 |
INCOLOY 800 （UNS N08800) |
INCOLOY 800H&800HT (UNS N08810&N08811) |
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, heatingelement sheathing, and nuclear steam-generator tubing.
|
Nickel-iron-chromium alloys having the same basic composition as INCOLOY alloy 800 but with significantly higher creep-rupture strength. The higher strength results from close control of the carbon, aluminum, and titanium contents in conjunction with a high-temperature anneal. Used in chemical and petrochemical processing, in power plants for super-heater and reheater tubing, in industrial furnaces, and for heat-treating equipment. |
Standard
Product Forms
|
Pipe, tube, sheet, strip, plate, round bar, flat bar, forging stock, hexagon and wire.
|
Pipe, tube, sheet, strip, plate, round bar, flat bar, forging stock, hexagon and wire.
|
| Limiting Chemical Composition, % |
| |
Min. |
Max. |
|
Min. |
Max. |
|
Min. |
Max. |
| Ni |
30.0 |
35.0 |
Cu |
|
0.75 |
C |
|
0.1 |
| Cr |
19.0 |
23.0 |
Co |
|
|
Si |
|
1.0 |
| Fe |
39.5 |
|
Al |
0.15 |
0.6 |
P |
|
|
| Mo |
|
|
Ti |
0.15 |
0.6 |
S |
|
0.015 |
| Wo |
|
|
Mn |
|
1.5 |
N |
|
|
|
| |
Min. |
Max. |
|
Min. |
Max. |
|
Min. |
Max. |
| Ni |
30.0 |
35.0 |
Al800H |
0.15 |
0.6 |
Al+Ti (800HT) |
0.85 |
1.2 |
| Cr |
19.0 |
23.0 |
Al800HT |
0.15 |
0.6 |
| Fe |
39.5 |
|
Ti800H |
0.15 |
0.6 |
Si |
|
1 |
| C800H |
0.05 |
0.1 |
Ti800HT |
0.15 |
0.6 |
S |
|
0.015 |
| C800HT |
0.06 |
0.1 |
Mn |
|
1.5 |
Cu |
|
0.75 |
|
Physical
Constants
|
| Density,g/cm3 |
|
7.94 |
| Melting Range,℃ |
|
1357-1385 |
|
| Density,g/cm3 |
|
7.94 |
| Melting Range,℃ |
|
1357-1385 |
|
Typical
Mechanical
Properties
|
| (Annealed) |
|
|
|
|
|
|
| Rupture Strength(1000h) |
|
|
|
|
|
|
ksi |
Mpa |
| 1000°F/540°C |
|
|
|
|
|
|
48 |
360 |
| 1100°F/595°C |
|
|
|
|
|
|
32 |
160 |
| 1200°F/650°C |
|
|
|
|
|
|
21 |
50 |
| 1300°F/705°C |
|
|
|
|
|
|
11 |
18 |
| |
|
|
|
|
|
|
|
|
|
| (Annealed) |
|
|
|
|
|
|
| Rupture Strength(1000h) |
|
ksi |
Mpa |
| 1200°F/650°C |
|
|
|
|
24 |
165 |
| 1300°F/705°C |
|
|
|
|
15 |
105 |
| 1400°F/760°C |
|
|
|
|
10 |
70 |
| 1600°F/870°C |
|
|
|
|
4.7 |
32 |
| 1800°F/980°C |
|
|
|
|
2 |
14 |
|
 |
 |
| 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.
|
Incoloy 800H and 800HT ,as the same to the Incoloy 800,are also austenitic, solidsolution alloys. Titanium nitrides, titanium carbides, and chromium carbides normally appear in the alloys’
microstructure.
|
Characters
|
Incoloy 800H and 800HT are both austenitic high-strength solid-solution nickel-iron-chromium alloy with controlled levels of carbon, aluminium, titanium, silicon and manganese and controlled content of (Al + Ti). The analyses are similar to that of Incoloy 800,but a special solution anneal treatment (with grain sizes ≥ 90 μm/ASTM No. 4) gives significantly increased creep-rupture strength for Incoloy 800H above 600 ℃ and highest creep-rupture strength for Incoloy 800HT above 700 ℃ due to the precipitation of TiC.
|
Incoloy 800H is characterized by:
1. Good creep-rupture properties at temperatures above 600 °C (1110 °F) without loss of ductility during long-term
use at temperatures below 700 °C (1290 °F), due to limitation of (Ti + Al) content to max. 0.7 %;
2. Good resistance to reducing, oxidizing and nitriding atmospheres and to atmospheres which alternate between reducing and oxidizing conditions;
3. Metallurgical stability in long-term application at high temperatures. |
Incoloy 800HT is characterized by:
1. Excellent creep strength at temperature above 700℃ .However, for applications where frequent excursions to temperatures lower than 700℃ during service cannot be excluded or parts of the material are permanently exposed to a temperature below 700℃, the use of Incoloy 800H is recommended.
2. Good resistance to reducing, oxidizing and nitriding atmospheres and to atmospheres which alternate between reducing and oxidizing conditions;
3. 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 1400°F (540–760°C). |
| Alloys 800, 800H and 800HT have the same nickel, chromium, and iron contents and generally display similar corrosion resistance. The high nickel and chromium contents of Incoloy 800H, 800HT and 800 ensure excellent resistance to oxidation.Compared to Incoloy 800,the 800H and 800HT can be used at higher temperature and still have a good strenth,the alloys are also very resistant to carburization, nitridation and oxidizing sulphur-bearing atmospheres at high temperature.Resistance to hydrogen is excellent for Incoloy 800H and 800HT. |
|
| Applications |
| For services below 600℃ the use of soft annealed Incoloy 800 is suggested.Incoloy 800 has applications in furnace components and equipment, petrochemical furnace cracker tubes, pigtails and headers, and sheathing for electrical heating |
1. Steam/hydrocarbon reforming for components such as: transfer piping, catalyst tubes (in lowpressure processes) and quench-system piping；
2. Cracking tubes used in the production of acetic anhydride and ketene – high strength, resistance to carburization and to dry hydrogen chloride and chlorine；
3. Components, e.g. heat exchangers, piping systems etc., in coal conversion plants。 |
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