42CrMo Steel Bar Introduce

 

42Cr2Mo steel is a super high strength steel with high strength and toughness, good hardenability, no obvious temper brittleness, small deformation during quenching, high fatigue limit and multiple impact resistance after quenching and tempering, good impact toughness at low temperature, high creep strength and endurance strength at high temperature. Surface hardening after quenching and tempering is usually used as heat treatment scheme for this steel. Suitable for manufacturing large and medium-sized plastic moulds requiring certain strength and toughness.


1. 42CrMo Equivalent World Steel Grade:

 

  • China Standard: GB/T 3077-1999
  • ISO Standard: 42CrMo4
  • CET Steel Standard: 42CrMo4
  • Japanese Standard: SCM440
  • German Standard: 42CrMo4 or 1.7225
  • American Standard: 4140 or G41400


2. Chemical composition:

 

  • Carbon C:  0.38-0.45%
  • Silicon Si:  0.17-0.37%
  • Mn: 0.50-0.80%
  • Sulfur S: < 0.035%
  • Phosphorus P:  < 0.035%
  • Chromium: 0.90-1.20%
  • Nickel:  < 0.030%
  • Copper: < 0.030%
  • Molybdenum: 0.15-0.25%

3. Physical properties:

 

  1. Critical point temperature (approximate value): Ac1 = 730 C, Ac3 = 800 C, Ms = 310 C.
  2. Linear expansion coefficient: temperature 20-100 degrees C/20-200 degrees C/20-300 degrees C/20-400 degrees C/20-500 degrees C/20-600 degrees C, linear expansion coefficient: 11.1 x 10K/12.1 x 10K/12.9 x 10K/13.5 x 10K/13.9 x 10K/13.9 x 10K 14.1 x 10K.
  3. Elastic modulus: temperature 20 degree C/300 degree C/400 degree C/500 degree C/600 degree C, elastic touch 210000MPa/185000MPa/175000MPa/165000MPa/15500oMPa
  4. 42CrMo allowable stress 42CrMo allowable stress 186-310/MPa, yield point 930s/MPa, 42CrMo strength, hardenability, good toughness, small deformation during quenching, high creep strength and endurance strength at high temperature.


3. Mechanical properties:

 

  • Tensile strength_b (MPa): > 1080 (110)
  • Yield strength_s (MPa): > 930 (95)
  • Elongation rate (%): > 12
  • Section shrinkage(%): > 45
  • Impact energy Akv (J): > 63
  • Impact toughness value alpha kV (J/cm2): > 78 (8)
  • Hardness: <217HB


4. Heat treatment:


Annealing annealing No.1 "annealing at 760 + 10 C, furnace cooling to 400 air cooling. HB220-230
Normalize No. 4 860 (+10 C) and discharge air-cooled.
Quenching quenching + tempering No. 5 840 (+10 (+10 (+10), (depending on the complexity of product shape), tempering 680-700 degrees. HB<217
Quenching at quenching + tempering No. 6 840 (+10) and tempering at 470. HRC41-45
Quenching at quenching + tempering No. 7 840 (+10) and tempering at 480. HRC35-45
Quenching at quenching + tempering No. 8 850 C and tempering at 510 degrees. HRC38-42
Quenching at quenching + tempering No. 9 850 C and tempering at 500 degrees. HRC40-43
Quenching at quenching + tempering No. 10 850 (?) and tempering at 510 (?) HRC36-42
Quenching at quenching + tempering No. 11 850 (?) and tempering at 560 (?) HRC32-36
Quenching at quenching + tempering No. 12 860 (?) and tempering at 390 (?) HRC48-52

 

5. MTC of 42CrMo and photos of 42CrMo:

 

 

 

 

The 42CrMo alloy steel material performance is very similar to 42CrMo4, but a little bit difference on chemical composition, mechanical properties, HT requirement, if you wish to know detailed difference please click URL below:

What is the difference of 42CrMo4 vs 42CrMo  

 

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