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 nit riding 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
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
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 exchanges 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.