Steel gradesAlloy and carbon...tool steel - 1.2...1.2738, AISI P20...

1.2738, 40CrMnNiMo8-6-4, AISI P20+Ni - plastic mould steel

1.2738, 40CrMnNiMo8-6-4, AISI P20+Ni, 40CMND8 - plastic mould steel, data according to ISO 4957:2001

Standard Grade
Chemical composition %
C: Si: Mn: P: S: Cr: Mo: Ni:
ISO 1.2738/40CrMnNiMo8-6-4
0.35 - 0.45 0.2 - 0.4 1.3- 1.6 <0.03 <0.03 1.8 - 2.1 0.15 - 0.25 0.9-1.2
GOST 40Ch2GNM - 40X2ГHM
0.35 - 0.45 0.2-0.4 1.3-1.6 <0.035 <0.035 1.8-2.1 0.15 - 0.25 0.9-1.2
ASTM AISI P20+Ni
0.4 - 1.5 - - 1.9 0.2 1.0
NF 40CMND8
0.4 0.3 1.5 <0.012 <0.005 1.9 0.2 1.0

1.2738, 40CrMnNiMo8-6-4, AISI P20+Ni, 40CMND8 – description

1.2738 is a plastic mould tool steel, used mainly for plastic injection die moulds. It can be viewed as enhanced version of 1.2311 alloy, with 1% nickel content having a positive effect on hardenability.

The steel is machinable, polishable, and suitable for texturing. Welding is somewhat difficult, but possible. Make sure to pre-heat and perform tempering, when the piece colled down after welding.

Physical and mechanical properties

1.2738 - general physical and mechanical properties in ambient temperature:

  • Linear expansion coefficient: 11.2 *10-6m/(m*K)
  • Thermal conductivity: 35 W/(m*K)
  • Hardness (in soft annealed condition): < 235 HB
  • Hardness (in hardened and tempered condition): < 51 HRC

Linear expansion coefficient of 1.2738 steel, in high temperature and in hardened and tempered condition:

  • Temperature range: 20-200 °C - 12.8 *10-6m/(m*K)
  • Temperature range: 20-300 °C - 13.5 *10-6m/(m*K)
  • Temperature range: 20-500 °C - 14.3 *10-6m/(m*K)
  • Temperature range: 20-700 °C - 14.9 *10-6m/(m*K)

Thermal conductivity of 1.2738 steel, in high temperature and in hardened and tempered condition:

  • Testing temperature: 350 °C - 34 W/(m*K)
  • Testing temperature: 700 °C - 33 W/(m*K)

Hardness of steel 1.2738 in hardened and tempered condition, at various tempering temperatures:

  • Tempering temperature: 100 °C - 51.5 HRC
  • Tempering temperature: 200 °C - 50.2 HRC
  • Tempering temperature: 300 °C - 48 HRC
  • Tempering temperature: 400 °C - 46.2 HRC
  • Tempering temperature: 500 °C - 43 HRC
  • Tempering temperature: 600 °C - 39 HRC
  • Tempering temperature: 700 °C - 29 HRC

Heat treatment and working

Recommended working and heat treatment parameters for 1.2738 alloy:

  • Forging: 1050-850 °C
  • Rolling: 1050-850 °C
  • Quenching: 840-870 °C
  • Soft annealing: 710-740 °C

We deliver this steel alloy as:

  • Forgings
  • Rods

Replacements, equivalents and other designations:

1.2738, 40CrMnNiMo8-6-4, AISI P20+Ni, 40CMND8, 40Ch2GNM, 40Х2ГНМ, M238

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