42CrMo? What material is 42CrMo steel?
42CrMo, an alloy steel. Belonging to ultra-high strength steel, it has high strength and toughness, good hardenability, no obvious temper brittleness, high fatigue limit and multiple impact resistance after quenching and tempering treatment, and good low-temperature impact toughness. This steel is suitable for manufacturing large and medium-sized plastic molds that require certain strength and toughness.
Chinese standard GB/T 3077-2015
Its corresponding * standard organization grade: 42CrMo4
Corresponding Japanese brand: SCM440
Corresponding German brand: 42CrMo4 or 1.7225
Approximate corresponding US brand: 4140 or G41400
42CrMo round steel
composition
Carbon C: 0.38-0.45%
Silicon Si: 0.17-0.37%
Manganese Mn: 0.50-0.80%
Sulfur S: allowable residual content ≤ 0.035%
Phosphorus P: allowable residual content ≤ 0.035%
Chromium Cr: 0.90-1.20%
Nickel Ni: allowable residual content ≤ 0.030%
Copper Cu: allowable residual content ≤ 0.030%
Molybdenum Mo: 0.15~0.25%
42CrMo is a special high steel grade that can be quenched and tempered. In the quenched and tempered state, it can provide a strong fusion of strength and toughness. Different European standards cover the specifications of this steel in different forms and processing conditions. Induction hardening can be applied to steel. This steel grade is usually provided in the form of a mixture of microstructure, namely martensite and austenite. Perform M treatment on the special grade of the steel to provide good cutting performance.
Allowable stress of 42CrMo
The allowable stress of 42CrMo is 186-310/MPa, with a yield point of 930 σ s/MPa. 42CrMo has high strength, hardenability, good toughness, small deformation during quenching, and high creep strength and endurance strength at high temperatures. 42CrMo is used to manufacture forgings with higher strength and larger quenched and tempered sections than 35CrMo steel, such as shafts, gears, connecting rods, transmission gears, turbocharger gears, engine cylinders, springs, spring clips, 1200-2000mm oil drill pipe joints, salvage tools, and to replace quenched and tempered steel with higher nickel content.
Tensile strength σ b (MPa): ≥ 1080 (110)
Yield strength σ s (MPa): ≥ 930 (95)
Elongation rate δ 5 (%): ≥ 12
Shrinkage rate of cross-section (%): ≥ 45
Impact energy Akv (J): ≥ 63
Impact toughness value α kv (J/cm2): ≥ 78 (8)
Hardness: ≤ 217HB
Sample size: The sample blank size is 25mm
42CrMo heat treatment
Annealing No.1: Annealing at 760 ± 10 ℃, furnace cooling to 400 ℃ and air cooling.
HB220-230
Normalize No.4 860 ± 10 ℃ and cool it out of the furnace.
Quenching and tempering No.5 840 ± 10 ℃ with water or oil (depending on the complexity of the product shape), and tempering at 680-700 degrees. HB<217
Quenching and tempering No.6 840 ± 10 ℃ quenching oil, followed by tempering treatment at 470 ℃. HRC41-45
Quenching and tempering No.7 840 ± 10 ℃ quenching oil, followed by tempering treatment at 480 degrees. HRC35-45
Quenching and tempering No.8 850 ℃ quenching oil, followed by tempering treatment at 510 ℃. HRC38-42
Quenching and tempering No.9: quenching oil at 850 ℃, followed by tempering treatment at 500 ℃. HRC40-43
Quenching and tempering No.10: oil quenching at 850 ℃, followed by tempering at 510 ℃. HRC36-42
Quenching and tempering No.11: Quenching oil at 850 ℃, followed by tempering treatment at 560 ℃. HRC32-36
Quenching and tempering No.12: oil quenching at 860 ℃, followed by tempering at 390 ℃. HRC48-52
Note: 1 Steel composition (%): 0.43 C, 0.88Mn, 1.09Cr, 0.22Mo, 1.017P, 0.027S;
2 . Steel composition (%): 0.39C, 1.11Cr, 0.20Mo;
3 . The horizontal impact value is indicated in parentheses.
process specification
Hot processing specifications
Heating temperature is 1150~1200 ° C, starting temperature is 1130~1180 ° C, ending temperature is>850 ° C, and when the diameter is>50mm, slow cooling is required.
Normalization standard
The normalizing temperature is 850~900 ° C, and it is air-cooled after being discharged from the furnace.
High temperature tempering specification
Tempering temperature is 680-700 ° C, and it is air cooled after being taken out of the furnace.
Quenching and tempering specifications
Preheating temperature 680~700 ° C, quenching temperature 840~880 ° C, oil cooling, tempering temperature 580 ° C, water cooling or oil cooling, hardness ≤ 217HBW.
Specification for strengthening and toughening treatment by sub temperature quenching
Quenching temperature 900 ° C, tempering temperature 560 ° C, hardness (37 ± 1) HRC
Induction hardening and tempering specifications
The quenching temperature is 900 ° C, the tempering temperature is 150-180 ° C, and the hardness is 54-60HRC.
Typical applications
1) Used for opaque forming molds such as bowls, dishes, clips (grocery products), etc.
2) Suitable for making large plastic molds.
3) Used for opaque molding molds (TV molds, air conditioning shell molds).
4) Used for automotive parts molds, commonly used resin products, fixtures, etc
5) Suitable for producing large and medium-sized molds that require certain strength and toughness.
For more questions about 42CrMo/4140/SCM440/1.7225 mold steel, you can also contact us through the following:
Email: info@saesteel.com
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