Summary:
A nickel-chromium alloy with good strength and excellent resistance to oxidation and carburization in high-temperature atmospheres. It also resists corrosion by many aqueous environments. The alloy maintains a stable, austenitic structure during prolonged exposure to high temperatures. Used for process piping, heat exchangers, carburizing equipment, heating element sheathing, and nuclear steam-generator tubing.
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Standard Product Forms:
Pipe, tube, sheet, strip, plate, round bar, flat bar, forging stock, hexagon and wire
Chemical Composition wt,%:
Physical Constants:
Density: 7.94g/cm3
Melting Range:1357-1385 ℃
Typical Mechanical Properties: (Annealed)
Rupture Strength(1000h):
1000°F/540°C 48Ksi, 360Mpa
1100°F/595°C 32Ksi, 160Mpa
1200°F/650°C 21Ksi, 50Mpa
1300°F/705°C 11Ksi, 18Mpa
Microstructure:
Incoloy 800 is an austenitic, solid-solution alloy and has a face-cetered-cubic structure. Titanium nitrides, titanium carbides, and chromium carbides normally appear in the alloy’s microstructure.
Characters:
Incoloy 800H is characterized by:
l Good creep-rupture properties at temperatures above 600 degree centigrade without loss of ductility during long-term use at temperatures below 700 degree centigrade, due to limilation of (Ti+Al) content to max.0.7%;
l Good resistance to reducing, oxidizing and nitriding atmospheres and to atmospheres which alternate between reducing and oxidizing conditions;
l Metallurgical stability in long-term application at high temperatures.
Incoloy 800HT is characterized by:
l Excellent creep strength at temperature above 700 degree centigrade. However, for applications where frequent excursions to temperatures lover than 700 degree centigrade during service cannot be excluded or parts of the material are permanently exposed to a temperature below 700 degree centigrade, the use of Incoloy 800H is recommended.
l Good resistance to reducing, oxidizing and nitriding atmospheres and to atmospheres which alternate between reducing and oxidizing conditions;
l Metallurgical stability in long-term application at high temperatures.
Corrosion Resistance:
Incoloy 800, like many austenitic stainless steels, can be sensitized, or made susceptible to intergranular attack in some aggressive media, by exposure to the temperature range of 1000 to 1400F.
Applications:
For services below 600 degree centigrade the use of soft annealed incoloy 800 is suggested. Incoloy 800 has applications in furnae components and equipment, petrochemical furnace cracker tubes, pigtails,headers and sheathing for electrical heating elements.
