Exposing PEEK Screws to HCl

Q: What is the max temperature I could expose PEEK screws to HCl?

A: This depends on the concentration of the HCl but if you were at about 15%, the PEEK fasteners can be exposed to about 100C of hydrochloric acid solution. See this chart https://www.extreme-bolt.com/peek-fasteners-flanges.html#Chemical. That is the max temperature/concentration at which the PEEK screws will retain their strength and chemical composition at 15% concentration.However lower the concentration the higher the temperature you could go and vise versa.