4340 Round Bar | 4340 Tubing

Shapes Available

  • Flat
  • Plate
  • Round Bar
  • Square Bar
  • Tubing


  • Aerospace
  • Manufacturing

Industry Names

  • 4340 AQ
  • E4340
  • 300M
  • Alloy 4340
  • Aircraft Quality 4340
  • 4340 VAR


  • Cold Finished and Alloy


  • AMS 2301
  • AMS 6359 (Plate)
  • AMS 6414 (Round Bar)
  • AMS 6415 (Round Bar)
  • UNS G43400


  • Aircraft Landing Gear
  • Power Transmission Gears and Shafts
  • Structural Parts


  • Good Toughness
  • High Strength in the Heat Treated Condition

4340 steel is a low alloy steel that contains Nickel, Chromium and Molybdenum as strengthening agents. 4340 can also be hardened through heat treatment. Flame and induction hardening is the type of heat treatment that works with 4340. 4340 offers better hardenability and improved impact toughness over 4140.

Alloy 4340 can obtain deep hardenability. This is important when higher strength is needed in heavy sections. Thus 4340 assures maximum toughness as well as ductility at a given strength level. Have high stressed parts? 4340 is perfect because it maintains its properties at high temps.

4340 can be machined in either annealed or normalized and tempered conditions through most all conventional machining techniques. 4340 is available in Round Bar, Plate, and Tubing. For more info on aircraft alloys, check out this YouTube video we made! Or watch the newest video  we recently made on JUST 4340 below:

Please contact us to request a quote. We specialize in hard to find material.

We work closely with many manufacturers in the aerospace & defense industry. We work with NADCAP approved heat treaters and testing laboratories. We can supply DFARS compliant material.

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