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ExEll™ P20M-High Hard

Download ExEll™ P20M-High Hard Spec sheet

P20M High Hard is a higher hardness version (BHN 311-352) of this alloy. The higher hardness level offers greater mold tool wear resistance to abrasive plastic compounds as well as better surface polishing capability.


Typical C Mn Si Cr Mo
Analysis % .34 .80 .40 1.75 .40


  • P-20 High Hard is a pre-hardened mold steel that has been specially designed for large plastic molds.
  • Material is forged on a 5000 ton press assuring maximum deformation during the forging process.
  • Supplied hardness of 321—352 HB (34-38 HRC).
  • Hardness loss in large cross sections is minimal.


  • Improved polishability compared to P-20 modified
  • Excellent compressive strength
  • Minimal hardness loss in large cross sections


  • Injection molds
  • Compression molds
  • Mold frames
  • Forming tools
  • Die holders


Density: 0.284 lbs/in3 (room temperature)

Coefficient of Thermal Expansion P20-High-Hard_08 P20-High-Hard_03 P20-High-Hard_05
Thermal Conductivity P20-High-Hard_13 P20-High-Hard_15 P20-High-Hard_17


Room Temperature, hardened and tempered to 321 BHN (34 HRC)

Yield Strength Tensile Strength Elongation Reduction Area
130 KSI 150 KSI 15% 35%


P-20 High Hard can yield an A-2 surface finish when proper polishing procedures are followed. Caution must be taken to avoid over polishing which lead to orange peel effect and pitting.


Stress Relieving

Temperature Cooling Note
Hold 1 hour/inch
Air Cool Large cross sections require accurate control of temperatures and times.


  • Heat uniformly and thoroughly at the selected temperature and hold at temperature for one hour per inch of total thickness.

Temperature °F 700 800 900 1000 1050 1100 1150
Hardness HRC 51 50 47 43 40 35 33
  • Tempering harness is approximate and based on two hours at temperature


  • Preheat insert to 600°F to 700°F. Maintain temperature above 600°F during welding.
  • Use TIG with D.C. positive polarity.
  • Depending on the application, various welding rods can be used. P-20 filler which will match the hardness of the base metal after welding and tempering is commonly used. Please contact our heat treatment facility for recommendations.
  • Slowly cool sown to 100°F—150°F, preferably under an insulating blanket, before post heat.
  • Post heat at 1000°F one hour per inch of weld depth plus one additional hour—double temper if possible. Exceeding 1050°F could result in the loss of hardness.

Electrode Dia. (mm) Filler Rod Dia. (mm) Welding AMPS Argon Flow Lt/min Nozzle Dia. (mm)
1.0 1.0 15-80 4-8 8
1.6 1.6 70-150 6-9 8-10
2.4 2.4 100-250 7-10 8-10
3.2 3.2 250-400 10-15 8-10


All statements regarding the properties or utilization of the materials or products mentioned are for the purposes of description only. Guarantees regarding the existence of certain properties or a certain utilization are only valid if agreed upon in writing.

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