ThePipingMart Blog Grades Incoloy Alloy 27-7MO (UNS S31277) – Composition, Properties, and Uses

Incoloy Alloy 27-7MO (UNS S31277) – Composition, Properties, and Uses

Incoloy 27-7mo

Have you heard of Incoloy 27-7mo? If you haven’t, it’s time to explore this nickel-based alloy with superior resistance to extreme temperatures and corrosion. Incoloy 27-7mo is increasingly becoming popular in various industries, particularly in the oil and gas, nuclear, chemical, and aerospace fields. This blog post aims to provide valuable insights into what makes Incoloy 27-7mo special and its benefits in various applications.

Incoloy 27-7MO Composition

Incoloy 27-7mo boasts a unique chemical composition, with high nickel, molybdenum, and chromium levels and a low carbon, silicon, and iron percentage. This composition gives it excellent resistance to severe environments and makes it suitable for continuous use at high temperatures of up to 1000°C (1832°F).

Element Content (%)
Iron, Fe 35.54-46.2
Nickel, Ni 26-28
Chromium, Cr 20.5-23
Molybdenum, Mo 6.5-8
Manganese, Mn ≤3
Others Remainder

Incoloy 27-7MO Physical Properties

Incoloy 27-7mo has unique physical properties, including low thermal expansion, high thermal conductivity, and high electrical conductivity. It also maintains its mechanical strength even at high temperatures, making it ideal for heat exchangers, furnace components, and pressure vessels requiring high thermal resistance.

Properties Metric Imperial
Density 8.02 gm/cm3 0.290 lb/in3

Incoloy 27-7MO Mechanical Properties

The mechanical properties of Incoloy 27-7mo enable it to withstand high-stress environments, including those requiring high-temperature tensile, yield, and elongation strengths. It has excellent flexibility and can be cold-worked or hot-formed to suit various applications.

Properties Metric Imperial
Tensile strength(annealed) 827 MPa 120 ksi
Yield strength(annealed) 414 MPa 60 ksi
Elongation at Break( in 2 in 50 mm) 50% 50%
Poissons Ratio 0.29 0.29
Modulus of Elasticity 138 GPa 20000 ksi
Hardness, Rockwell B 95 95
Hardness, Vickers (0% cold work) 225 225

Incoloy 27-7MO Uses

Incoloy 27-7mo applies in various sectors, from the aerospace and nuclear industries to petrochemical and chemical processing. Its excellent resistance to corrosion makes it an excellent material for valves, pumps, and other components used to transfer or contain acidic and alkaline substances. Also, it is used to produce gas turbines and heat exchangers, where high temperatures and harsh conditions are common.

Incoloy 27-7MO Hardness

The hardness of Incoloy 27-7mo plays a significant role in its appropriate use in different applications. It has a Rockwell hardness of B93, comparable to many stainless steel alloys. However, with increased work hardening, its hardness can rise to B60.

Incoloy 27-7MO Heat Treatment

The heat treatment of Incoloy 27-7mo is crucial in enhancing its strength and durability. Depending on the desired physical and mechanical properties, the alloy can undergo annealing, quenching, or precipitation hardening. Precipitation hardening treatments have been used extensively to improve the alloy’s properties, enhancing its strength and durability.


Incoloy 27-7mo is a unique nickel-based alloy with excellent physical, mechanical, and chemical properties, making it ideal for high-stress and extreme-temperature applications. Its excellent resistance to both corrosion and heat, combined with its mechanical robustness, means that it can be used in multiple corrosion-critical components in harsh environments. Incoloy 27-7mo is rapidly becoming popular in various industries, making it a material to watch in the coming years.

Related Post