4340

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.