About Smiths Advanced

We are a leading stockholder and global supplier of metals and plastics into Aerospace & Space, Chemical, Defence, Medical, MRO, Naval, Nuclear, Oil & Gas and Power industries.

We make high quality materials available in a fast, cost-effective and convenient package and provide a consistent supply path for all our customers.

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4340 Steel Bar

Chromium-nickel-molybdenum alloy.


Our 4340 steel bars find use in the production of aircraft landing gear and bearing components.

Our range of 4340 deep-hardening steel bars offers excellent ductility with high strength.


4340 alloy finds use in deep-hardened constructional steel applications, particularly in the production of highly stressed parts. 4340 offers remarkable ductility and toughness and at a variety of strength levels and at elevated temperatures too. The alloy often finds use in engineering applications due to its strength and hardenability, which other carbon steel grades do not provide. With good fatigue strength, Alloy 4340 also resists embrittlement due to the materials excellent ductility. Machinability of the alloy is good using traditional methods, and fusion and resistance welding are possible.


Commercial Applications

Our 4340 steel bars find use in the production of aircraft landing gear, axles, spindles, bearing components and heavy-duty shafts. The product provides a superior combination of strength and malleability.



4340 Steel Bar Datasheet

Stock Availability

We stock 4340 steel bars in various sizes and conditions (including annealed, hardened, normalised and tempered conditions).



Product Features:


    AMS6414
    AMS6415
    AMS6484
    AMS-S-5000, MIL-S-5000
    ASTM A304
    ASTM A322
    BMS 7-28 (Boeing)
    UNS G43400

    Bearing components
    Axles
    Landing gear
    Heavy-duty shafts

    Excellent ductility
    High strength
    Good hardenability
    Virtually immune to embrittlement

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