ThePipingMart Blog Grades AMS 5656 Stainless Steel – Composition, Properties, and Uses

AMS 5656 Stainless Steel – Composition, Properties, and Uses

AMS 5656

AMS 5656 is an air-melted speciality steel made from cobalt, chromium, molybdenum, and tungsten. This specialized alloy was designed to have superior properties for severe operating conditions. Unlike the common steels found in hardware stores or auto parts shops, AMS 5656 offers a variety of benefits that make it ideal for applications like aerospace components and medical equipment. In this blog post, we’ll discuss the composition of AMS 5656 and its unique physical and mechanical properties that allow it to outperform traditional materials. Plus, we will cover some common uses where you might find this type of alloy steel employed so you can get a better idea of its capabilities!

What is AMS 5656?

AMS 5656 (also known as Stainless Steel – Grade 21-6-9) is a highly sought-after material for corrosion and heat resistance. This steel alloy is designed for high-temperature applications and is often used in the aerospace and defence industries. Its exceptional strength and durability set AMS5656 apart from other materials, making it a reliable choice for demanding environments. Whether you require a tough material for jet engine parts or are in the market for a superior metal option for high-performance bearings, AMS5656 is a top pick for those who demand the best.

AMS 5656 Composition

AMS 5656 sheet is a nickel-based superalloy containing many elements, including iron, cobalt, chromium, molybdenum, tungsten, titanium, and aluminium. These elements work together to give the alloy its unique properties. The specific composition of AMS 5656 is 15% to 20% cobalt, 20% to 25% chromium, 10% to 15% molybdenum, and 2% to 3% titanium.

Element Content (%)
Iron, Fe 64
Chromium, Cr 20
Manganese, Mn 9
Nickel, Ni 6
Silicon, Si 1
Nitrogen, N 0.23
Carbon, C 0.080
Phosphorous, P 0.060
Sulfur, S 0.030

AMS 5656 Physical Properties

AMS 5656 has excellent physical properties, making it a standout alloy. It has a 0.287 pounds per cubic inch density and a melting point of 2620°F. The alloy has good resistance to oxidation, crevice corrosion, and pitting corrosion. Its thermal conductivity is high at 82 BTU-in/hr-ft²-°F. The alloy also has excellent electrical conductivity.

Properties Metric Imperial
Density 7.83 g/cm3 0.283 lb/in³

AMS 5656 Mechanical Properties

AMS 5656 tubing has superior mechanical properties that make it desirable in various industries. It has a high yield strength of 115 ksi and a tensile strength of 145 ksi. The alloy also has good thermal stability and can maintain strength and hardness at elevated temperatures. AMS 5656 also has high fatigue strength and is resistant to cracking and corrosion.

Properties Metric Imperial
Tensile strength, ultimate 883 MPa 128000 psi
Tensile strength, yield (@0.2%) 745 MPa 108000 psi
Elongation at break (in 50 mm) 56% 56%
Modulus of elasticity (typical for stainless steel) 200 GPa 29000 ksi
Machinability (based on 100 machinability for AISI 1212 steel) 30 30

Thermal Properties

Properties Metric Imperial
Thermal expansion co-efficient (@ 25-95°C/77-203°F) 16.7 µm/m°C 9.28 µin/in°F
Thermal conductivity (@-180°C/-292°C) 7.80 W/mK 54.1 BTU in/hr.ft².°F

AMS 5656 Equivalent

  • AMS 5561
  • AMS 5562
  • Stainless Steel Grade 21-6-9
  • UNS S21900
  • ASTM A269 (XM-10)
  • ASTM A276 (XM-10)
  • ASTM A312 (XM-10)
  • ASTM A314 (XM-10)
  • ASTM A412 (XM-10)
  • ASTM A479 (XM-10)
  • ASTM A580 (XM-10)
  • ASTM A813 (XM-10)
  • ASTM A814 (XM-10)

AMS 5656 Uses

AMS 5656 bars has numerous applications across various industries, including aerospace, defence, and oil and gas. The alloy is commonly used in turbine engine components, such as compressor blades, discs, and nozzles. It is also used in chemical processing, marine, and cryogenic applications. The alloy is preferred in these industries due to its excellent corrosion resistance, mechanical strength, and thermal stability.

AMS 5656 Hardness

AMS 5656 is a hard alloy with a Rockwell hardness of 38 HRC. This hardness level is optimal for applications that require wear and tear resistance, such as turbine blades and discs. The hardness level also enables the alloy to maintain its structural integrity, even at high temperatures.

AMS 5656 Heat Treatment

AMS 5656 material can be heat treated to improve its mechanical properties. Heat treatment includes solution treatment, which involves heating the alloy to a specific temperature and cooling it quickly. This process helps to refine the grain structure and improve the alloy’s mechanical properties.


AMS 5656 material is an alloy widely used in various industries due to its excellent physical and mechanical properties, resistance to corrosion, and thermal stability. The composition, physical and mechanical properties, uses, hardness, and heat treatment of AMS 5656 make it an ideal material for challenging applications in extreme environments. Industries that require high-strength, corrosion-resistant, and durable materials will find AMS 5656 valuable.

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