The Analysis of Bolted Flange Joints under Internal Pressure at High Temperature

Working temperature, internal pressure and the creep of bolted flange joints are the direct factors that influencing the gasket stress of bolted flange joints, the tightness of the whole system will be reduced because of these factors. thus the security level of bolted flange connection will be affected. In this paper, the deformation coordination equation of bolted flange connection system, the gasket compressive and resilient performance, as well as the gasket creep equation are combined to study the effect of internal pressure on bolted flange connections under a certain bolt preload and operating temperature, the equation about the relationship of the gasket force and internal pressure is simplified, and the main objective of the work is the calculation of the time-correlated gasket force, flange rotation and gasket unloading deformation under the different internal pressure. The results show that when the internal pressure is greater, the gasket force is smaller, on the contrary, the leakage rate are greater. Through the relevant conditions, in a period of the safe operation time, the maximum working internal pressure is got when reaching the condition of corresponding level of tightness.