P20 / 40CrMnMo7
1.2311Pre-hardened plastic mold steel (usually delivered at 28-34 HRC). The most widely used mold base steel globally. Good machinability in pre-hardened condition, good polishability. Used for injection molds, die-casting dies, extrusion tooling, and structural mold components.
International equivalents
| Flag | Standard | Country | Grade | Number | Match |
|---|---|---|---|---|---|
| 🇺🇸 | AISI | USA | AISI P20 | T51620 | REF |
| 🇪🇺 | EN | Europe | 40CrMnMo7 | 1.2311 | 100% |
| 🇨🇳 | GB | China | 3Cr2Mo | — | 90% |
| 🇯🇵 | JIS | Japan | SCM440 (modified) | — | 80% |
Sources: ASTM A681, EN ISO 4957, GB/T 1299, JIS G4105
Chemical composition comparison (wt%)
Side-by-side: P20 / 40CrMnMo7 (EN) (EN ISO 4957) vs 3Cr2Mo (GB)
| Element | P20 / 40CrMnMo7 (EN) | 3Cr2Mo (GB) | Overlap |
|---|---|---|---|
| C | 0.35–0.45% | — | — |
| Si | 0.2–0.4% | — | — |
| Mn | 1.3–1.6% | — | — |
| P | 0–0.03% | — | — |
| S | 0–0.03% | — | — |
| Cr | 1.8–2.1% | — | — |
| Mo | 0.15–0.25% | — | — |
Mechanical properties
Pre-hardened (delivered)
| Property | Value | Unit |
|---|---|---|
| Hardness HRC | 28–34 | HRC |
| Tensile Strength | 900–1100 | MPa |
| Yield Strength | ≥ 700 | MPa |
| Elastic Modulus | ≥ 210 | GPa |
| Density | ≥ 7.85 | g/cm3 |
Heat treatment
| Process | Temperature | Medium | Holding Time | Notes |
|---|---|---|---|---|
| quenching | 840–870 °C | oil | min 30 min | Usually delivered pre-hardened — rehardening rarely needed |
| tempering | 540–620 °C | air | min 60 min | Double tempering recommended. 580°C typical for 30 HRC |
| annealing | 710–740 °C | furnace | Several hours | Soft annealing. Cool slowly in furnace. |
| stress_relief | 550–600 °C | furnace | 2 hours minimum | After rough machining, before finish machining |
Compatibility verdict
P20 / 40CrMnMo7 and 3Cr2Mo: 90% composition match
Close equivalents but NOT identical.
Related materials
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1.3343The most widely used high-speed steel worldwide. W-Mo-Cr-V composition gives excellent red hardness (cuts at temperatures up to 600°C). Used for twist drills, end mills, taps, reamers, bandsaw blades, and general-purpose cutting tools. The benchmark HSS grade.
X45NiCrMo4
1.2767Nickel cold-work tool steel with exceptional toughness from ~4% Ni content. Excellent through-hardenability, polishability, and impact resistance. Used for plastic injection molds (high-gloss), embossing dies, scrap shear blades, punches, cutlery dies, and bending tools.
H11 / X38CrMoV5-1
1.2343Cr-Mo-V hot-work tool steel — close relative of H13 with slightly lower C and V. Good hot hardness, thermal fatigue resistance and toughness. Used for forging dies, extrusion tooling, mandrels, and die-casting tools. Often preferred over H13 where higher toughness is needed.
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