refers to longitudinal testing.
| Property | Value |
|---|---|
| Tensile strength Rm | 850–1,000 MPa |
| Proof strength Rp0.2 | ≥ 650 MPa |
| Elongation A | ≥ 9% |
Typical application areas
Shafts and pins, turned mechanical components.
Product and cutting options
Relevant product forms for this material are listed below. Availability varies with grade and dimensions.