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P-20 HI HARD Plastic Mold Alloy Steel

P-20 HI HARD is mold quality alloy steel supplied in the prehardened condition. Special melting and refining practices are utilized to produce a uniform product with exceptional cleanliness. These characteristics allow P-20 HI HARD to be polished to an extremely high finish required for plastic molding. The material is tested to rigorous tool steel standards to ensure uniformity of structure and freedom from defects. P-20 HI HARD is supplied prehardened to 352/461 BHN. The balanced alloy composition of P-20 HI HARD ensures a uniform cross-sectional hardnes.












0.28 – 0.401.40 – 2.000.60 – 1.000.30 – 0.550.03 Max.0.03 Max.0.20 – 0.80

Size Availability:

Flats • Hollowbar • Metric • Non-Standard • Rounds • Squares • Standard


AISI P20 Alloy Steel-US
AISI P20 Mold Steel-US
DIN 1.2330-Germany
UNS T51620-US

TreatmentTemperature RangeCooling/QuenchingNotes
Stress Relieving800-900° FAir cool or furnace cool to room temperatureHeat slowly and uniformly.
Annealing1500-1600° FCool slowly 50° F per hour max to 1200° F and air cool.It is recommended that P-20 HI HARD be annealed prior to rehardening. Heat slowly to 1500-1600° F for four hours.
Hardening1550-1600° FOil quench to 150° F or hand warm and temper immediately.P-20 HI HARD is normally used in the pre-hardened condition, but may be heat-treated to higher hardness levels for higher strength or for lens mold applications. Preheat and then heat to 1550-1600° F and soak one half hour when material is up to temperature.
Preheating1250° FPreheat to 1250° F and hold one hour.
Tempering(See Chart)Temper one hour per inch of section thickness to desired hardness.
Data is typical and should not be construed as actual values for any category.
Applications and technical information require engineers and tool designers to exercise independent judgement.

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