Tool Steel
P20
The pre-hardened mold steel: supplied ready to machine at ~30 HRC, so molds are cut and used without further heat treatment. The standard plastic-mold base steel.
Last verified: 2026-07-10
| AISI classTool-steel group (hardening method / application). | P — mold steel |
|---|---|
| Carbon(%C)Nominal carbon content. | 0.35 |
| Key alloyingPrincipal alloying elements (nominal). | Cr, Mo |
| Working hardness(HRC)Typical hardened + tempered working range. | 28–34 |
| Wear resistance | Moderate |
| Toughness | Good |
| Typical uses | Plastic injection molds, die holders, mold bases, zinc die-cast dies |
- Typical uses: plastic injection and blow molds, mold bases, die holders, low-temperature die-casting dies.
- Supplied pre-hardened (~30 HRC) — machine the cavity and run it; no post-machining heat treat.
- Polishes and textures well for mold finishes; can be nitrided for a harder wear surface.
Other tool steels
Sources
- AISI tool-steel classification (type letters and nominal compositions)
- ASM International — Tool Steels / Heat Treater's Guide (typical properties and working hardness)