P20 steel is a popular choice for plastic mold makers thanks to its balanced mechanical properties, pre-hardened state, and excellent machinability. It is widely used in medium- to high-end molds, especially for applications requiring long-term stable performance.
1. Core Characteristics: Balancing Performance and Practicality
Key features of P20 steel include:
- Pre-hardened steel: Delivered at HRC 28–32, eliminating complex quenching processes and reducing the risk of mold deformation.
- Alloyed for toughness: Contains chromium and nickel for hardness, wear resistance, and resistance to cracking under high-frequency injection molding.
- Balanced performance: Offers both durability and resistance to damage during repeated use.
P20 steel perfectly balances the core requirements of molds: long service life and reliable performance.

2. Machining and Surface Treatment:
P20 steel offers excellent machinability for mold production:
- Low cutting resistance: Reduces tool wear and enables efficient milling of complex cavities and contours.
- Precision surface finish: Polishing can achieve ≤Ra0.8μm, ensuring smooth demolding and scratch-free plastic parts.
- Optional surface treatments: Nitriding or similar processes can increase wear resistance, extending mold life by 30% or more without using costlier steels.
Applications:
- Complex-cavity plastic molds
- Medium- to high-end injection molds
- Medium- to high-end injection molds

3. Why P20 Steel is a Mainstream Choice
- No quenching required: Simplifies mold production and shortens lead times.
- Easy to machine: Reduces labor and processing costs.
- Stable and reliable: Maintains consistent mold quality during long-term production.
- Cost-effective: Balances performance and affordability for mainstream mold manufacturing.
Conclusion
P20 steel is a fundamental and widely used material in plastic mold manufacturing, offering pre-hardened durability, easy machinability, and reliable performance. Using P20 steel helps manufacturers shorten production cycles, reduce costs, and maintain stable mold quality.