ASME STP/PT-029

Description / Abstract: At the present time the ASME Boiler and Pressure vessel code does not include rules for the design of components under external pressure and axial compressive loads in the time-dependent creep regime. A method is suggested in this report for designing components in the time-dependent creep regime. The design methodology is developed for columns and cylindrical shells under axial compression as well as cylindrical, spherical and conical shells under external pressure. An external pressure chart for 2.25Cr-1Mo steel was developed at 1000°F to demonstrate the applicability of the methods developed in this report. In addition, variable factors of safety are imbedded in the design equations in order to transition from the design factors used in the time-independent External Pressure Charts of Section II to the lower design factors specified in Section III for time-dependent, creep buckling.