Post-weld heat treatment (PWHT) is the broader term. Stress relief is one type of PWHT, done below lower critical temperature. Other PWHTs: solution annealing (for stainless), tempering, normalizing.
How to calculate it based on fluid properties and service life. static equipment interview questions
: What loads must be considered? These include internal/external pressure, weight of the vessel, superimposed static loads from other equipment, and environmental loads like wind and seismic forces. Post-weld heat treatment (PWHT) is the broader term