42CrMo Steel Bar

42CrMo steel (approximately US grade AISI-4140) belongs to low-alloy medium carbon steel and also belongs to ultra-high-strength steel.

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.

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

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%

Physical 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

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

Do You Wish To Know The Difference Between 42CrMo4 And 42CrMo?

The main difference is 42CrMo4 is EN standard, 42CrMo is China GB standard. P, V and S element is a little different each other, machinery property is similar.

42CrMo4 is from European standard-EN10083, 42CrMo4 is a kind of alloy steel with high hardenability, good toughness and small deformation during quenching. It has high creep strength and endurance strength at high temperature.

42CrMo is from China GB/T standard steel grade, it is a medium carbon alloy structural steel with good mechanical properties, good hardenability and wide application. In the machinery industry, it is often used to manufacture gears, connecting rods, high strength bolts and other important parts. China factory create 42CrMo follow SAE 4140 steel standard.The difference is below:

Based on the standard:

42CrMo4 is from EN10083 standard, which come from different standards, 42CrMo is from China GB/T 3077 alloy structural steel standard.

Chemical composition:

The chemical constituents of 42CrMo4 and 42CrMo are shown in Table 1 and Table 2.

Table 1:
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Table 2:
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