ThePipingMart Blog Grades Incoloy Alloy 864 (UNS S35135) – Composition, Uses, and Properties

Incoloy Alloy 864 (UNS S35135) – Composition, Uses, and Properties

Incoloy 864

UNS S35135 is a nickel-iron-chromium alloy designed for superior corrosion resistance in various applications. It has excellent resistance to oxidation and carburization at temperatures up to 1600°F. This makes it an ideal choice for many industrial uses, especially those that require extreme temperatures or harsh environments. Incoloy Alloy 864 (UNS S35135) is worth considering if you need a high-performance alloy for your industry. This specialized material is a nickel-chromium-iron-molybdenum alloy, which packs a serious punch. Thanks to its superior corrosion resistance, high strength and heat resistance, UNS S35135 is often used in demanding applications like chemical processing equipment, gas turbines, and industrial furnaces. And despite its incredible capabilities, this alloy is still highly machinable, making it easy for a wide range of applications. So, if you’re looking for a reliable and durable alloy, you can go right with Incoloy Alloy 864. Let’s take a look at this alloy in detail.

What Forms of Incoloy 864 is Available at Piping Mart?

  • Incoloy 864 Nuts
  • Incoloy 864 Bar
  • Incoloy 864 Bolt
  • Incoloy 864 Pipe
  • Incoloy 864 Screw
  • Incoloy 864 Tubing
  • Incoloy 864 Valves
  • Incoloy 864 Washers
  • Incoloy 864 Flanges
  • Incoloy 864 Fasteners
  • Incoloy 864 Electrodes
  • Incoloy 864 Stud Bolts
  • Incoloy 864 Sheet Plates
  • Incoloy 864 Pipe Fittings
  • Incoloy 864 Forged Fitting
  • Incoloy 864 Instrumentation Fittings

Incoloy 864 Composition

UNS S35135 contains the following elements as its main components: Nickel (Ni): 30%, Chromium (Cr): 20%, Iron (Fe): 40%, and Molybdenum (Mo): 1%. In addition, it also contains small amounts of Manganese, Cobalt, Copper, Silicon, and Carbon. This combination of elements gives Incoloy 864 superior strength and excellent corrosion resistance.

Element Content (%)
Nickel, Ni 30 – 38
Iron, Fe 29.105 – 45
Chromium, Cr 20 – 25
Molybdenum, Mo 4 – 4.8
Silicon, Si 0.60 – 1
Titanium, Ti 0.40 – 1
Carbon, C ≤ 0.080
Sulfur, S ≤ 0.015

Incoloy 864 Mechanical Properties

Regarding mechanical properties, Incoloy 864 has an ultimate tensile strength of 95 ksi and yield strength of 50 ksi. It also has good impact toughness at -320°F and excellent fatigue resistance at elevated temperatures. The alloy is also non-magnetic and highly resistant to scaling at high temperatures, making it suitable for vacuum furnaces.

Properties Metric Imperial
Tensile strength 648 MPa 94000 psi
Yield strength 109.6 MPa 15900 psi
Elongation at break 16.60% 16.60%

Incoloy 864 Chemical Properties

UNS S35135 is an iron-nickel-chromium alloy characterized by its exceptional oxidation and advertising resistance. This alloy maintains its strength and durability under extreme temperatures, making it a versatile material. The addition of titanium carbonitride strengthens the fundamental matrix while providing excellent wear and galling resistance. Its relatively low coefficient of thermal expansion makes Incoloy 864 ideal for applications that require precise shape and size maintenance over wide temperature ranges. Its high weldability, deep-drawing circumstances, formability, and machinability make this alloy a desirable option in industrial production processes.

Incoloy 864 Thermal Properties

Properties Metric Imperial
Thermal expansion co-efficient (@100°C/212°F) 14.7 µm/m°C 8.17 µin/in°F
Thermal conductivity (@23°C/73.4°F) 11 W/mK 76.3².°F

Incoloy 864 Physical Properties

UNS S35135 is an alloy made from a combination of nickel, iron and chromium that offers excellent resistance to oxidation and a wide range of corrosive elements. It also has excellent mechanical properties such as retention of strength again high temperatures, high tensile strength and good fatigue characteristics, making it ideal for applications subject to thermal cycling. The alloy can also be welded easily, withstanding the heat treatment required and avoiding significant hardening or distortion. Its elevated temperature capabilities make Incoloy 864 applicable in environments ranging from gas turbine components to nuclear power-island equipment, ensuring long-term reliability despite the challenging conditions it may face.

Properties Metric Imperial
Density 8.02 g/cm3 0.290 lb/in3
Melting point 1353-1393°C 2467-2539°F

Incoloy 864 Uses

UNS S35135 is widely used in chemical processing, oil refining, petrochemical processing, power generation, aerospace engineering and marine engineering. It is also used in high-temperature applications such as heat exchangers, boilers, gas turbines and nuclear reactors. Additionally, this alloy is often used as an alternative to other alloys, such as Monel K500 or Hastelloy C276 which are more expensive but offer similar performance characteristics.

Incoloy 864 Uses in Industries

Oil and Gas Industry

The oil and gas industry also utilizes Incoloy 864 for its superior corrosion resistance properties. The alloy is often used in offshore drilling platforms, where it can withstand exposure to saltwater and other corrosive elements. It is also commonly used in oil refineries and petrochemical plants for equipment such as heat exchangers, valves, and pumps.

Power Generation Industry

Incoloy 864 is a popular choice for power generation due to its ability to withstand high temperatures and corrosive environments. It is commonly used in gas turbines, steam turbines, boilers, and other power plant components exposed to extreme conditions. The alloy’s strength and resistance to oxidation make it a reliable material for these critical applications.

Aerospace Industry

The aerospace industry relies on Incoloy 864 for its exceptional strength-to-weight ratio and resistance to extreme temperatures. The alloy is often used in aircraft engines, which can withstand the intense heat generated during flight. It is also utilized in other aerospace components such as exhaust systems, landing gear, and structural parts.

Marine Industry

Incoloy 864’s corrosion-resistant properties also make it a valuable material for marine applications. It is commonly used in seawater desalination plants, offshore structures, shipbuilding, and underwater equipment because it can withstand the harsh marine environment without corroding or degrading over time.

Incoloy 864 Equivalents

  • ASTM A 240
  • ASTM A 480

Incoloy 864 Corrosion Resistance

Incoloy 864 is an alloy that offers superior corrosion resistance in various environments. In addition to its robust resistance to chemical attack and extreme heat, this alloy is highly resistant to stress-corrosion cracking, making it ideal for use in high-pressure and high-temperature applications where corrosive chemicals are present. Furthermore, Incoloy 864 has excellent formability properties, which make it easy to work with during manufacturing and installation. Incoloy 864 is the perfect choice for superior performance in resisting corrosion.

Incoloy 864 Heat Resistance

Incoloy 864 is a heat-resistant metal alloy designed to handle extreme temperatures. This makes it a vital component in manufacturing industrial components, such as furnaces, chemical reactors and reheater elements. With its great high-temperature strength, resistance to oxidation and excellent mechanical properties even in hostile conditions, UNS S35135 is the perfect metal alloy for applications with high temperatures. From its ability to control temperature decay over long periods and its hot yield strength, this alloy can maintain its properties despite continuous long exposure to elevated temperatures – something invaluable in industries relying on factors such as safety or efficiency.

Incoloy 864 Heat Treatment

Incoloy 864 is an alloy with a rare combination of properties, making it ideal for incredibly high-temperature applications. However, heat treatment is necessary to make the most of this alloy’s properties and bring out its strength. Effective Incoloy 864 heat treatment parameters are pretty exacting, requiring precise amounts of temperature and duration at specific points. By following the steps needed during heat treatment, the alloy can hit its ultimate maximum tensile strength at temperatures as high as 1300°C without any loss of flexural or impact fatigue strength. Heat treatment ensures that Incoloy 864 can perform in the toughest settings and deliver lasting results with superior ductility, creep resistance and stress rupture strength even at extreme temperatures.

Incoloy 864 Machining

Regarding machining Incoloy 864, special considerations must be taken due to its unique properties. This metal forgings alloy is highly resistant to oxidation and carburization at high temperatures, making it an ideal material for parts working in extreme environments. Choosing the correct cutting tools is paramount when machining components from Incoloy 864, as it is more challenging to machine than many other materials. Significant investment in tooling and properly trained personnel are required for the successful machining of this tough alloy. For these reasons, only experienced machinists should attempt to process components from Incoloy 864 for optimum efficiency and accuracy.

Incoloy 864 Welding

Incoloy 864 welding is an advantageous process that can join multiple metal alloys. With a melting point between 2136-2156℉, it can connect stainless steel, nickel alloys, and iron-based superalloys without generating harmful levels of fumes or gasses. Incoloy 864 welding tends to be a preferred choice of welders due to its convenience and added safety measures. In addition, it is alloy resistant, which means it will not corrode after completing the weld. Incoloy 864 welding is revered for its numerous benefits that aid in providing a secure bond.


Incoloy 864 is a versatile nickel-iron-chromium alloy that offers superior corrosion resistance in various applications. Its mechanical properties make it well suited for extreme temperatures or harsh environments, while its composition gives it excellent oxidation resistance even at high temperatures. Using this instead of other more expensive alloys can save money while still getting the performance you need from your components or equipment. If you are looking for an economical solution for your next project, consider Incoloy 864!

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