
Product Information
Product ID: Supplying USA 4340 Alloy Steel, 4340 Round Steel, 4340 Round Bar, Reasonable 4340 Price, Quality Guaranteed
Standard: ASTM A29/A29M-04
Chemical Composition:
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 (Ni): 1.65~2.00
Product Application:
Used for critical quenched and tempered parts with high toughness and strength, and large dimensions, such as heavy machinery's high-load shafts, shafts for machinery wheels with diameters over 250mm, helicopter rotor shafts, turbine jet engine turbine shafts, blades, high-load transmission parts, crankshaft fasteners, and gears; also suitable for rotor shafts and blades operating at temperatures above 400℃; and can be nitrided for the production of critical parts with special performance requirements, which can be used as ultra-high strength steel after low-temperature tempering or isothermal quenching.
Processing Technology: Hot Rolling, Cold Drawing
Theoretical Weight Chart (Unit: kg/m², mm): 7.85 T/㎡
Characteristics: High strength, toughness, quenching permeability, and stability against overheating, but high sensitivity to white spots and temper embrittlement. Poor weldability; requires preheating at high temperatures before welding and stress relief after welding. Use after heat treatment.
Mechanical Properties:
Tensile elongation δ5 (%): ≥12
Section reduction rate ψ (%): ≥55
Impact Energy Akv (J): ≥78
Impact toughness value αkv (J/cm2): ≥98(10)
Sample Size: Rough Sample Dimensions of 25mm
Heat Treatment:
(Quenching at 850 degrees; coolant: oil; tempering temperature 600 degrees; coolants: water, oil)
Steel supply condition for annealing or high-temperature tempering, with Brinell hardness GBW not exceeding 269.
● Delivery Condition: Shipped either in heat treated (normalizing, annealing, or high-temperature tempering) or non-heat treated condition; the delivery condition should be specified in the contract.






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