Q: Perhaps you can help. I am looking for a stainless-steel substitute to replace a standard SHCS. I will be fastening a stack of hydraulic valves onto a 6061-aluminum manifold with a 3000 PSI working pressure. I am not sure what the tensile strength needs to be comparable to a carbon steel screw.
A: A material you should consider would be a 17-4PH socket head cap screw. This material could be tailored to various strengths by adjusting the heat treatments. As there are many kinds of carbon steel available, it’s difficult for us to suggest a strength that would be comparable, however if we ASSUME a Grade 8 bolt, this will have a min 150ksi tensile. Therefore, a 17-4 PH heat treatment of 1075 or better should do the trick.
The following link will show you some of the 17-4PH heat treatment options available.