Incoloy 800, 800H, and 800HT properties 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. 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. Standard Inventory Specifications ASTM B 409, ASTM B 408,
ASTM B 407, ASTM B 564 UNS N08810, UNS N08811 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. Incoloy 800, 800H, and 800HT Specifications Incoloy 800, 800H, and 800HT Mechanical Properties Typical room temperature Tensile Properties of Annealed Material In what forms is Incoloy® 800H/HT available at DZ ? - 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)
- Wire
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
|