clamp force or torque for non-steel screws - brass or aluminum

Question

It is common for screw tightening to have the relationship between torque and clamp force defined by:

$$T=kFD$$

However, all the calculators seem to assume the screw is steel. How can this be adjusted if fastener is brass or aluminum? Is it correct to scale results from calculators by youngs modulus. Ref https://www.engineersedge.com/torque.htm

Answer 1

When you read the material in the link it does say you have to make sure the induced stress does not exceed 80% of the yield strength. So establish the yield strength for the material of the screw you are using.