4340
4340 is a strong and ductile steel with both impact and shock resistance. When heat treated and hardened, 4340 demonstrates excellent tensile strength, toughness, and wear resistance.
4340 is used in the aerospace, automotive, and oil and gas drilling industries. Most commonly, it used for airplane landing gear, power transmission gears and shafts, and other structural parts.
4340 is great for high stress parts including piston pins, bearings, gears, axels, spindles, couplings, and dies.
Characteristics
Strong
Ductile
Impact and Wear Resistant
Properties when heat treated*
Yield Strength: 1545 MPa or 224.08 ksi
Tensile Strength: 12.93 GPa or 1875 ksi
Elongation: 12%
Applications
Bearings
Automotive Industry
Oil & Gas Industry
Additional information: 4340 is best machined when annealed or normalized and tempered. Welding hardened and tempered 4340 is not recommended and should be avoided. If welding, only do so in the annealed condition.
*Properties may vary based on heat treat and temper. Estimated properties are derived from a study of 4340 in last powder bed infusion in the Journal of Materials Engineering and Performance