ThePipingMart Blog Grades SAE AMS-S-6758 Steel – Composition, Properties, and Uses

SAE AMS-S-6758 Steel – Composition, Properties, and Uses


Knowing the standards used to produce the products we use daily is vital as a consumer. One such standard used in producing high-quality metals is the AMS-S-6758. This standard outlines aeronautical manufacturers’ requirements to create materials suitable for their products. This blog post will discuss everything you need to know about AMS-S-6758, from its composition, physical and mechanical properties, uses, hardness, and heat treatment.

What is AMS-S-6758?

This document specifies steel bars, forgings, and tubing used in aircraft engines and other high-performance applications. The AMS-S-6758 standard outlines these materials’ properties, quality, and testing requirements, ensuring that they meet the rigorous demands of the aerospace industry. It’s important to adhere to this specification to ensure the safety and reliability of aircraft engines, making AMS-S-6758 a vital component in the aviation field.

AMS-S-6758 Composition

AMS-S-6758 is a carbon steel alloy with a low carbon content, making it highly weldable. The alloy contains chromium, molybdenum, and vanadium, strengthening the steel’s corrosion resistance properties. Additionally, the alloy has a nickel content that improves its toughness.

AMS-S-6758 Physical Properties

AMS-S-6758 has excellent physical properties. It has a density of 0.284 lb/in³, a thermal conductivity of 24 Btu/(hr/ft²/°F), and a specific heat of 0.11 Btu/(lb/°F). The alloy’s melting point stands at approximately 2,800°F, and its coefficient of thermal expansion is 6.6×10^-6 in/(in·°F).

AMS-S-6758 Mechanical Properties

The mechanical properties of AMS-S-6758 include its ultimate tensile strength, yield strength, elongation, and reduction in area. The minimum ultimate tensile strength it displays is 240 ksi (kilopounds per square inch), while the minimum yield strength is 180 ksi. Additionally, it has an elongation of 10% and a minimum reduction floating area of 40%.

AMS-S-6758 Uses

AMS-S-6758 is a versatile alloy used in making various aeronautical components. It is commonly used to produce aircraft landing gear because of its exceptional corrosion resistance properties. Moreover, it is used to manufacture shafts, gears, and structures in aircraft engines due to its low carbon composition, which makes it highly compatible with welding applications.

AMS-S-6758 Hardness

AMS-S-6758 has a minimum hardness requirement of 248 HB (Brinell Hardness). This hardness requirement ensures that the alloy is not easily scratched or dented, making it suitable for high-stress applications.

AMS-S-6758 Heat Treatment

AMS-S-6758 is heat-treated to achieve the desired mechanical properties for different applications. The alloy requires normalizing or annealing before the hot working process involves rolling or forging. The subsequent heat treatment may include hardening and tempering.


It is crucial to understand the composition, mechanical and physical properties, uses, and heat treatment requirements of any alloy you intend to use, such as AMS-S-6758. This alloy’s exceptional properties, including its weldability, excellent corrosion resistance, and enhanced toughness, make it a popular choice in the aeronautical industry. It is perfect for producing high-stress components such as landing gear, shafts, and engine structures. Additionally, the heat treatment process determines the final properties of the alloy, making it suitable for different applications.

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