1140 vs 1040
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.
1140
Carbon Steel
1140 is the resulfurized free-machining counterpart of 1040, with the same carbon class but sulfur added for chip breaking. It serves screw-machine production of medium-strength parts.
Standards: AISI 1140
1040
Carbon Steel
1040 is a medium carbon steel for moderately stressed shafts, bolts and gears. It is the plain-carbon predecessor of 5140/40Cr in many cost-sensitive designs, with similar carbon but no chromium hardenability boost.
Standards: DIN 1.0511 (C40) · AISI 1040 · JIS S40C · GB 40
Chemical composition compared (%)
| Element | 1140 | 1040 |
|---|---|---|
| C | 0.37–0.44 | 0.37–0.44 |
| Mn | 0.70–1.00 | 0.60–0.90 |
| P | ≤0.040 | ≤0.040 |
| S | 0.08–0.13 | ≤0.050 |
Properties compared
| Property | 1140 | 1040 |
|---|---|---|
| Tensile strength | 540–640 MPa (hot rolled, typ.) | 570–660 MPa (normalized, typ.) |
| Density | 7.85 g/cm³ | 7.85 g/cm³ |
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: 1140 · 1040. Substitution decisions for certified parts stay with the design authority.