4130 (E4130) Alloy Steel

AISI 4130 (E4130) Aircraft Quality Steel Delivered When You Need It!

About 4130 (E4130) Alloy Steel

Aircraft quality 4130 (E4130) 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%, it offers exceptional weldability. With the proper heat treatment it is also readily machined. Annealing 4130 (E4130) alloy steel offers excellent ductility. It can also be normalized or otherwise heat treated. 4130 (E4130) alloy steel 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 (E4130) alloy 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.

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.

AMS 6350/51 Specifications - Annealed   AMS 6348/AMS S6758 Round Bar - Normalized

AMS 6345 Specifications - Normalized or otherwise Heat Treated


Quality Raw Materials from Prime Stock

With the largest stocked inventory of aircraft quality steel, Benedict-Miller delivers the best 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.

Our long-standing relationship with vendors ensures you the highest quality raw materials. Representing only prime stock from world class mills, all our AQ steel is certified to Aerospace Material Specifications (mill certification available upon request). Our diverse supply chain ensures you get the right material for your projects.


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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. Or place a request for quote online now using our convenient form.

  • 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
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  • Precision parts cut to your specifications using DXF files
  • ISO Certified
  • No minimum quantities

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