Behavior of Flange Joints Under Combined Internal Pressure and Thermal Loading: The Case of Using Metal-to-Metal Contact Type Gaskets

Abstract

In a bolted flange joint, metal-to-metal contact type gasket takes over only part of the bolt load to achieve seating stress, and the additional bolt load is transmitted to the metal-to-metal contact to compensate for the unloading effects due to internal and external loadings. Due to this advantage, flange joints with metal-to-metal contact type gaskets are gradually used in chemical industry, nuclear power industry, etc. A three-dimensional nonlinear finite element model is developed to highlight the complex behavior of the flange joint with metal-to-metal contact type gasket under combined internal pressure and thermal loading. Despite of the common perception that the gasket stress in the metal-to-metal contact type gasket stays constant, reduced gasket stress is concluded due to flange rotation and joint thermal expansion.