# 440C stainless steel equivalents

440C stainless steel is nearest to EN 1.4125 (X105CrMo17), JIS SUS440C and China GB 108Cr17. These are nearest equivalents, not identical grades: the governing standard or mill certificate decides.

| System | Designation |
|---|---|
| AISI / ASTM / SAE | 440C |
| EN steel name | X105CrMo17 |
| EN steel number | 1.4125 |
| JIS | SUS440C |
| China GB | 108Cr17 |

Family: Martensitic stainless, high carbon

## What it is

A high-carbon martensitic stainless steel. It reaches the highest hardness and wear resistance of the standard stainless grades, with moderate corrosion resistance.

## Typical uses

Stainless ball bearings and races, valve seats, nozzles, knife blades and wear parts in mildly corrosive service.

## Machining notes

Machine in the annealed condition and leave grinding stock: after hardening it is finished by grinding.

## Related grades

- 420 stainless steel (1.4021): Lower-carbon martensitic grade, easier to machine
- 52100 steel (1.3505): Standard non-stainless bearing steel

Equivalents are nearest matches, not identical grades. The governing standard or mill certificate decides.

## FAQ

**What is the European equivalent of 440C stainless steel?**
The nearest EN grade is 1.4125, steel name X105CrMo17.

**What is the JIS equivalent of 440C stainless steel?**
The nearest Japanese grade is SUS440C.

**What is the Chinese GB equivalent of 440C stainless steel?**
The nearest Chinese GB grade is 108Cr17.

**Is 1.4125 the same as 440C?**
1.4125 (X105CrMo17) is the nearest European equivalent of 440C, not an identical grade. Composition limits and required properties differ in detail, so check the governing standard or the mill certificate when it matters.

**What is 440C used for?**
Stainless ball bearings and races, valve seats, nozzles, knife blades and wear parts in mildly corrosive service.

Source page: https://machinistcharts.com/material/440c-stainless/
Updated: 2026-10-06
Publisher: MachinistCharts (https://machinistcharts.com)