Q: We have on application that utilizes an HCl tank and are currently using hastelloy C276 bolts but they are not sufficient. Should we try tantalum fasteners or anther material like PEEK? The bolts are for a flanged valves connections concentration is 36%, temperature 45ºC.
A: Though the HCl is not at a high temperature, I would suggest Tantalum bolts or possible Zirconium bolts. I would not recommend polymer fasteners for a flanged connection unless your sure the load is very low. Follow the link to the blog we wrote specifically on this problem. If your acid is clean, Zirconium could be a good choice.