P20 Steel Grade 1.2738H.H. Round

Product Description

• Material Description:

  • P20 High Hard (1.2738H.H.) is an improved pre-hardened mold steel specifically designed for large plastic molds.
  • It undergoes forging on a 5000-ton press, ensuring maximum deformation during the forging process.
  • Supplied hardness ranges from 321 to 352 HB (34-38 HRC), with minimal hardness loss in large cross sections.

• Characteristics:

  • Homogeneous Strength: Suitable even for large dimensions.
  • Applications:
    • Big cavity plates with deep cavities.
    • Highly stressed core components.

• Heat Treatment:

  • Stress Relieving Temperature: 850F - 900F (Hold 1 hour per inch; air cool).
  • Tempering: Heat uniformly and thoroughly at the selected temperature, holding for one hour per inch of total thickness.

• Physical Properties:

  • Density: Approximately 0.284 lbs/in at room temperature.
  • Coefficient of Thermal Expansion:
    • 700F 2000F: 6.8 x 10/F
    • 700F 4000F: 7.0 x 10/F
    • 700F 5750F: 7.1 x 10/F
  • Thermal Conductivity:
    • 700F: 202 Btu/in/ft/hr/F
    • 4000F: 209 Btu/in/ft/hr/F
    • 8000F: 216 Btu/in/ft/hr/F

• Mechanical Properties (Room Temperature, hardened and tempered to 321 BHN):

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

• Welding:

  • Preheat insert to 900F 1000F and maintain temperature above 800F during welding.
  • Use TIG with D.C. positive polarity.
  • Slowly cool down to 350F before post-heat treatment.

• Polishing:

  • Can achieve an A-2 surface finish with proper procedures.
  • Caution to avoid over-polishing (orange peel effect and pitting).