INCOLOY alloy 800 (UNS N08800, W. Nr. 1.4876) is a widely used material for construction of equipment requiring corrosion resistance, heat resistance, strength, and stability for service up to 1500°F (816°C). Alloy 800 offers general corrosion resistance to many aqueous media and, by virtue of its content of nickel, resists stress corrosion cracking. At elevated temperatures it offers resistance to oxidation, carburization, and sulfidation along with rupture and creep strength. For applications requiring greater resistance to stress rupture and creep, especially at temperatures above 1500°F (816°C), INCOLOY alloys 800H and 800HT are used.
Incoloy Alloy 800
INCOLOY alloy 800 (UNS N08800, W. Nr. 1.4876) is a widely used material for construction of equipment requiring corrosion resistance, heat resistance, strength, and stability for service up to 1500°F (816°C). Alloy 800 offers general corrosion resistance to many aqueous media and, by virtue of its content of nickel, resists stress corrosion cracking. At elevated temperatures it offers resistance to oxidation, carburization, and sulfidation along with rupture and creep strength. For applications requiring greater resistance to stress rupture and creep, especially at temperatures above 1500°F (816°C), INCOLOY alloys 800H and 800HT are used.
INCOLOY alloy 800 is used in a variety of applications involving exposure to corrosive environments and high temperatures. It is used for heat-treating equipment such as baskets, trays, and fixtures. In chemical and petrochemical processing, the alloy is used for heat exchangers and other piping systems in nitric acid media especially where resistance to chloride stress-corrosion cracking is required. In nuclear power plants, it is used for steam-generator tubing. The alloy is often used in domestic appliances for sheathing of electric heating elements. In the production of paper pulp, digester-liquor heaters are often made of alloy 800. In petroleum processing, the alloy is used for heat exchangers that air cool the process stream.
Chemical Composition
Limiting Chemical Composition, % by Weight
Nickel……………………………………………………………………….30.0-35.0
Chromium………………………………………………………………….19.0-23.0
Iron……………………………………………………………………………39.5min.
Carbon……………………………………………………………………..0.10max.
Manganese……………………………………………………………….1.50max.
Sulfur……………………………………………………………………..0.015max.
Silicon………………………………………………………………………..1.0max.
Copper……………………………………………………………………..0.75max.
Aluminum………………………………………………………………….0.15-0.60
Titanium……………………………………………………………………0.15-0.60
Physical Properties
The following table discusses the physical properties of INCOLOY alloy 800.
| Properties | Metric | Imperial |
|---|---|---|
| Density | 7.94 gm/cm3 | 0.287 lb/in3 |
Mechanical Properties
The mechanical properties of INCOLOY alloy 800 are tabulated below.
| Properties | Metric | Imperial |
|---|---|---|
| Tensile strength(annealed) | 600 MPa | 87 ksi |
| Yield strength(annealed) | 275 MPa | 39.9 ksi |
| Elongation at Break | 45% | 45% |
Other Designations
Some of the designations used to denote INCOLOY alloy 800 are listed below:
| UNS N08800 | AMS 5766 | AMS 5871 | ASTM B163 | ASTM B366 |
| ASTM B407 | ASTM B408 | ASTM B409 | ASTM B514 | ASTM B515 |
| ASTM B564 | DIN 1.4876 |
Forming
This alloy exhibits good ductility and hence can be formed using conventional methods.
Hot working
INCOLOY alloy 800 can be hot worked at temperature ranges of 871-1232°C (1600-2250°F).
Cold Working
Cold working may be done on the alloy using standard tooling.
Annealing
INCOLOY alloy 800 may be annealed after cold working. Annealing should be done at 982°C (1800°F) for 15 min and then the alloy should be air cooled.
Applications
INCOLOY alloy 800 is used in the following applications:
- Heat exchangers
- Carburising equipment
- Heating elements
- Sheathing and nuclear steam generator tubing.