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4340 Round Bar | 4340 Tubing

Shapes Available

  • Plate
  • Round 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.

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.

DISCLAIMER: The information provided on this Web site, technical or otherwise, is merely for informational purposes, and is not intended to serve as a guide, manual, instructions, or any kind reference for proper safety procedures or material purchasing. Michlin Metals makes no warranty, express or implied, based on the statements on this Web site and, as such, will not be liable for any damages, either direct or indirect, including but not limited to consequential damages, such as damages for loss of profits, that may arise based on reliance on the information provided on this Web site. Some information has been referenced from reliable industry sources. Tradenames listed are the sole property of the tradename owners. Michlin Metals typically provides branded products through its relationships with mills and authorized re-sellers. Equivalent non-branded product is sometimes also available through certified sources of such products. Michlin Metals will never substitute non-branded product when branded product is requested.

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