Alloy Bar 4340

4340 alloy steel bar is used heavily in the aerospace industry due to its ultra-high strength. When heat treated it is known for its toughness while preserving good fatigue strength. For highly stressed parts it is an excellent choice. It can be machined by all customary methods. This material is available in both vacuum melt (VM) and air melt (AM).

TGP available

We sell our trademark material Durelloy that is made to last and perform better than standard 4340.


  • Aircraft Landing Gear
  • Power Transmission Gears
  • Structural Use Applications

Typical Chemical Properties

Minimum Properties Tensile Strength, psi 140,000
Yield Strength, psi 120,000
Elongation 14%
Rockwell Hardness Rc 32/39
Chemistry Carbon(C) .38 -.43%
Chrome (Cr) 0.70- 0.90%
Manganese (Mn) 0.60-0.80%
Molybdenum (Mo) 0.20 – .30%
Nickel (Ni) 1.65-2.0%
Phosphorus (P) 0.030%
Sulphur (S) 0.040%
Silicon (Si) 0.15- 0.35%

Ameralloy Steel Corporation is a prime supplier of speciality steel bar products and wear-resistant high-impact steel plate. Our full catalogue features speciality steels and standard AISI alloys to meet your demanding applications.

Ameralloy’s precision-forged speciality steels and standard alloys are shipped worldwide with reliable on-time service.

Ameralloy provides engineering services for your steel products. From forging to machining and finishing, our Chicago based steel service centre will manufacture, ship, and deliver your order with unrivalled quality and service


Tap or Call: +1 (800) 237-0113

Email Project Specification: sales@ameralloy.com