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4340 Alloy Steel

An Iron-based alloy steel, 4340 contains Nickel, Chromium and Molybdenum

4340 Alloy Steel can be heat treated to achieve high strength whilst maintaining good toughness, wear resistance and fatigue strength levels, combined with strength up to 315 ºC.


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4340 Round bar30 mm160 mm GET A QUOTE

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Perfect for applications in the Aerospace industry

4340 Alloy Steel can be used in a variety of applications, here are just a few examples:

  • Commercial and military aircraft
  • Automotive systems
  • Forged hydraulic systems

About 4340 Alloy Steel

4340 Alloy Steel is an Iron-based alloy containing Nickel, Chromium and Molybdenum. The relatively high Carbon content provides this alloy with superior strength in applications where severe service conditions exist.

4340 Alloy Steel has high strength, superior toughness and good ductility. In addition, the alloy is immune to embrittlement.


To learn more about 4340 Alloy Steel contact us today, or fill in our online quote form and we’ll get right back to you!


7.85 g/cm^3
Melting Range:
Specific Heat Capacity:
448 J/kg*K
Electrical Resistivity:
1.09 µΩ.m
Coefficient of Thermal Expansion from -18-93°C:
11.3 µm/mm/°C
Coefficient of Thermal Expansion from -18-649°C:
14.6 µm/mm/°C


AMS 6409, 6415, 2304
Download the 4340 Alloy Steel Data Sheet Download

FAQs & Resources

An iron –based alloy containing Nickel Chromium and Molybdenum combined with high carbon content.

Excellent strength, which is required in severe service conditions. This is coupled with toughness and good ductility make the alloy immune to embrittlement.

Embrittlement is the loss of ductility making the material subject to cracking. In addition, low ductility makes the alloy very difficult to form without cracking.

Forged hydraulic systems used in commercial and military aircraft and high performance automotive systems.

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Fill in our online form to get a fast quote. Got a technical question? Contact us on techsales@neonickel.com or for more general enquiries please email us at enquiries@neonickel.com