Q: I have a high temperature application which is exposed to sulfur and chloride gasses. We’re operating at between 1200° and 1400°F. Any suggestions on a bolt material to consider?
A: To deal with both sulfuric/chloride atmospheres as well as high temperatures, you may want to consider Incoloy 800HT bolts or an Inconel 600 bolts depending on the concentrations of the acid gasses. Incoloy is an ideal material for long-term exposure in high temperature environments due to its oxidation, carburization and creep resistance. Incoloy 800 series bolts are all similar and considering your temperature range, I would suggest the Incoloy 800HT since it will not become embrittled even after long periods of usage in the 1200-1600° F. However if you have more severe corrosion issues especially during shut downs or equipment cycling due to acid gasses or condensation formed by the sulfur and chlorine components combining with water, the Inconel fasteners will provide better corrosion resistance than Incoloy.