1566 vs 1065
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.
1566
Carbon Steel
1566 is a high carbon, high manganese steel for springs and wear parts needing deeper hardening than 1065 provides. Its chemistry is close to the GB 65Mn concept under the SAE numbering system.
Standards: AISI 1566 · GB 65Mn (near)
1065
Carbon Steel
1065 is a high carbon spring-range steel, close in carbon to GB 65 steel but with the lower manganese of the SAE series. It is used for springs, blades and wear parts in thin to medium sections.
Standards: DIN C65 type (near) · AISI 1065 · GB 65
Chemical composition compared (%)
| Element | 1566 | 1065 |
|---|---|---|
| C | 0.60–0.71 | 0.60–0.70 |
| Mn | 0.85–1.15 | 0.60–0.90 |
| P | ≤0.040 | ≤0.040 |
| S | ≤0.050 | ≤0.050 |
Properties compared
| Property | 1566 | 1065 |
|---|---|---|
| Tensile strength | 750–900 MPa (normalized, typ.) | 700–850 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: 1566 · 1065. Substitution decisions for certified parts stay with the design authority.