Incoloy 800H

ASTM B 409, B 408, B 407, B 564

UNS Number N08810/N08811

Other common names: Alloy 800, Alloy 800H/HT

ncoloy 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. Today, most suppliers, including Mega Mex, only carry the dual certified 800H/HT alloy.

Incoloy 800 is primarily used in applications with temperatures up to 1100° F, where alloys 800H and 800HT are normally used in temperatures above 1100° F where resistance to creep and rupture is required. The chemical balance allows the nickel steel alloy to exhibit excellent resistance to carburization, oxidation and nitriding atmospheres. Incoloy 800HT will not become embrittled even after long periods of usage in the 1200-1600° F range where many stainless steels become brittle. Excellent cold forming characteristics typically associated with the nickel-chromium alloys are exhibited with 800HT. When cold formed extensively the grain size produces a visibly undulated surface called “orange peel”. Incoloy 800HT can be welded by the common techniques used on stainless steels.

Alloy 800 Chemical Composition, %:

Alloy	%	Ni	Cr	Fe	C	Mn	Si	Cu	S	Al	Ti
800	Min.	30	19							0.15	0.15
	Max.	35	23	balance	0.10	1.5	1	0.75	0.015	0.60	0.60
800H	Min.	30	19		0.05					0.15	0.15
	Max.	35	23	balance	0.10	1.5	1	0.75	0.015	0.60	0.60
800HT	Min.	30	19		0.06					0.15	0.15
	Max.	35	23	balance	0.10	1.5	1	0.75	0.015	0.60	0.60
	AI+Ti: 0.85-1.20

Incoloy 800H Physical properties

Density	8.0 g/cm³
Melting point	1350-1400 ℃

Incoloy 800H Alloy minimum mechanical properties in the room temperature

Alloy	Tensile strength Rm N/mm²	Yield strength R P 0. 2N/mm²	Elongation A 5 %
800	500	210	35
800H	450	180	35

800H Characteristic as below:

• Excellent corrosion resistance in the water media of the extremely high temperature of 500℃.
• Good stress corrosion resistance
• Good machining

Heat exchanger with Alloy
800H/800HT Components

In what applications is Incoloy 800H/HT used?

• 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

Alloys 800H/HT are used in a variety of applications involving exposure to corrosive environments and high temperatures such as heat treating equipment, chemical and petrochemical processing, nuclear power plants and the paper pulp industry. Heat-treating equipment such as baskets, trays, and fixtures employ Incoloy 800H/HT. Chemical and petrochemical processing industries use the alloys for heat exchangers and other piping systems in nitric acid media especially where resistance to chloride stress-corrosion cracking is required. Power plants use them for super-heater and re-heater tubing.

For information on machining, click here.

Incoloy 800H Metallurgical structure:

800H is the face-centered cubic lattice structure, very low carbon content and increased Ti:C rate improve the stability of the structure, anti-allergy, and anti-intergranular corrosion. Low temperature annealing around 950℃ ensure the fine grain structure.

Incoloy 800H Corrosion resistance:

800H can not be corroded in many kinds of media. Its higher nickel content made it have good stress corrosion resistance cracking properties in the water corrosion condition. High chromium content made it better resistance to pitting and crevice corrosion cracking. This alloy can resist nitric acid and organic acid, but it is not so fine in the sulfuric acid and hydrochloric acid.

800H have good corrosion resistance to both oxidation and non-oxidizing salt, but maybe a little pitting in halide, and also excellent properties in the mixture of water, smoke, steam, air and carbon dioxide.

For the application of up to 500℃ environment, alloy state supplies change to annealing.

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MONEL ®alloys MONEL®Monel 400 MONEL®alloy K-500 Inconel®alloys Inconel 600 Inconel 601 Inconel 625 Inconel 718 Inconel X-750

INCOLOY®alloys Incoloy 800H Incoloy 800HT Incoloy 825 Incoloy 901 Incoloy 926 Inconel 600 Inconel 601

Hastelloy®alloys Hastelloy B Hastelloy B-2 Hastelloy C-4 Hastelloy C-22 Hastelloy C-276 Hastelloy N10675

Other alloys A-286 254SMO Nimonic 80A Invar alloy 904L Duplex S31803

Available forms are seamless pipe, welded pipe, seamless tube, welded tube, bar, wire, sheet, plate, forgings, pipe fittings and flanges..

Products	Standard
Sheet/Plate content	ASTM B443, AMS 5599, AMS 5869, ISO 6208, VdTüV 499, BS 3072NA21, EN 10095, DIN 17750
Round Bar/Wire content	ASTM B446, AMS 5666, AMS 5837, ISO 9723, ISO 9724, ISO 9725, VdTüV 499, BS3076NA21, EN 10095, DIN 17752, DIN 17753, DIN 17754
Pipe & Tube content	ASTM B444, ASTM B751, ASTM B829, ASTM B775, ASTM B705, ASTM B704, AMS 5581, ISO 6207, VdTüV 499, BS 3074NA21, DIN 17751
Fittings content	ASTM B366
Forgings content	ASTM B564, AMS 5666
Weld Wire content	AWS A5.14 ERNiCrMo-3, AWS A5.11 ENiCrMo-3, DIN 1736 SG NiCr20Mo9Nb