ThePipingMart Blog Grades AMS 5668 Inconel Alloy – Composition, Properties, and Uses

AMS 5668 Inconel Alloy – Composition, Properties, and Uses

AMS 5668

AMS5668, also known as Inconel 718, is a nickel-based superalloy with high strength and excellent performance in various applications. It can withstand temperatures of up to 1300°F and is resistant to oxidation, corrosion, and erosion. AMS5668 is widely used in aerospace, gas turbine, and chemical processing industries. In this blog post, we will delve into the various aspects of AMS 5668, including its composition, properties, uses, hardness, and heat treatment.

What is AMS 5668?

AMS 5668 ( also known as Inconel X-750) is a high-performance metal alloy that has garnered attention for its impressive mechanical properties. This alloy is composed primarily of nickel and smaller amounts of titanium and aluminium, making it an ideal material for demanding applications. AMS5668 metal has excellent corrosion resistance, high strength at elevated temperatures, and exceptional durability. It is commonly used in aerospace, automotive, and medical industries, where reliability and performance are paramount. Its widespread use in critical components underscores its reliability and importance in ensuring safety and reliability in technological advancements.

What Form Is AMS 5668 Available at Piping Mart?

  • Inconel X750 Bars
  • Inconel X750 Nuts
  • Inconel X750 Bolts
  • Inconel X750 Screw
  • Inconel X750 Washer
  • Inconel X750 Fasteners
  • Inconel X750 Stud Bolts
  • Inconel X750 Sheet Plates

AMS 5668 Composition

AMS 5668 consists of nickel, chromium, and iron as its primary components, followed by smaller amounts of molybdenum, niobium, titanium, cobalt, aluminium, and manganese. These elements combine to create a high-strength, corrosion-resistant alloy that can withstand extreme conditions. Its chemical composition is typically 50-55% nickel, 17-21% chromium, 4.75-5.5% niobium, and 2.8-3.3 % molybdenum.

Element Content (%)
Chromium, Cr 14-17
Iron, Fe 5-9
Titanium, Ti 2.25-2.75
Manganese, Mn 1 max
Niobium, Nb 0.7-1.2
Copper, Cu 0.5 max
Silicon, Si 0.5 max
Aluminum, Al 0.4-1
Carbon, C 0.08 max
Sulfur, S 0.01 min
Nickel, Ni Remainder

AMS 5668 Physical Properties

AMS 5668 has excellent physical properties, making it ideal for high-temperature environments. It has a density of 8.19 g/cm³, a melting point of 2300°F, and a boiling point of 5019°F. Its thermal conductivity is 6.4 BTU/ft²/h/°F, and its electrical conductivity is 1.14%IACS. Additionally, it has a coefficient of thermal expansion of 7.7 x 10^-6 /°F.

Properties Metric Imperial
Density 8.26 g/cm³ 0.298 lb/in³
Melting point 1413°C 2575°F

AMS 5668 Mechanical Properties

AMS 5668 exhibits high strength, fatigue resistance, and toughness, making it a popular choice in critical applications. Its ultimate tensile strength (UTS) is 135 ksi, and its yield strength is 70 ksi. Its elongation at break is 20%, and its hardness is typically 40 HRC. Its fatigue strength is 110 ksi, making it an ideal material for applications subjected to cyclic loading.

Properties Metric Imperial
Tensile strength 1325 MPa 192.2 ksi
Elongation at break (in 51 mm) 23.60% 23.60%
Reduction of area 42% 42%

AMS 5668 Equivalent

AISI 688 AMS 5598 AMS 5670 AMS 5747 GE B50TF1232
AMS 5542 AMS 5667 AMS 5671 ASTM B637 GE B50YP44
AMS 5582 AMS 5668 AMS 5698 DIN 2.4669 MIL N-24114
AMS 5583 AMS 5669 AMS 5699 DIN 2.4699 MIL N-7786

AMS 5668 Uses

AMS 5668 is widely used in aerospace, gas turbine, and chemical processing industries due to its high strength, resistance to heat and corrosion, and excellent performance. It is used in engine components, exhaust systems, heat exchangers, and needle valves, among other applications. It is also used in cryogenic environments due to its low-temperature properties.

AMS 5668 Hardness

AMS 5668 has a typical hardness of 40 HRC. It can be further hardened through various heat treatment processes. For example, it can be solution annealed at 1950°F for 30 minutes, followed by air cooling or oil quenching. This process enhances its strength and ductility.

AMS 5668 Heat Treatment

AMS 5668 can be heat treated to improve its properties further. The solution annealing process mentioned above is typically followed by ageing at a lower temperature of 1325°F for up to 8 hours. This process enhances the material’s strength, stiffness, and fatigue life. Other heat treatment processes include precipitation hardening and double ageing.


AMS 5668 material is a nickel-based superalloy that offers high strength, excellent resistance to heat and corrosion, and superior performance in critical applications. Its composition, physical and mechanical properties, uses, hardness and heat treatment techniques make it an indispensable material in various industries that require high-performance materials. Understanding these aspects of AMS 5668 is essential for adequately selecting, designing with, and using it for optimal results.

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