4130 (E4130) Alloy Steel

About 4130 (E4130) Alloy Steel

Aircraft quality 4130 alloy steel is a medium carbon, low alloy steel containing 0.15/0.25% molybdenum and 0.80/1.10% chromium as strengthening agents. This type of steel is also commonly referred to as a chromoly steel, or chrome moly steel. Due to its relatively low carbon content of 0.28/0.33%. These 4130 steel properties offer exceptional weldability. With the proper heat treatment it is also readily machined. Annealing 4130 (E4130) alloy steel offers excellent ductility. 4130 steel can also be normalized or otherwise heat treated. Steel 4130 (E4130) has an excellent strength to weight ratio and is considerably stronger and harder than other standard grades of steel. Chromoly steels are especially useful in their ability to retain their bulk properties while allowing for significant hardness to be attained.

4130 (E4130) steel alloy is used primarily in the construction of commercial and military aircraft and ground support systems as well as automotive, race cars, off road, hydraulic tools, and machine tool applications. It is an intermediate strength material. Lighter gauges offer lighter weight but still maintain great strength, making it excellent for auto racing and aerospace. Engineers also use 4130 plate and bar steel for parts such as pins used to secure a critical assembly. These pins are designed to fail at a specific yield in order to avoid a catastrophic failure, and 4130 (E4130) alloy steel stands up to this test.

As one of the most focused suppliers of 4130 steel in the U.S., Benedict-Miller maintains one of the largest stocked inventories of aircraft quality (AQ) steel.

SAE 4130 Steel Chemical Composition: Typical Chemical Properties (%)

Carbon 0.28/0.33 Sulfur 0.025 max. Molybdenum 0.15/0.25
Manganese 0.40/0.60 Silicon 0.15/0.35 Nickel 0.25 max.
Phosphorus 0.025 max. Chromium 0.80/1.10 Copper 0.35 max.

Above chemistry applies to all of our AMS 6350, AMS, 6351 Specifications - Annealed,  AMS 6348, MIL S6758 Round Bar - Normalized, AMS 6345 Specifications - Normalized or otherwise Heat Treated.


AISI 4130 Aircraft Quality Steel Cut to Size and Delivered Quickly

With the largest stocked inventory of aircraft quality steel, Benedict-Miller delivers the best chromoly 4130 (E4130) alloy steel sheet, plate, or round bar cut and finished to your specifications when you need it. Call 1-908-497-1477 to speak with a knowledgeable, friendly AQ steel specialist who will provide you with a quick quote and immediate answers to your questions.

Representing only prime stock from world class mills, all our 4130 Alloy AQ steel is certified to Aerospace Material Specifications (mill certification available upon request). See more details about our 4130 chromoly steel stock including 4130 plate, 4130 sheet, 4130 round bar and 4130 flat bar (cut from plate) steel pages.


  • Largest stocked inventory for fast delivery
  • Prime stock only, highest quality for reliability, durability
  • Sheet, Plate, or Round Bar
  • AMS certified
  • DFARS compliance
  • Domestic material
  • Your Single Source Solution
  • Precision parts cut to your specifications using DXF files
  • ISO Certified
  • No minimum quantities


Representing Only Prime Stock from World Class U.S. Mills


Supplying the world AISI 4130 (E4130) and 4340 (E4340) Aircraft Quality Steel.
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