Q: I need a material that will be suitable for oil and gas use. Submersion in hydrogen sulfide, carbon dioxide, hydrocarbons, salt water at temperatures up to 325F. Crevice corrosion has been a factor. Also need 170ksi min tensile strength. Plus we’d like to torque a 3/8-24 fastener to 50 ft lbs.

Sound like a good applications for Inconel 718 bolts.  This material has a min ultimate tensile of 180 ksi and typically well into the 200+ range. Because its high nickel content it will do well in sour gas/corrosive environments and is often chosen for down hole oil projects. It is resistant to a  wide ranges of acidity and alkalinity, including sulfur compounds and chloride environments.

With regards to torque, the value that is required is 100% dependent on the material, so you should not have a pre-determined torque value.  With that said the torque for an Inconel 718 bolt 3/8-24 could range from around 50-67+ Ft-Lb, depending on a variety of factors such as: Lubrication, condition of bolt or mating fastener, cleanliness etc. This is a general range but the actual torque could vary significantly depending on the actual bolt conditions.