Q: I need a material that offers about 80-90ksi yield but is also corrosion resistant to low concentrations of sulfur acid. I’m tried 17-4Ph but its not working? Any ideas.
A: Yes, 17-4PH fasteners are excellent for high strength like you need, but are not really geared for corrosion resistance in acids. For this situations, I would suggest Inconel 625 bolts. If offers about 84ksi yield strength and 144ksi UTS. It also offers good resistance to many corrosive environments including sulfuric acid. If more strength is needed you may want to try Incoloy 925 or Inconel 718. Both do when in corrosive situations and offer will over 100ksi yield strength.