Premium P20+Ni Steel for High-Performance Molds
Discover Aobo Steel’s superior-grade P20+Ni steel, engineered for exceptional durability and machinability in mold applications.
P20+Ni steel is a mirror-finish plastic mold steel developed by enhancing the American P20 steel with the addition of Ni alloy. This steel features high hardenability, excellent polishability, electrical discharge machining (EDM) performance, and texturing properties. Pre-hardened with high purity and uniform structure, it is ideal for high-demand plastic molds, particularly those requiring electrical discharge machining.
The applications of P20+Ni steel


Ideal for manufacturing complex and high-precision plastic molds.
Suitable for large-scale mirror-finish plastic mold production.
Why choose Aobo Steel as your P20+Ni supplier
Under the premise of ensuring quality, our prices are approximately 3% lower than the market price.
Before shipment, all goods undergo 100% strict component, UT, and hardness testing.
The goods are strictly reinforced during container loading to ensure safe sea transportation.
P20+Ni steel overview
P20+Ni steel chemical composition
Węgiel (C) | Krzem (Si) | Mangan (Mn) | Fosfor (P) | Siarka (S) | Chrom (Cr) | Molybdenum (Mo) | Nickel (Ni) |
0.35 – 0.45 | 0.20 – 0.40 | 0.60 – 1.60 | ≤ 0.030 | ≤ 0.030 | 1.80 – 2.10 | 0.15 – 0.25 | 0.90 – 1.20 |
P20+Ni steel physical properties
Własność | Wartość | Unit |
Gęstość | 7.7 – 7.85 | g/cm³ |
Hardness (Pre-hardened) | 280-320 | HB |
~28-32 | HRC | |
Wytrzymałość na rozciąganie | 850 – 1300 | MPa |
Yield Strength | 770 – 1000 | MPa |
Elongation | 13 – 16 | % |
Impact Toughness | 20 – 42 | J/cm² |
Modulus of Elasticity | 205 – 212 x 10³ | MPa |
Przewodność cieplna | ||
* At 20°C | 29 – 35 | W/(m·K) |
* At 350°C | ~34 | W/(m·K) |
* At 700°C | ~33 | W/(m·K) |
Thermal Expansion Coeff. | ||
* 20-100°C | 11.2 – 12.0 x 10⁻⁶ | /K |
* 20-200°C | 12.8 x 10⁻⁶ | /K |
* 20-300°C | 13.5 x 10⁻⁶ | /K |
Critical Temperatures | °C | |
* Ac1 | 720 | °C |
* Ac3 | 800 | °C |
* Ms | 290 | °C |
Soft Annealing Temp. | 710-740 | °C |
Stress Relieving Temp. | 560-600 | °C |
Hardening Temperature | 840-880 | °C |
Tempering Temperature | 100-700 | °C |
P20+Ni steel benefits:
- Easy to machine, cuts production time.
- Polishes well, great for smooth finishes.
- Uniform hardness, durable for big molds.
- Tough, resists cracking under stress.
- Some corrosion resistance, pre-hardened, saves time.
P20+Ni equivalents DIN 1.2738
1.2738 steel is a German super pre-hardened plastic mold steel, supplied in a pre-hardened condition that eliminates the need for additional heat treatment and allows direct machining into molds. It offers excellent machinability, facilitates cutting and polishing, and undergoes stress-relief annealing and surface nitriding treatment with minimal dimensional and hardness changes. Particularly suitable for plastic mold frames with a thickness greater than 400mm.
1.2738 steel chemical composition
Węgiel (C) | Krzem (Si) | Mangan (Mn) | Fosfor (P) | Siarka (S) | Chrom (Cr) | Molybdenum (Mo) | Nickel (Ni) |
0.35 – 0.45 | 0.20 – 0.40 | 1.30 – 1.60 | ≤ 0.030 | ≤ 0.030 | 1.80 – 2.10 | 0.15 – 0.25 | 0.90 – 1.20 |
Physical Properties of 1.2738 Steel
Własność | Wartość | Unit |
Gęstość | 7.85 | g/cm³ |
Hardness (Pre-hardened) | 280-325 | HB |
Wytrzymałość na rozciąganie | 850 – 1100 | MPa |
Yield Strength | 770 – 980 | MPa |
Elongation | 13 – 16 | % |
Impact Toughness | 20 – 42 | J/cm² |
Modulus of Elasticity | 205 x 10³ | N/mm² |