P20
Data verifiedP20 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.
Chemical composition
| Element | Content (%) |
|---|---|
| C | 0.28–0.40 |
| Si | 0.20–0.40 |
| Mn | 0.60–1.00 |
| Cr | 1.40–2.00 |
| Mo | 0.30–0.55 |
Weight percent, per the governing standard ranges. Actual values per heat are on the mill certificate.
Properties
| Delivery condition | Prehardened |
| Hardness | 280–325 HB |
| Tensile strength | 950–1100 MPa |
| Density | 7.85 g/cm³ |
Heat treatment
Supplied prehardened; quench 840–870 °C oil, temper 550–620 °C if re-hardened.
Equivalent grades
| Standard | Designation |
|---|---|
| din | 1.2311 (close) |
| aisi | P20 |
| gb | 3Cr2Mo |
Compare side by side: P20 vs 1.2311 · P20 vs 1.2738 · P20 vs 1.2312
Equivalents overlap in chemistry and use but are not always identical — see our equivalents guide before substituting in certified designs.
Applications & Processing
Applications: Injection molds, compression molds, die casting dies for zinc, mold frames.
Processing: Machines well prehardened; takes a good polish (SPI B-2 and better with the +Ni variant); nitriding and chrome plating are common.
FAQ
- P20 vs 1.2738 — which for large molds?
- 1.2738 (P20+Ni) adds ~1% nickel for through-hardness in thick sections, so it is preferred for large molds above roughly 400 mm thickness.
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Ask for a quotationVisit NasteelSource: ASTM A681 published ranges · Last updated 2026-11-03. Data is indicative — verify critical values against the governing standard and mill certificate before use.