Incoloy 800H is an alloy with Cr content usually 15-25%, nickel content 30-45%, and a small amount of aluminum and titanium.

Incoloy 800H has anti-oxidizing medium corrosion, and has good kang carburizing performance at high temperature. Uses: Heat exchanger, steam generator tube, etc. The temperature resistance can reach 1100°C.

INCOLOY 800/800H 

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

UNS Number N08800

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

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. 

In what forms is Incoloy 800H/HT?

Sheet

Plate

 Bar

Pipe & Tube (welded & seamless)

Fittings (i.e. flanges, slip-ons, blinds, weld-necks, lapjoints, long welding necks, socket welds, elbows, tees, stub-ends, returns, caps, crosses, reducers, and pipe nipples)

What are the characteristics of Incoloy 800H/HT?

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

Alloy 800 (UNS N08800) Chemical Composition( %)

Alloy 800H (UNS N08810) Chemical Composition(%)

Alloy 800HT (UNS N08811) Chemical Composition( %)

*Note that the chemical composition of Incoloy 800HT will always be within the limits of Incoloy 800H.

*Note the limits of Incoloy 800H may or may not be within the limits of Incoloy 800HT.

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.

ASTM Specifications

Mechanical Properties

Typical room temperature Tensile Properties of Annealed Material