S5 vs S7
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.
S5
Tool Steel
S5 uses about 2% silicon to reach exceptional toughness — in classic tool steel comparisons it tops the shock-resistance chart. It is chosen for the most violent impact tools in the shop.
Standards: DIN — (1.2419 family, near) · AISI S5
S7
Tool Steel
S7 is an air-hardening shock-resisting steel with 3.25% chromium and molybdenum, combining S-class toughness with low distortion and some hot hardness. It bridges cold work, impact tooling and light hot work.
Standards: DIN 1.2357 (close) · AISI S7 · GB 5Cr3Mn1SiMo1 (near)
Chemical composition compared (%)
| Element | S5 | S7 |
|---|---|---|
| C | 0.50–0.65 | 0.45–0.55 |
| Si | 1.75–2.25 | 0.20–1.00 |
| Mn | 0.60–1.00 | 0.20–0.90 |
| Mo | 0.20–0.40 | 1.30–1.80 |
| Cr | — | 3.00–3.50 |
| V | — | ≤0.35 |
Properties compared
| Property | S5 | S7 |
|---|---|---|
| Delivery condition | Annealed | Annealed |
| Hardness (hardened) | 52–59 HRC | 52–60 HRC |
| Density | 7.85 g/cm³ | 7.85 g/cm³ |
| Toughness | Among the highest of all tool steels | Outstanding, air hardening |
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: S5 · S7. Substitution decisions for certified parts stay with the design authority.