Introduction of AISI 4340 steel properties

     AISI 4340 steel is one of the alloy structural steel , also known as alloy steel. It is based on high quality carbon structure steel, properly adding one or several kinds of alloy elements (the total content of not more than 5%) steel made. The AISI 4340 steel properties with high strength, high toughness and excellent hardenability and anti overheating stability, but white has high sensitivity, temper brittleness. Poor weldability, prior to welding need to high temperature preheating, after soldering need to eliminate stress, after adjustment use.
     Mechanical properties of AISI 4340 steel is as follows:
     Tensile strength σb (MPa): ≥980 (100)
     Yield strength σs (MPa): ≥835 (85)
     Elongation δ5 (%): ≥12
     Reduction of area ψ (%): ≥55
     Impact energy Akv (J): ≥78
     Impact toughness αkv (J / cm & sup2;): ≥98 (10)
     Sample size: Sample size is 25mm rough
     Heat treatment: (Quenching temperature: 850 degrees; coolant: oil; tempering temperature: 600 degrees; Coolant: water, oil);
     Steel annealing or tempering condition Brinell hardness GBW≤269
     According to AISI 4340 steel properties, which can be used to make good toughness, high strength, as well as an important regulator of large-size parts, such as heavy machinery and high load shaft. The size of machine shaft large than 250mm in diameter. Helicopter rotor shaft. Turbojet turbine shafts, blades, high load transmission parts. Crankshaft fasteners. And other gear. Can also be used to operate the temperature exceeds 400 ℃ rotor shaft and blades; AISI 4340 steel can also be nitriding treatment, used to manufacture special performance requirements of the important parts, such as shafts, gears, and other fasteners. After quenching or after isothermal tempering can be used for ultra-high-strength steel.

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