Incoloy 800 1.4876 (Alloy 800, UNS NO8800) designed to resist Oxidation and Carburization. The general corrosion resistance is excellent.Incoloy alloy 800 is a widely used material of construction for equipment that must have high strength and resist oxidation, carburization, and other harmful effects of high temperature exposure. (For high temperature applications requiring optimum creep and rupture properties, Incoloy alloys 800H and 800HT are used).

The chromium in the alloy imparts resistance to oxidation and corrosion. The high percentage of nickel maintains an austenitic structure so that the alloy is ductile. the nickel content also contributes resistance to scaling, general corrosion, and stress-corrosion cracking. The iron content provides resistance to internal oxidation.

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 exchanger 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 liquid heaters are often made of alloy 800. In petroleum processing , the alloy is used for heat exchanger that air-cool the process stream.



A Ni-Cr-Fe alloy that resists high temperature oxidation. This alloy is a first choice for an upgrade from the 300 series stainless steel when improved performance or strength at temperature is required. For higher ASME Boiler and Pressure Code design values, consider Alloy 800HT.

Incoloy alloy 800 is particularly useful for high-temperature equipment in the petrochemical industry because the alloy doesn't form the embrittling sigma phase after long time exposure at 1200°F (649°C). Excellent resistance to chloride stress-corrosion cracking is another important feature of alloy 800. Alloy 800H is a solution heat treated (2100°F/1150°C), controlled-carbon version of alloy 800 with improved elevated temperature properties. It has improved creep and stress-rupture characteristics in the 1100°F (593°C) to 1800°F (982°C) temperature range.

Spiral Wound Gasket Alloy 800 Applications:
ypical applications for alloy 800 and 800H are - Heat exchangers and process piping; carburizing fixtures and retorts; furnace components; electric range heating-element sheathing; extruded tubing for ethylene and steam methane reforming furnaces; ammonia effluent coolers.
Chemical and petrochemical processing equipments;
Power generation;
Thermal procession fixtures;
Steel production.

Mechanical Properties:
The different anneal temperature used contributed to the difference in strength of the materials.

Corrosion Resistance:
Neither Alloy 800 nor Alloy 304 are suggested for sulfuric acid service except at lower concentrations and temperatures.
Alloy 800 is highly resistant, although not totally immune, to stress corrosion cracking.

Density: 8.03g/cm3

Oxidation Resistance:
The alloys are particularly well suited for high temperature applications such as furnace parts and related heating equipment, for petrochemical reforming units and isocracker tubs, and for handling superheated stem in unclear and conventional power plants. With the specified high levels of chromium and nickel, the alloys offer superior resistance to oxidation and scaling, and to carburization as well.

Welding
The commonly used welding methods work well with this alloy. Matching alloy filler metal should be used. If matching alloy is not available then the nearest alloy richer in the essential chemistry (Ni, Co, Cr, Mo) should be used. All weld beads should be slightly convex. It is not necessary to use preheating. Surface to be welded must be clean and free from oil, paint or crayon marking. The cleaned area should extend at least 2" beyond either side of a welded joint. Gas-Tungsten Arc Welding: DC straight polarity (electrode negative) is recommended. Keep as short an arc length as possible and use care to keep the hot end of filler metal always within the protective atmosphere. Shielded Metal-Arc Welding: Electrodes should be kept in dry storage and if moisture has been picked up the electrodes should be baked at 600 F for one hour to insure dryness. Current settings vary from 60 amps for thin material (0.062" thick) up to 140 amps for material of 1/2" and thicker. It is best to weave the electrode slightly as this alloy weld metal does not tend to spread. Cleaning of slag is done with a wire brush (hand or powered). Complete removal of all slag is very important before successive weld passes and also after final welding. Gas Metal-Arc Welding: Reverse-polarity DC should be used and best results are obtained with the welding gun at 90 degrees to the joint. For Short-Circuiting-Transfer GMAW a typical voltage is 20- 23 with a current of 110-130 amps and a wire feed of 250-275 inches per minute. For Spray-Transfer GMAW voltage of 26 to 33 and current in the range of 175-300 amps with wire feed rate of 200-350 inches per minute are typical. Submerged-Arc Welding: Matching filler metal, the same as for GMAW, should be used. DC current with either reverse or straight polarity may be used. Convex weld beads are preferred.

Cold Working
Cold forming may be done using standard tooling although plain carbon tool steels are not recommended for forming as they tend to produce galling. Soft die materials (bronze, zinc alloys, etc.) minimize galling and produce good finishes, but die life is somewhat short. For long production runs the alloy tool steels ( D-2, D-3) and high-speed steels (T-1, M-2, M-10) give good results especially if hard chromium plated to reduce galling. Tooling should be such as to allow for liberal clearances and radii. Heavy duty lubricants should be used to minimize galling in all forming operations. Bending of sheet or plate through 180 degrees is generally limited to a bend radius of 1 T for material up to 1/8" thick and 2 T for material thicker than 1/8".

Annealing
Annealing after cold work hardening may be required. If so anneal at 1800 F for 15 minutes at temperature and air cool. Do not heat above 1800 F or grain growth will occur with degradation of strength.

Chemical Composition:

C	Mn	P	S	Si	Cr	Ni	Ti	Al	Cu
0.02	1.00	0.02	0.01	0.35	21.0	32.0	0.4	0.4	0.30

Physical Properties

Physical Properties	°F	British Units	°C	Metric Units
Density	Room	0.287 lb./in.(3)	Room	7.95 g/cm(3)
Electrical Resistivity	70 200 400 600 800	38.9 microhm-in. 40.6 microhm-in. 43.0 microhm-in. 44.7 microhm-in. 46.1 microhm-in.	21 93 204 316 427	0.989 microhm-m 1.03 microhm-m 1.09 microhm-m 1.13 microhm-m 1.17 microhm-m
Mean Coefficient of Thermal Expansion	70-200 70-400 70-600 70-800	7.9 microin./in.-°F 8.8 microin./in.-°F 9.0 microin./in.-°F 9.2 microin./in.-°F	21-93 21-204 21-316 21-427	14.2 X 10(-6)m/m-K 15.8 X 10(-6)m/m-K 16.2 X 10(-6)m/m-K 16.6 X 10(-6)m/m-K
Thermal Conductivity	70 200 400 600 800	80 Btu-in/ft²-hr-°F 89 Btu-in/ft²-hr-°F 103 Btu-in/ft²-hr-°F 115 Btu-in/ft²-hr-°F 127 Btu-in/ft²-hr-°F	21 93 204 316 427	11.5 W/m-K 12.8 W/m-K 14.8 W/m-K 16.6 W/m-K 18.3 W/m-K
Dynamic Modulus of Elasticity	Room	28.5 x 10(6) psi	Room	196 GPa

These properties apply to both alloys

Mechanical Properties

Alloy	Form	Condition	Ultimate Tensile Strength, ksi (MPa)	Yield Strength at 0.2% offset, ksi (MPa)	Elongation in 2" or 4D, percent
800	Sheet, Plate	Annealed	85 (586)	40 (276)	43
800	Sheet, Plate Strip, Bar	Annealed	75 (520)*	30 (205)*	30*
800H	Sheet, Plate	SHT	80 (552)	35 (241)	47
800H	Sheet, Plate Strip, Bar	SHT	65 (450)*	25 (170)*	30*

* - minimum
SHT - Solution heat-treated