ThePipingMart Blog Grades AMS 6427 Alloy Steel – Composition, Properties and Uses

AMS 6427 Alloy Steel – Composition, Properties and Uses

AMS 6427

AMS 6427 is a common term among engineers and metallurgists. But it may sound like gibberish to those not in these professions. AMS 6427 is an alloy steel commonly used in the aerospace industry. In this blog, we will discuss the composition, physical properties, and mechanical properties of AMS 6427 and its uses, hardness, and recommended heat treatment.

What is AMS 6427

AMS 6427 (also known as Alloy Steel 4330) is a specification for a high-strength steel alloy that is often used in critical aerospace applications. This particular grade of steel is known for its exceptional toughness and ability to withstand high levels of stress and deformation without losing its structural integrity. As an expert in the field, I can confidently say that AMS6427 is among the most reliable and durable materials available for use in harsh environments, such as those encountered in the aerospace industry. If you are looking for high-performance steel that can meet the most demanding requirements, then AMS6427 is a perfect choice.

AMS 6427 Composition

AMS 6427 has a chemical composition of 0.15% Carbon, 0.30-0.60% Manganese, 0.040% Phosphorus max, 0.025% Sulfur max, 0.55-0.75% Nickel, 0.70-0.90% Chromium, 0.20-0.30% Molybdenum, and 0.15-0.25% Vanadium. It has a nominal density of 7.85 g/cm³ and a melting range of 1460-1525°C. AMS 6427 also has good corrosion resistance and excellent weldability.

Element Content (%)
Iron, Fe 95.3-98.1
Nickel, Ni 1.0-1.50
Manganese, Mn ≤ 1.0
Silicon, Si ≤ 0.80
Chromium, Cr 0.40-0.60
Molybdenum, Mo 0.30-0.50
Carbon, C 0.20-0.30

AMS 6427 Physical Properties

The physical properties of AMS 6427 include a tensile strength of 180 ksi, yield strength of 150 ksi, and an elongation at fracture of 12%. Its minimum hardness is 43 HRC, with a density of 7.85 g/cm³. The high tensile strength of AMS 6427 makes it ideal for aerospace applications, where materials must withstand extreme conditions.

Properties Metric Imperial
Melting point 1427°C 2600°F

AMS 6427 Mechanical properties

Mechanical properties of AMS 6427 include the ability to maintain its strength at high temperatures. It has excellent ductility, toughness, and fatigue strength. AMS 6427 has a Charpy impact value of 30 ft-lb at -65°F and is often used in critical structural applications requiring high strength and toughness.

Properties Metric Imperial
Tensile strength ≥ 860 MPa ≥ 125000 psi
Yield strength ≥ 690 MPa ≥ 100000 psi
Elongation at break (In 50 mm) ≥ 15.0 % ≥ 15.0 %
Hardness, Brinell 285 285

AMS 6427 Uses

AMS 6427 is commonly used in the aerospace and defence industries. It is often found in applications such as gears, fasteners, bearings, and high-strength structural components. Its strength and durability make it ideal for aircraft engines, landing gears, and control systems.

AMS 6427 Hardness

The hardness of AMS 6427 varies depending on the heat treatment it undergoes. In the annealed condition, it has a hardness of 207 HB, which increases to 248 HB in the normalized and tempered condition. If heat-treated to the precipitation-hardening condition, the hardness can reach up to 345 HB.

AMS 6427 Heat treatment

A recommended heat treatment for AMS 6427 is normalising it by heating it to 1650°F and soaking it for one hour per inch of thickness. After cooling in air, the material should be tempered by heating to 1300°F and soaking for one hour per inch of thickness before cooling in still air.


AMS 6427 material is a high-strength alloy steel with excellent mechanical properties commonly used in the aerospace and defence industries. Its composition, physical and mechanical properties, uses, hardness and heat treatment make it ideal for critical structural applications where strength, durability, and resistance to extreme conditions are necessary. Understanding the properties of AMS 6427 is crucial in choosing the right material for a particular application.

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