P20+Ni Tool Steel – Frequently Asked Questions
P20+Ni (DIN 1.2738) is a nickel-modified pre-hardened plastic mold steel supplied ready-to-use at 28–34 HRC. No heat treatment is needed after delivery.
It contains 0.33–0.43% C, 1.80–2.10% Cr, 0.30–0.55% Mo, 0.85–1.15% Ni, 0.60–0.90% Mn, and 0.20–0.40% Si.
Nickel improves through-hardening in large mold blocks, ensuring uniform hardness even in sections exceeding 400 mm. It also improves toughness and impact resistance.
Pre-hardened to 28–34 HRC (290–330 HB), tensile strength approximately 965–1100 MPa, good toughness with CVN impact of 30–50 J, and density of 7.85 g/cm³.
It is widely used for large plastic injection mold cavities and cores, blow molds, compression molds, and automotive or appliance molds where block thickness exceeds 300–400 mm.
No. It is supplied pre-hardened and can be machined directly to final dimensions. This eliminates distortion risk and saves production time, which is its biggest advantage.
Suitable for ABS, PP, PE, PS, PC, PA, and TPU. Not recommended for abrasive filled plastics or corrosive resins like PVC — use S136 or 420SS for those.
Good weldability compared to harder mold steels. Preheat to 250–300°C, use matching P20-type filler wire, and stress-relieve at 580–620°C after large repairs
P20+Ni has 0.85–1.15% nickel that standard P20 (1.2311) lacks. This gives better through-hardening and toughness for large blocks. For blocks under 300 mm, standard P20 is usually sufficient.
Nitriding (surface hardness up to 65–70 HRC), hard chrome plating, PVD coatings (TiN, CrN), and electroless nickel plating are commonly used to improve wear and corrosion resistance.
