The creep and breaking strengths of INCLOYOY alloy 800H and 800HT are significantly higher than those of INCOLOY alloy 800. The three alloys have almost the same chemical composition limits. The basic elements in these three alloys are the same. However, chemical composition limits vary for carbon, aluminum, and titanium. Incoloy alloy 800 (UNS NO8800) has a maximum carbon content of 010%, there is no limit to the lower limit. Incoloy alloy 800H (UNS N08810) has a carbon content of 005 ~ 0.10%, is the 0. specified in incoloy alloy 80010% of the maximum cap. The chemical limits of Incoloy 800HT alloy (UNS NO8811) are stricter, but they are still within the limits specified by INCOLOY 800H alloy. The carbon content of the Incoloy 800HT alloy is further limited to 006 - 0.10%。The Al+Ti content of the Incoloy 800HT alloy is limited to 085-1.20%。Please note that the chemical composition of the Incoloy 800HT alloy will always be within the limits of the Incoloy 800H alloy. Also note that the limit of Incoloy Alloy 800H may or may not be within the limit of Incoloy Alloy 800HT.
In addition to controlling the carbon content, Incoloy alloys 800H and 800HT are annealed at high temperatures, resulting in an average grain size of ASTM 5 or coarse. Annealing treatment and restricted chemical composition are the reasons why these alloys have greater creep and breaking strength.
For specific applications, chemical and/or grain size limits may differ from general requirements. For example, some customers have requested that the Al and Ti of the Incoloy 800H alloy be limited to 0 at intermediate use temperatures [1000° to 1400°F (540° to 760°C)].4-0.7%。These special requests are subject to specific order availability.
The mechanical properties of Incoloy alloys 800H and 800HT, combined with their high resistance to wear and temperature corrosion, make these alloys exceptionally suitable for many applications with long-term exposure to high temperatures and corrosive environments. In the hydrocarbon processing industry, these alloys are used in the steam of catalyst tubes, convection tubes, tail braids, outlet manifolds, and quenching system pipes for hydrocarbon reforming; used in ethylene production for convection and cracking pipes, braided pipes; for the production of oxygenols in pipes in hydrogenation heaters; in hydrodealkylation units for heating tubes; and vinyl chloride monomer production for cracked pipes, loopback bends, and inlet and outlet flanges.
Industrial heating is another area where Incoloy 800H and 800HT alloys are widely used. In various types of heat treatment furnaces, these alloys are used in radiant tubes, mufflers, stills, and various stoves. Alloys 800H and 800HT are also used in the generation of steam superheat tubes and high-temperature heat exchangers for gas-cooled nuclear reactors.