4340 +QT Forged Alloy Steel Round Bar Finished Production
--- 4th.September.2023 ---
Sichuan Huitai produced 4340 Forged Steel Round Bar. Diameter 780mm x Length 2570mm,weight 9700Kg;Q+T(Quenching+Tempering)Delivery condition with hardness 30HRC.
4340 steel Equivalent Gardes:
Chinese GB steel grade: 40CrNi2MoA,
German DIN steel grade 36CrNiMo4,
German DIN material number 1.6511,
French NF standard 40NCD3,
Japanese JIS standard SNCM439,
British BS standard 816M40,
American AISI/ASTM 4340,
American UNS standard G43400
4340 Alloy Steel Chemical composition announcement
Carbon C: 0.38-0.43
Silicon Si: 0.15-0.35
Manganese Mn: 0.60-0.80
Sulfur S: ≤ 0.040
Phosphorus P: ≤ 0.035
Chromium Cr: 0.70~0.90
Molybdenum Mo: 0.20-0.30
Nickel: 1.65-2.00
Tensile strength σ B (MPa): ≥ 980 (100)
Yield strength σ S (MPa): ≥ 835 (85)
Elongation rate δ 5 (%): ≥ 12
Reduction of area ψ (%): ≥ 55
Impact energy Akv (J): ≥ 78
4340 Steel Characteristics
It has high strength, toughness, outstanding hardenability, and stability against overheating, but high sensitivity to white spots and temper brittleness. Poor weldability, requiring high-temperature preheating before welding, stress relief after welding, and use after tempering.
1.Mechanical properties:
Elongation rate δ 5 (%): ≥ 12
Reduction of area ψ (%): ≥ 55
Impact energy Akv (J): ≥ 78
Impact toughness value α KV (J/cm2): ≥ 98 (10)
Sample size: The size of the sample blank is 25mm
2.Heat Treatment
(Quenching 850 degrees; coolant: oil; tempering temperature 600 degrees; coolant: water, oil);
The Brinell hardness HBW of the steel in the annealed or high-temperature tempered supply state is less than or equal to 269;
3.Delivery Status
Delivery shall be made in a heat treated (normalized, annealed, or high-temperature tempered) or non heat treated state, and the delivery status shall be specified in the contract.
4340 steel Applications
Used as important quenched and tempered components that require good toughness, high strength, and large dimensions, such as heavy-duty machinery shafts, turbine shafts with a diameter greater than 250mm, helicopter rotor shafts, turbine shafts, blades, heavy-duty transmission components for turbojet engines, and crankshaft fasteners. Gears, etc; It can also be used to operate rotor shafts and blades with temperatures exceeding 400 ℃; After nitriding treatment, it can also be used to manufacture important parts with special performance requirements, and can be used as ultra-high strength steel after low-temperature tempering or isothermal quenching.
Usage
Manufacturing important components with high strength and good plasticity, and manufacturing important components with special functional requirements after nitriding treatment, such as shafts, gears, fasteners, etc.
