P20 vs 1.2312
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.
P20
Mold Steel
P20 is the American prehardened mold steel standard (ASTM A681), a Cr-Mo steel used for plastic injection molds worldwide. It balances machinability, polishability and toughness at moderate cost.
Standards: DIN 1.2311 (close) · AISI P20 · GB 3Cr2Mo
1.2312
Mold Steel
1.2312 is the sulfur-added, free-machining version of 1.2311. The added sulfur dramatically improves machinability, at the cost of polishability and weldability — the standard choice for mold bases and non-cavity parts.
Standards: DIN 1.2312 · AISI P20+S · GB 3Cr2MoS
Chemical composition compared (%)
| Element | P20 | 1.2312 |
|---|---|---|
| C | 0.28–0.40 | 0.35–0.45 |
| Si | 0.20–0.40 | 0.20–0.40 |
| Mn | 0.60–1.00 | 1.40–1.60 |
| Cr | 1.40–2.00 | 1.80–2.00 |
| Mo | 0.30–0.55 | 0.15–0.25 |
| S | — | 0.05–0.10 |
Properties compared
| Property | P20 | 1.2312 |
|---|---|---|
| Delivery condition | Prehardened | Prehardened |
| Hardness | 280–325 HB | 280–325 HB |
| Tensile strength | 950–1100 MPa | 950–1100 MPa |
| 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: P20 · 1.2312. Substitution decisions for certified parts stay with the design authority.