H12 vs H10
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.
H12
Tool Steel
H12 is an H13-family hot work steel with about 1.5% tungsten added and slightly less vanadium. The tungsten improves resistance to softening while toughness stays high, suiting severe thermal shock duty.
Standards: DIN 1.2606 · AISI H12 · JIS SKD62 · GB 4Cr5MoWSiV (near)
H10
Tool Steel
H10 is a Cr-Mo hot work steel with lower chromium and higher molybdenum than H13, giving it better thermal conductivity and heat-check resistance in water-cooled dies. It is a long-standing choice for brass and aluminum extrusion tooling.
Standards: DIN 1.2365 · AISI H10 · JIS SKD7 · GB 3Cr3Mo3V (near)
Chemical composition compared (%)
| Element | H12 | H10 |
|---|---|---|
| C | 0.30–0.40 | 0.35–0.45 |
| Si | 0.80–1.25 | 0.80–1.20 |
| Mn | 0.20–0.60 | 0.20–0.50 |
| Cr | 4.75–5.50 | 3.00–3.75 |
| Mo | 1.25–1.75 | 2.00–3.00 |
| W | 1.00–1.75 | — |
| V | 0.20–0.50 | 0.25–0.75 |
Properties compared
| Property | H12 | H10 |
|---|---|---|
| Delivery condition | Annealed | Annealed |
| Working hardness | 40–52 HRC | 38–50 HRC |
| Density | 7.80 g/cm³ | 7.80 g/cm³ |
| Toughness | Better than H13 at equal hardness | — |
| Thermal fatigue | — | Excellent for hot work |
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: H12 · H10. Substitution decisions for certified parts stay with the design authority.