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- P20 plastic mold steel 3Cr2Mo 1.2330 PDS3 35CrMo2
P20 plastic mold steel 3Cr2Mo 1.2330 PDS3 35CrMo2
Details
P20 is a widely used pre-hardened chromium-molybdenum plastic mold steel under ASTM A681 standard. It is delivered in pre-tempered condition without secondary quenching and tempering, featuring uniform hardness, excellent polishability, good texture etching performance and stable dimensional accuracy. It balances machinability, wear resistance and toughness, making it the universal choice for medium and low-volume plastic molds. Its Chinese equivalent grade is 3Cr2Mo, mainly supplied as hot rolled black round bars, flat plates, pre-machined mold blocks and precision ground bright bars.
Chemical Composition of AISI P20 (Mass Fraction, wt.%)
| Element | Content Range | Metallurgical Function |
|---|---|---|
| C | 0.28–0.40% | Moderate carbon ensures uniform pre-hardened hardness without brittleness |
| Si | 0.20–0.80% | Deoxidize molten steel, improve surface finish during polishing |
| Mn | 0.60–1.00% | Refine grains, enhance machinability of pre-hardened stock |
| Cr | 1.40–2.00% | Boost hardness uniformity, wear resistance and corrosion resistance |
| Mo | 0.30–0.55% | Eliminate temper brittleness, stabilize hardness on thick sections |
| P | ≤0.030% | Restrict cold brittleness to avoid crack during engraving and polishing |
| S | ≤0.030% | Strictly controlled to prevent surface defects on etched mold surface |
International Equivalent Grades of P20
| Region | Standard Grade | Material No. & Executive Standard |
|---|---|---|
| USA | AISI P20, UNS T51620 | ASTM A681 mold steel |
| China | 3Cr2Mo | GB/T 1299 plastic mold steel |
| Europe | 1.2330 | EN ISO 4957 |
| Japan | PDS3 | JIS G4404 |
| ISO | ISO 4957 |
Key Performance & Heat Treatment Feature
P20 is factory pre-hardened to HB 280–330 (approx. HRC 28–34), ready for direct CNC machining, texture etching, mirror polishing and EDM without extra heat treatment. Thick mold blocks maintain consistent hardness from surface to core with minimal hardness drop. It can be surface nitrided to raise surface hardness up to HRC 48–52 for molds with higher abrasion requirements. Compared with unhardened mold steel, it shortens mold manufacturing cycle and avoids heat treatment deformation risk. Its weakness is low surface hardness, unsuitable for mass production molds with long-run heavy friction.
Main Application Fields
- Household appliance plastic molds: TV shell, air conditioner casing, washing machine internal parts and cosmetic container molds with medium production volume.
- Automotive interior plastic components: dashboard decorative parts, door panels, plastic lamp housings and small interior trim molds.
- 3C electronics molds: mobile phone middle frame, charger shell, mouse and keyboard plastic molds requiring fine texture etching.
- Daily commodity & packaging molds: bottle caps, plastic toys, kitchen plastic accessories and low-corrosion PVC plastic forming molds.
With short processing cycle, excellent etching & polishing property and cost competitiveness, P20 pre-hardened steel dominates medium-run plastic mold market, widely used by mold factories for consumer plastic product manufacturing.
Contact us
008617701706555
Room 903, Canyang Zone, No.1016 Youyi Road, Baoshan District, Shanghai, P.R.China
