4140 Annealed - Aircraft Alloy - Fry Steel

Aircraft Alloys / 4140 ANN

4140 annealed is an aircraft quality low-alloy steel containing chromium, molybdenum, and manganese. The chromium content provides good hardness penetration, and the molybdenum imparts uniform hardness and high strength. 4140 in the annealed condition provides good ductility before being hardened to a capability of 50 HRC. This alloy is characterized by its high fatigue strength, torsional strength, abrasion resistance, and toughness. This material is used to produce piston rods, shafts, crank shafts, gears and other machinery parts. (UNS G41400)

Chemical Makeup of Alloy 4140 Steel

Element Min Max
Carbon, C 0.38 0.43
Manganese, Mn 0.75 1
Silicon, Si 0.15 0.35
Phosphorus, P - 0.025
Sulfur, S - 0.025
Chromium, Cr 0.8 1.1
Molybdenum, Mo 0.15 0.25
Nickel, Ni - 0.25
Copper, Cu - 0.25
Aluminum, Al 0.02 0.05
Vanadium, V 0.02 0.08
Columbium/Niobium, Nb 0.02 0.05

Common Applications of Alloy 4140 Steel

  • Aerospace Aerospace
  • Industrial Industrial

Benefits

  • Superior Toughness
  • Good Ductility
  • Good Wear Resistance

We stock 4140 ANN to the following specifications:

  • AMS-2301
  • AMS-2304
  • AMS-6349 EXC. COND.
  • AMS-6382
  • AMS-S-5626
  • ASTM-A-331
  • MIL-S-5626

Click on a cross-section to see the sizes we stock:

Subscribe now!

Stay up to date with the latest on Fry Steel and industry news.