Nickel-based super alloy: Incoloy 800 (UNS N08800/W.Nr. 1.4876)

What is Incoloy 800?

Designated as UNS N08800 or DIN W.Nr. 1.4876, Incoloy 800 (also known as “Alloy 800”) is an iron-nickel-chromium alloy with good strength and excellent resistance to oxidation and carburization in high-temperature atmospheres. It also has excellent resistance to corrosion by many aqueous environments and resistance to chloride stress-corrosion cracking. Incoloy 800 alloy maintains a stable austenitic structure during prolonged exposure to high temperatures since it doesn’t form the embrittling sigma phase after long time exposure at 1200°F [649°C]. It’s mainly used for petrochemical process piping, heat exchangers, carburizing equipment, heating element sheathing, and nuclear steam generator tubing.

Incoloy 800 (UNS N08800) has a high chromium content and a sufficient nickel content, so it has a high resistance to high temperature corrosion, and it is widely used in industry. In chloride, low concentration NaOH aqueous solution and high temperature and high pressure water, it has excellent stress corrosion cracking resistance, so it is used to manufacture stress corrosion cracking resistance equipment. Corrosion resistance is better than general austenitic stainless steel, and better than Inconel 600 alloy; in the manufacture of corrosion-resistant stress cracking equipment, it is better than Inconel 600 and Monel 400 alloy.

incoloy 800 flange weld neck - Nickel-based super alloy: Incoloy 800 (UNS N08800/W.Nr. 1.4876)

ASTM B564 Incoloy 800 weld neck flange, 3″ SCH80 600#, ASME B16.5.

Chemical Composition Requirements of Incoloy 800

The Chemical Composition of Incoloy 800, %
Ni 30.0-35.0
Cr 19.0-23.0
Fe ≥39.5
Ti 0.15-0.60
Al 0.15-0.60
C ≤0.10
Mn ≤1.50
Si ≤1.00
S ≤0.015
Cu ≤0.75

Physical Properties of Incoloy 800

Density Melting Range Specific Heat Electrical Resistivity
g/cm3 °C °F J/kg. k Btu/lb.°F µΩ·m
7.94 1357-1385 2475-2525 460 0.110 989

Temperature ℃ σЬ/ MPa σ0.2 / MPa δ5 /%
100 425 140 160
300 390 95 115
500 360 80 100
600 300 75 95
  • Incoloy 800 (N08800) alloy melting temperature range: 1350~1400℃. 
  • Incoloy 800 (N08800) alloy specific heat capacity: 455J/(kg·℃). 
  • Incoloy 800 (N08800) alloy density: 8.0 g/cm3. 
  • Incoloy 800 (N08800) alloy magnetism: none. 

Mechanical Properties of Incoloy 800

Tensile Strength, min. Yield Strength, min. Elongation, min. Hardness, min.
Mpa ksi Mpa ksi % HB
600 87 295 43 44 138

Processing performance of nickel-based alloy incoloy 800 (N08800)

Incoloy 800 (N08800) alloy hot processing:

  • (1) The temperature range is 1200℃~950℃, and the cooling method is water quenching or rapid air cooling. 
  • (2) In order to obtain the best performance and creep resistance, solution treatment should be carried out after thermal processing.
  • (3) The material can be directly fed into the furnace that has been heated to 1200°C, and after holding for sufficient time, the material can be quickly discharged, and thermal processing can be carried out in the specified temperature range. When the material temperature drops below the thermal processing temperature, it needs to be reheated. 

Cold processing of Incoloy 800 (N08800) alloy:

  • (1) The work hardening rate is greater than that of austenitic stainless steel, so the processing equipment needs to be selected. The cold-worked material should be in a solution heat-treated state, and intermediate annealing should be carried out when the amount of cold work is large. 
  • (2) If the amount of cold working is greater than 10%, the workpiece needs to be treated with a second solution. 

Incoloy 800 (N08800) alloy welding process:

suitable for welding with the same material or other metals using any traditional welding process, such as tungsten electrode inert gas arc welding, plasma arc welding, manual sub-arc welding, metal inert gas arc welding, MIG welding, pulse arc welding is the first choice. If manual arc welding is used, it is recommended to use (Ar+He+H2+CO2) as the shielding gas. 

Product Forms and Standards of Incoloy 800

Product From Standard
Rod and Bar ASTM B408, EN 10095
Plate, Sheet & Strip ASTM A240, A480, ASTM B409, B906
Seamless Pipe & Tube ASTM B829, B407
Welded Pipe & Tube ASTM B514, B515, B751, B775
Welded fittings ASTM B366
Forging ASTM B564, DIN 17460

Application areas of nickel-based alloy incoloy 800 (N08800):

Varieties, specifications and supply status of Incoloy800 (N08800) nickel-based alloys:

Variety classification:

Yaang Pipe Industry can produce Incoloy800 seamless pipes, Incoloy800 pipe fitting, Incoloy800 round bar, Incoloy800 forgings, Incoloy800 flanges of various specifications , Incoloy800 ring, Incoloy800 welded pipe, Incoloy800 steel strip, Incoloy800 wire and supporting welding materials. 

Delivery status:

  • Seamless pipe: solid solution + acid white, length can be set; plate: solid solution, pickling, trimming;
  • Welded pipe: solid solution acid white + RT% flaw detection, forging: annealing + car polish; 
  • Bars are forged and rolled, surface polished or car polished; strips are delivered after cold rolling, solid solution soft state, and deoxidized; 
  • Wire rods are finely ground in solid solution pickled disk or straight strips, solid solution straight strips Delivery in light state.

Source: China Incoloy 800 Flanges Manufacturer – Yaang Pipe Industry (

(Yaang Pipe Industry is a leading manufacturer and supplier of nickel alloy and stainless steel products, including Super Duplex Stainless Steel Flanges, Stainless Steel Flanges, Stainless Steel Pipe Fittings, Stainless Steel Pipe. Yaang products are widely used in Shipbuilding, Nuclear power, Marine engineering, Petroleum, Chemical, Mining, Sewage treatment, Natural gas and Pressure vessels and other industries.)

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