Alloy 800H/HT^®

Documentation:

CMI Alloy Data Sheet 

Description:

Alloy 800H/HT^® is an iron-nickel-chromium alloy having the same basic composition as Alloy 800 but with significantly higher creep rupture strength. The higher strength results from close control of carbon, aluminum and titanium contents in conjunction with a high temp anneal. The 800H modification was to control carbon (0.05 to 0.10%) and grain size to (>ASTM 5) to optimize stress rupture properties. Alloy 800H/HT^® (UNS N08811) has further modifications to combine titanium and aluminum levels (0.85 to 1.2%) to ensure optimum high temperature properties. The alloy is dual certified and combines the properties of both forms. The chemical balance allows the alloy to exhibit excellent resistance to carburization, oxidation and nitriding atmospheres. Alloy 800H/HT^® will not become embrittled even after long periods of usage in the 1200-1600 degF range where many stainless steels become brittle. Excellent cold forming characteristics typically associated with the nickel-chromium alloys are exhibited with 800 H. When cold formed extensively the grain size produces a visibly undulated surface called "orange peel". Alloy 800H/HT ^® can be welded by the common techniques used on stainless steels. Typical applications for the alloy include ethylene pyrolysis, hydrocarbon cracking, cracking furnaces for vinyl chloride, diphenol and acetic acid. The alloy is also used for valves, fittings and other components exposed to corrosive attack from 1100 to 1800 deg F. Corrosion Materials maintains an inventory of round bar ranging from 3/4" to 6" diameter and pipe from 3/4"-8". Material can be supplied in random lengths, cut to order or machined to customer requirements. Machining includes drilling, threading, milling, CNC shapes, turning, tapping, flanges and others. 800HT^® is a registered trademark of Special Metals Company.

Chemical Composition: