Thread analysis

[davidlee97]

When I work on an report that needs to analyze a threaded part on valve, may I use 3XSm to be allowable stress intensity as ASME VIII Div2 described? The part connects with body by thread (UNF) and preloaded torque to press another component to withstand internal pressure. What I am hesitate is the part has hollow round hole. So that it looks like cylinder with external thread rather than solid as a bolt. I calculated Von Mises stress with axial and stress stress caused by torque, then I need to compare with allowable stress.

Thanks!