UNS Number N08800/N08810/N08811

Incoloy 800, 800H, and 800HT are nickel-iron-chromium alloys with good strength and excellent resistance to oxidation and carburization in high-temperature exposure. These nickel steel alloys are identical except for the higher level of carbon in alloy 800H, and the addition of up to 1.20 percent aluminum and titanium in alloy 800HT. Incoloy 800 was the first of these alloys and it was slightly modified into Incoloy 800H. This modification was to control carbon (.05-.10%) and grain size to optimize stress rupture properties. Incoloy 800HT has further modifications to the combined titanium and aluminum levels (.85-1.20%) to ensure optimum high temperature properties. The nickel alloy is dual certified (800H/HT) and combines the properties of both forms. Incoloy 800H/HT alloy was intended for high temperature structural applications. The nickel content makes the alloys highly resistant to both chloride stress-corrosion cracking and to embrittlement from precipitation of sigma phase. The general corrosion resistance is excellent. In the solution annealed condition, alloys 800H and 800HT have superior creep and stress rupture properties.

Available Forms of Incoloy 800/800H/800HT at Rooplaxmi Steels:

•           Bar
•           Sheet
•           Plate
•           Pipe & Tube (welded and seamless)
•           Pipe Fittings
•           Wire

Characteristics of Incoloy 800/800H/800HT:

•           High temperature strength
•           High creep rupture strength
•           Resistant to oxidation and carburization in high temperature environments
•           Good corrosion resistance in many acidic environments
•           Good resistance to many sulfur-containing atmospheres

Incoloy 800 Chemical Composition, %:

Ni	Cr	Fe	C	Al	TI	Al+Ti
30.0-35.0	19.0-23.0	39.5 min	0.10 max	0.15-0.60	0.15-0.60	0.30-1.20

 

Incoloy 800H Chemical Composition, %:

Ni	Cr	Fe	C	Al	TI	Al+Ti
30.0-35.0	19.0-23.0	39.5 min	0.05-0.10	0.15-0.60	0.15-0.60	0.30-1.20

 

Incoloy 800HT Chemical Composition, %:

Ni	Cr	Fe	C	Al	TI	Al+Ti
30.0-35.0	19.0-23.0	39.5 min	0.06-0.10	0.25-0.60	0.25-0.60	0.85-1.20

 

Application of Incoloy 800/800H/800HT:

•           Ethylene furnace quench boilers
•           Hydrocarbon cracking
•           Valves, fittings and other components exposed to corrosive attack from 1100-1800° F
•           Industrial furnaces
•           Heat-treating equipment
•           Chemical and petrochemical processing
•           Super-heater and re-heaters in power plants
•           Pressure vessels
•           Heat exchangers

Machining and Fabrication with Incoloy 800:

Machining characteristics of this Incoloy alloy 800 are similar to that of iron-based alloys. This alloy tends to work-harden during machining. It can be welded by common welding techniques, using a matching filler metal. It can be hot worked at temperature ranges of 871-1232°C (1600-2250°F). Cold working may be done on the alloy using standard tooling. 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.

Incoloy 800/800H/800HT ASTM Specification:

Pipe Smls	Pipe Welded	Tube Smls	Tube Welded	Sheet / Plate	Bar	Forging	Fitting
B407	B154	B163	B515	B409	B408	B564	B366

Mechanical Properties of Incoloy 800/800H/800HT:
Typical room temperature Tensile Properties of Annealed Material

Product Form	Tensile Min. (ksi)	0.2% Yield Min. (ksi)	Elongation %
Rod & Bar	75-100	30-60	60-30