Q: I have an application with high temperature exhaust that requires a high strength bolt for oxidation resistance. Temps are pretty consistent around 1300F. Would Inconel 718 bolts be a good choice?

A: Inconel 718 would definitely be one good option. Inconel 718 bolts offer 210ksi tensile strength and are used up to about 1300F. If you can accept a bit lower strength another material to consider would be Nimonic. Nimonic 80A fasteners offer a strength of 181ksi tensile and has a max usable temperature of 1500F with excellent oxidation resistance. Finally another very strong alloy for high temperature oxidation resistance is A286. A286 bolts will get you a typical tensile strength of 130ksi (cold worked a min of 160ksi) and does well in high temperature environments.

Q: I have require fasteners for use in an annealing oven for aa centrifugal fan (@1725 RPM) attached to a shaft with a through bolt and nut (shaft and fan are both SST). The environment is 1275 degrees F at atmospheric pressure and runs continuously 5 days a week I require fasteners that will have a long service life, but easily removable for maintenance. Ideas?

A: For a high temperature application such as this, you might want to consider A286 bolts and nuts. A286 is a high temperature stable and very strong steel.  Often used in high temperature turbines and exhaust applications, these bolts will retain their strength to 1300°F .

If you combine this with our Moly-Disulphide anti seize (if that is OK in your application) you will have no problem getting them off. .

Q: I need a shoulder bolt that will not change its shape at elevated temperatures. The bolt is near a mild carbon steel welding process and is under a small load. It is not in the heat affected zone, but it does see an elevated temperature. I am not sure exactly, but if we assume it sees 80% of the A 36 melting temperature, then we should be conservative. Any suggestions appreciated.

A:  For elevated temperatures I would recommend an A-286 shoulder bolt. A-286 fasteners are known for their high strength, creep resistance and oxidation resistance at elevated temperatures. This material would be a significant improvement over carbon steel. A286 bolts will retain their strength to 1300°F .