Nickel-based super alloy: Incoloy 800H (UNS N08810/W.Nr. 1.4958)

What is Incoloy 800H?

Incoloy 800H, also known as “Alloy 800H”, is designated as UNS N08810 or DIN W.Nr. 1.4958. It has almost the same chemical composition as Alloy 800 except that it requires a higher carbon addition resulting in improved high-temperature properties. Compared to Incoloy 800, it has better creep and stress-rupture characteristics in the 1100°F [592°C] to 1800°F [980°C] temperature range. While Incoloy 800 is usually annealed at at approximately 1800°F [980°C], Incoloy 800H should be annealed at approximately 2100°F [1150°C]. Besides, Alloy 800H has a coarser average grain size in accordance with ASTM 5.

Incoloy 800H (NO8810) nickel-based alloy alloys usually contain 15-25% Cr. The nickel content is 30-45%, and contains a small amount of aluminum and titanium. Compared with Incoloy 800 alloy, the carbon content is controlled from less than or equal to 0.1% to 0.05-0.1%, which better improves the strength of steel. The alloy has high chromium content and sufficient nickel content, so it has high high temperature corrosion resistance, 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 800h seamless pipe - Nickel-based super alloy: Incoloy 800H (UNS N08810/W.Nr. 1.4958)

Incoloy 800H seamless pipes cut into pieces. O.D=180mm, THK=18mm.

Chemical Composition Requirements of Incoloy 800H

The Chemical Composition of Incoloy 800, %
Nickel 30.0-35.0
Cromium 19.0-23.0
Iron ≥39.5
Carbon 0.05-0.10
Aluminum 0.15-0.60
Titanium 0.15-0.60
Manganese ≤1.50
Sulfur ≤0.015
Silicon ≤1.00
Copper ≤0.75
Al+Ti 0.30-1.20

Physical Properties of Incoloy 800H

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

Mechanical Properties of Incoloy 800H

astm b163 incoloy 800h seamless pipes - Nickel-based super alloy: Incoloy 800H (UNS N08810/W.Nr. 1.4958)

ASTM B163 Incoloy 800H, UNS N08810 seamless pipes, 1-1/4″ x 0.083″(W.T) x 16.6′(L).

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

Temperature ℃ σЬ/ MPa σ0.2 / MPa δ5 /%
100 425 140 160
300 390 95 115
500 360 80 100
600 300 75 95
  • The melting temperature range of Incoloy 800H (NO8810) nickel-based alloy: 1350~1400℃. 
  • Incoloy 800H (NO8810) nickel-based alloy specific heat capacity: 455J/(kg·℃). 
  • Density of Incoloy 800H (NO8810) nickel-based alloy: 8.0 g/cm3. 
  • Incoloy 800H (NO8810) nickel-based alloy magnetism: none.

Processing performance of nickel-based alloy incoloy 800h (UNS N08810): 

Thermal processing of nickel-based alloy incoloy 800h (UNS N08810):

  • (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 800H (NO8810) 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. 

Welding process of nickel-based alloy incoloy 800h (UNS N08810):

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 800H

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 800h (N08810):

Incoloy 800H Seamless Tubes Used for Synthetic Ammonia Facility

a newly constructed synthetic ammonia project in mexico - Nickel-based super alloy: Incoloy 800H (UNS N08810/W.Nr. 1.4958)

A newly constructed synthetic ammonia project in Mexico

Yaang has supplied Incoloy 800H seamless tubes for a synthetic ammonia project in Mexico constructed by a Chinese contractor.

  • Specification of the tubes: O.D= 141.3 mm (±1.2 mm), wall thickness= 18.5 mm (±4.6 mm), length= 4.3 m (±5.0 mm); the tube shall be furnished in annealed condition with grain size 5.
  • Working conditions: working temperature – 871°C; corrosive media: CO+H2+CO2+Steam; working pressure: 2.94 MPa.
  • Manufacture process: ASTM B404 UNS N08810 seamless tubes shall be fabricated by the following processes: electric arc furnace(EAF) + electro-slag remelting(ESR), hot & cold rolling and solution treatment.

Incoloy 800H Burner for A Methanol Plant’s Reformer

Yaang has supplied a reformer burner for an methanol plant in Egypt. The burner is made of high-temperature nickel alloy Incoloy 800H (UNS N08810).

reformer burner made of incoloy 800h for a methanol plant - Nickel-based super alloy: Incoloy 800H (UNS N08810/W.Nr. 1.4958)

The reformer burner made of Incoloy 800H for a methanol plant.

a methanol plant in egypt - Nickel-based super alloy: Incoloy 800H (UNS N08810/W.Nr. 1.4958)

The methanol plant in Egypt owned by Methanex Corp. Texaco coal gasification process is applied.

Incoloy 800H Used for Ethylbenzene Dehydrogenation in Styrene Project

The ethylbenzene dehydrogenation system is the core facility in production of styrene. Yaang has supplied large diameter bellows expansion joints and welded pipes made of Inoloy 800H (UNS N08810) to one of SINOPEC’s styrene project.

ethylbenzene dehydrogenation system in a sinopec styrene project - Nickel-based super alloy: Incoloy 800H (UNS N08810/W.Nr. 1.4958)

The ethylbenzene dehydrogenation system in a styrene project, 100000 mt/y, SINOPEC, Daqing.

Specification of the piping system:

  • design temperature & design pressure: 649°C & 170 kPa.
  • flow media: steam, ethylbenzene, styrene, CO2, CH4, H2, methylbenzene, catalysts, etc.
incoloy 800h bellows epansion joint for styrene project - Nickel-based super alloy: Incoloy 800H (UNS N08810/W.Nr. 1.4958)

Incoloy 800H bellows expansion joint, DN 1200.

welded pipe 24in std astm b514 n08810 - Nickel-based super alloy: Incoloy 800H (UNS N08810/W.Nr. 1.4958)

The Incoloy 800H welded pipe 24″ STD, made to ASTM B514 UNS N08810.

Incoloy 800H 90° Elbow 8″ L/R SCH40S (UNS N08810)

incoloy 800h uns 08810 90d elbow 8in sch40s - Nickel-based super alloy: Incoloy 800H (UNS N08810/W.Nr. 1.4958)

Incoloy 800H elbows L/R 90° SCH 40S, manufactured to ASTM B366 UNS N08810 & ASME B16.9

The UNS N08810 elbows are supplied to an UK client.

Varieties, specifications and supply status of Incoloy800h (N08810) nickel-based alloys:

Variety classification:

Yaang Pipe Industry can produce Incoloy 800h seamless pipes, Incoloy 800h pipe fitting, Incoloy 800h round bar, Incoloy 800h forgings, Incoloy 800h flanges of various specifications , Incoloy 800h ring, Incoloy 800h welded pipe, Incoloy 800h steel strip, Incoloy 800h 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 800H 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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