L6 vs 5CrNiMo
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.
L6
Tool Steel
L6 is a nickel-chromium oil-hardening steel prized for toughness in large tools. The nickel content deepens hardening and keeps big sections from going brittle.
Standards: DIN 1.2714 (family) · AISI L6 · JIS SKT4 (near) · GB 5CrNiMo (near)
5CrNiMo
Tool Steel
5CrNiMo is China’s standard hammer forging die steel (GB/T 1299), a Ni-Cr-Mo grade that through-hardens in very large die blocks while staying tough. It has served Chinese forge shops for decades as the default die-block material.
Standards: DIN 1.2713 (55NiCrMoV6, close) · AISI L6 (family) · JIS SKT4 · GB 5CrNiMo
Chemical composition compared (%)
| Element | L6 | 5CrNiMo |
|---|---|---|
| C | 0.65–0.75 | 0.50–0.60 |
| Si | 0.10–0.50 | 0.15–0.35 |
| Mn | 0.25–0.80 | 0.50–0.80 |
| Cr | 0.60–1.00 | 0.50–0.80 |
| Ni | 1.25–2.00 | 1.40–1.80 |
| Mo | ≤0.50 | 0.15–0.30 |
Properties compared
| Property | L6 | 5CrNiMo |
|---|---|---|
| Delivery condition | Annealed | Annealed or prehardened |
| Hardness (hardened) | 50–58 HRC | — |
| Density | 7.85 g/cm³ | 7.85 g/cm³ |
| Toughness | Very high (nickel-bearing) | Very high in large blocks |
| Working hardness | — | 34–44 HRC (forging dies) |
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: L6 · 5CrNiMo. Substitution decisions for certified parts stay with the design authority.