We are looking at using Hastelloy bolts for service in our concentrated HCl facilty (33%). Which type of Hastelloy is best for corrosion resistance at ambient temperature up to 50 degrees Celcius?
I'll suggest you contact either Special Metals Corporation or Haynes International. Both have websites and contact forms. And, both have knowledgeable personnel in the corrosion fields with experience dealing with the Hastelloy family.