In Reply to: Re: Torque Value Hydraulic Pump Bolts posted by Tim Daley(MI) on November 21, 2019 at 14:27:28:
"First, torque is calculated by fastener size and material, not the material it is fastened to or with."
Fastener tightening torque is properly calculated using the yield strengths of the material used for BOTH the male AND female parts as well as length of thread engagement. The reason for that should be obvious. Here is a good engineering calculator for doing that - note the number and types of inputs required:
Fastener Torque Calculator
Formulas that use only bolt diameter and material are general purpose approximations and assume a lot. Using them in a situation to which they don't apply (e.g. 160 KSI steel bolt screwed into 40 KSI aluminum) is a recipe for thread failure.