Steel P20+Ni · hardness band
Steel P20+Ni Prehard-HH
Properties of the Prehard-HH condition, compared with the other P20+Ni tempers.
Pick the high-hardness pre-hardened grade at 36–40 HRC (340–380 HB), offered as 1.2738HH/TS, for medium and large molds needing more wear resistance yet still no heat treatment.
What is P20+Ni Prehard-HH?
P20+Ni Prehard-HH is P20+Ni heat treated to Prehard-HH — pick the high-hardness pre-hardened grade at 36–40 HRC (340–380 HB), offered as 1.2738HH/TS, for medium and large molds needing more wear resistance yet still no heat treatment. P20+Ni Prehard-HH has a yield strength of 1,050 MPa (152 ksi) and a tensile strength of 1,230 MPa (178 ksi) — stronger than 93% of steel grades. Elongation at break is 12% and the elastic modulus is 210 GPa (30.5 Msi). P20+Ni Prehard-HH has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,420°C (2,588 °F). Annealed is the default condition FabDigit quotes; Prehard-HH is available on request or by drawing note.
Advantages
- Polishes to a fine finish — 85/100, better than 99% of steel grades
- High strength — 1,050 MPa (152 ksi), better than 93% of steel grades
Limitations
- Limited ductility — 12%, worse than 84% of steel grades
- Poor heat conductor — 34 W/m·K (19.6 BTU/hr·ft·°F), worse than 77% of steel grades
P20+Ni Prehard-HH properties
Typical room-temperature values for P20+Ni Prehard-HH — 11 properties are specific to this condition; the rest are grade-level values shared by every P20+Ni temper. Each bar shows where the value sits among the steel grades in FabDigit's library — further right is higher.
Physical3
P20+Ni Prehard-HH has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,420°C (2,588 °F).
Mechanical17
P20+Ni Prehard-HH has a yield strength of 1,050 MPa (152 ksi) and a tensile strength of 1,230 MPa (178 ksi) — stronger than 93% of steel grades. Elongation at break is 12% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
P20+Ni Prehard-HH is rated for continuous service to 400°C (752 °F). It conducts heat at 34 W/m·K (19.6 BTU/hr·ft·°F), worse than 77% of steel grades. Thermal expansion is 12.3 µm/m·K (6.83 µin/in·°F).
Electrical2
P20+Ni Prehard-HH has an electrical resistivity of 2.4×10⁻⁷ Ω·m.
Chemical & Environmental3
Corrosion resistance is poor (15/100), better than 75% of steel grades.
Sustainability4
Producing a kilogram of P20+Ni Prehard-HH takes about 30 MJ of energy and emits 2.2 kg of CO₂ — more than 55% of steel grades. Typical recycled content is 30%.
Manufacturability6
P20+Ni Prehard-HH's machinability is fair (42/100, worse than 72% of steel grades); weldability fair (50/100); formability poor (30/100).
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other P20+Ni tempers and conditions
P20+Ni is also supplied in 4 other conditions. The full side-by-side table is on the P20+Ni overview.
- AnnealedDefaultPick the softened ≤235 HB delivery state when you will quench and temper in house or must remove heavy stock by rough machining or cold piercing.430 MPa yield · 210 HB
- Q&TChoose oil or air quenching from 840–870 °C plus tempering to 40–50 HRC for small inserts and slides needing more than pre-hardened hardness; leave stock for quench distortion.1,250 MPa yield · 45 HRC
- Prehard-HHPick the high-hardness pre-hardened grade at 36–40 HRC (340–380 HB), offered as 1.2738HH/TS, for medium and large molds needing more wear resistance yet still no heat treatment.1,050 MPa yield · 38 HRC
- NitridedSpecify gas or plasma nitriding over the pre-hardened core for a 600–700 HV surface when molding glass- or mineral-filled plastics; cavity wear and scratch resistance rise, core toughness is kept.1,000 MPa tensile
- PrehardUse the pre-hardened and tempered 28–34 HRC (285–330 HB) supply state to rough and finish-mill cavities straight into production, with no later heat treatment and no distortion risk.860 MPa yield · 31 HRC
Working with P20+Ni Prehard-HH
Is P20+Ni easy to machine?
At the prehardened 30 HRC level it can be milled directly with coated carbide, positive-rake geometry and ample coolant; stress-relieve large blocks at about 550 °C before deep cavity cutting to limit distortion.
Can P20+Ni be welded?
Repair welding requires 300–350 °C preheat with interpass temperature held, matched P20/1.2738 filler, and stress-relief tempering at about 500–550 °C immediately after welding.
Can P20+Ni be formed, bent or molded?
Not a cold-forming material; hot work between 1050 and 850 °C, then slow cool and anneal. Finished geometry is produced by cutting and EDM.
What surface finishes work on P20+Ni?
Polishes to A2/B1 mirror level, with ESR material giving the best results; nitriding, hard chrome or electroless nickel add wear and rust protection, and blasted or etched textures reproduce consistently.
P20+Ni chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| CDIN 40CrMnNiMo8-6-4 | 0.35 – 0.45 | 0.4 |
| Si | 0.2 – 0.4 | 0.3 |
| Mn | 1.3 – 1.6 | 1.45 |
| P | ≤ 0.03 | — |
| Smax; mirror-finish grade requires ≤ 0.005 | ≤ 0.03 | — |
| Cr | 1.8 – 2.1 | 1.95 |
| Mo | 0.15 – 0.25 | 0.2 |
| Niadded versus P20; increases hardenability | 0.9 – 1.2 | 1.05 |
| Fe | balance | — |
P20+Ni Prehard-HH — frequently asked
What is P20+Ni Prehard-HH used for?
P20+Ni Prehard-HH is typically used for large injection mould cavities and cores, mould inserts, mould plates and bolsters, blow mould bodies, die-cast machine mould frames and textured cosmetic mould surfaces. In short: nickel-modified mold plate.
What is the yield strength of P20+Ni Prehard-HH?
P20+Ni Prehard-HH has a typical yield strength of 1,050 MPa (152 ksi) and a tensile strength of 1,230 MPa (178 ksi) — stronger than 93% of steel grades. Strength varies by condition: see the 5 listed tempers.
Is P20+Ni Prehard-HH easy to machine?
Not especially — machinability is rated fair (42/100, worse than 72% of steel grades). At the prehardened 30 HRC level it can be milled directly with coated carbide, positive-rake geometry and ample coolant; stress-relieve large blocks at about 550 °C before deep cavity cutting to limit distortion.
Can P20+Ni Prehard-HH be welded?
With care — weldability is rated fair (50/100). Repair welding requires 300–350 °C preheat with interpass temperature held, matched P20/1.2738 filler, and stress-relief tempering at about 500–550 °C immediately after welding.
What surface finishes work on P20+Ni Prehard-HH?
Polishes to A2/B1 mirror level, with ESR material giving the best results; nitriding, hard chrome or electroless nickel add wear and rust protection, and blasted or etched textures reproduce consistently.
Can P20+Ni Prehard-HH be formed, bent or molded?
Not a cold-forming material; hot work between 1050 and 850 °C, then slow cool and anneal. Finished geometry is produced by cutting and EDM.
What is the maximum service temperature of P20+Ni Prehard-HH?
P20+Ni Prehard-HH is rated for continuous use to about 400°C (752 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between P20+Ni Annealed and P20+Ni Prehard?
Annealed is the default condition — pick the softened ≤235 HB delivery state when you will quench and temper in house or must remove heavy stock by rough machining or cold piercing. Prehard: use the pre-hardened and tempered 28–34 HRC (285–330 HB) supply state to rough and finish-mill cavities straight into production, with no later heat treatment and no distortion risk. Yield strength is 430 MPa in Annealed versus 860 MPa in Prehard.
Can FabDigit make parts in P20+Ni Prehard-HH?
Yes — P20+Ni Prehard-HH is available for CNC machining with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- DIN EN ISO 4957 Tool steels (40CrMnNiMo8-6-4 / 1.2738) — DIN/ISO (2018)
- GB/T 1299 3Cr2MnNiMo — SAC (2014)
- Prehardened plastic mould steel 1.2738 / 718 datasheet — Assab / voestalpine BÖHLER, Buderus Edelstahl (2022)
- ASM Handbook Vol.1 Properties and Selection: Irons, Steels — ASM International (1990)
- Tool Steels, 5th ed. — ASM International (1998)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.