1040 vs 1045
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.
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
1045
Carbon Steel
1045 is the world’s most common medium-carbon steel — the default for shafts, hydraulic rods and plates that need more strength than mild steel, with optional induction hardening.
Standards: DIN 1.0503 (C45) · AISI 1045 · JIS S45C · GB 45
Chemical composition compared (%)
| Element | 1040 | 1045 |
|---|---|---|
| C | 0.37–0.44 | 0.43–0.50 |
| Mn | 0.60–0.90 | 0.60–0.90 |
| P | ≤0.040 | ≤0.040 |
| S | ≤0.050 | ≤0.050 |
| Si | — | 0.15–0.35 (typ.) |
Properties compared
| Property | 1040 | 1045 |
|---|---|---|
| Tensile strength | 570–660 MPa (normalized, typ.) | 570–700 MPa (normalized) |
| Density | 7.85 g/cm³ | 7.85 g/cm³ |
| Hardness | — | 170–210 HB (normalized); 50+ HRC surface by induction |
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: 1040 · 1045. Substitution decisions for certified parts stay with the design authority.