CNC Machining 4140 Steel Parts
4140 Steel Has High Strength, Excellent Hardenability, Good Toughness, Small Deformation During Quenching, High Creep Strength And Long-Lasting Strength At High Temperatures.
It Is Used In The Manufacture Of Forgings That Require Higher Strength And Larger Quenched Sections Than 35CrMo Steel.
Chinese Name: 4140 Alloy Structural Steel
Type: Alloy Structural Steel
Executive Standard: ASTM A29/A29M-04
Features: Good Processability
Characteristic:
4140 Steel Has Good Processability, Small Processing Deformation, And Good Fatigue Resistance. It Is Medium Hardenability Steel.
4140 Has Good Strength And Good Comprehensive Mechanical Properties After Heat Treatment, Good Manufacturability And High Yield.
The Maximum Operating Temperature Is 427 Degrees Celsius. 4140 Strength, High Hardenability, Good Toughness, Small Deformation During Quenching, High Creep Strength And Long-Lasting Strength At High Temperatures.
Use
Forgings Requiring Higher Strength And Larger Quenching Section Than 35CrMo Steel, Such As Large Gears For Locomotive Traction, Supercharger Transmission Gears, Rear Axles, Extremely Loaded Connecting Rods And Spring Clips, Can Also Be Used Oil Deep Well Drill Pipe Joints And Fishing Tools Below 2000m, And Can Be Used For Molds Of Bending Machines, Etc.
Chemical Composition:
Region: China
Standard: GB/T 3077-1999
C: 0.38～0.45
Si: 0.17～0.37
Mn: 0.50～0.80
P: ≤0.035
S: ≤0.035
Cr: 0.9～1.20
Ni: ≤0.30
Mo: 0.15～0.25
Cu: ≤0.30
Mechanical Properties:
Tensile Strength σb (MPa): ≥ 1080 (110)
Yield Strength σs (MPa): ≥ 930 (95)
Elongation δ5 (%): ≥12
Area Shrinkage ψ (%): ≥ 45
Impact Work Akv (J): ≥ 63
Impact Toughness Value αkv (J/cm2): ≥78(8)
Hardness: ≤217hb
Sample Size: Sample Blank Size Is 25mm
Steel Mill Specifications:
| Product Name | Specifications / Mm | Material |
| Wire | Ф5.5-30 | 4140 |
| Hot Rolled Round Steel | Ф3.0-100 | 4140 |
| Hot Rolled Round Steel | Ф100-200 | 4140 |
| Hot Rolled Round Steel | Ф100-400 | 4140 |
| Hot Rolled Steel Sheet | 1-100 | 4140 |
| Hot Rolled Round Steel | Ф200-400 | 4140 |
Heat treatment process:
Annealing No.1 “Annealed at 760±10°C, air cooled to 400°C. HB220-230
Normalize No.4 860±10°C normalizing, air-cooled.
Quenching+tempering No.5 840±10°C quenching or oil (depending on the complexity of the product), tempering at 680-700 degrees.HB<217
Quenching+tempering No.6 840±10°C quenching oil, then tempering at 470 degrees.HRC41-45
Quenching+tempering No.7 840±10°C hardened and tempered at 480 degrees.HRC35-45
Quenching+tempering No.8 850 °C hardened, and then tempered 510 degrees.HRC38-42
Quenching+tempering No.9 850 °C hardened, and then tempered 500 degrees.HRC40-43
Quenching+tempering No.10 850 °C hardened, and then tempered at 510 °C.HRC36-42
Quenching+tempering No.11 850 °C hardened, and then tempered at 560 °C.HRC32-36
Quenching+tempering No.12 860 °C hardened, and then tempered at 390 degrees.HRC48-52
Its Corresponding International Standard Organization Number: 42CrMo4
Japanese Brand: SCM440
German Brand: 42CrMo4
US Brand: 4140
British BS 708M40/708A42/709M40
French NF 40CD4/42CD4
China GB 42CrMo
Russian ГOCT 38XM
Steel Calculation Formula:
Square Tube: (Length + Width) × Thickness × 2 × 0.00785
Cold Plate: (Length × Width) × Thickness × 0.00785
Hot Plate: (Length × Width) × Thickness × 0.00785
Welded Pipe: (Outer Diameter – Wall Thickness) × Wall Thickness × Length × 0.02466
Flat Steel: (Length × Width) × 0.00785
Round Steel: (Diameter × Diameter) × 0.00617
Square Steel: (Length × Width) × 0.00785
Galvanized Pipe: (Outer Diameter – Wall Thickness) × Wall Thickness × Length × 0.02466 × 1.06
Medium Plate: (Length × Width) × Thickness × 0.00785
Galvanized Sheet: (Length × Width) × Thickness × 0.00785 × 1.06
Seamless Tube: (Outer Diameter – Wall Thickness) × Wall Thickness × Length × 0.02466