AISI 4140 steel plate

Product Application: Mechanical high-strength gears, crankshafts, transmission shafts, oil drill pipe joints, deep well tools, automotive engine connecting rods, suspension parts, aircraft landing gear structural parts, fasteners, cold work molds, wear-resistant tools, etc

Delivery conditions:The goods can be delivered under various conditions, such as hot rolling, normalization, tempering, quenching, N+T, T+Q, etc. Z15-Z35 can also be provided.

Specifications & Standards:Refer to the table below

Consultation Hotline: 0086-371-55023661

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CategoryDetails
Executive StandardsASTM A29/A29M, EN 10083-13
GradesAISI 4140, 42CrMo4, JIS SCM440, GB/T 3077 42CrMo
Product Form & Dimensions Thickness: 8mm – 150mm
Width: 1000mm – 4000mm
Length: 1000mm – 20000mm
Chemical Composition (%) (Melting Analysis)C: 0.38 – 0.43Si: 0.15 – 0.35Mn: 0.75 – 1.00P ≤ 0.035, S ≤ 0.040 (per ASTM Standard)Cr: 0.80 – 1.10Mo: 0.15 – 0.25Ni ≤ 0.30, Cu ≤ 0.30 (supplementary per GB Standard)
Mechanical Properties (Quenched & Tempered State)Tensile Strength: 980 – 1130 MPa
Yield Strength: ≥ 930 MPa
Elongation (A5): ≥ 12%- Reduction of Area: ≥ 45%
Impact Energy (-20℃): ≥ 63 J (transverse Charpy V-notch)
Hardness: 241 – 285 HB (annealed); 28 – 34 HRC (quenched & tempered)
Heat Treatment ProcessQuenching: 850℃ oil cooling- Tempering: 540 – 650℃ air cooling (adjusted by hardness requirements)
Normalizing: 860℃ air cooling (grain refinement)
Surface Treatment: Nitriding (hardness up to HV900)
Physical PropertiesDensity: 7.85 g/cm³- Elastic Modulus: 190 – 210 GPa
Coefficient of Thermal Expansion: 12.2×10⁻⁶/℃ (20 – 100℃)
Melting Point: 1416℃
Processing TechnologyWelding: Preheating to 200 – 300℃ required, use low-hydrogen electrodes, post-weld tempering for stress relief
Machinability: Good in annealed state (65% machinability compared to AISI 1212 steel)
Cold Forming: Perform after annealing to avoid cracking
Application FieldsMachinery Manufacturing: High-strength gears, crankshafts, transmission shafts
Energy Equipment: Oil drill pipe joints, deep well tools (withstand high pressure below 2000m)
Automotive Industry: Engine connecting rods, suspension components
Aerospace: Landing gear structural parts, fasteners
Mold Manufacturing: Cold working molds, wear-resistant tools (service life increased by 3-5 times after nitriding)
Inspection RequirementsTensile test, impact test, hardness test- Ultrasonic flaw detection (ASTM E2375/SAE AMS 2154, 100% coverage)
Provide EN 10204 3.1/3.2 material certificate
Special CharacteristicsHardenability: Critical oil quenching diameter about 30mm, uniform properties achievable via quenching and tempering for large-section parts
Fatigue Resistance: High purity (P ≤ 0.035%, S ≤ 0.040%) ensures low notch sensitivity
High-Temperature Stability: Maintains high strength below 427℃, suitable for turbo-machinery components

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