Analysis of the metal-to-metal contact flange joint subject to external bending moment

Abstract

Metal-to-metal contact flange joints are widely used in nuclear and petrochemical industry for severe conditions, because of the relative stability of the sealing gasket stress under complex service condition. In the present work, finite element models were used for analyzing the stress distribution of metal-to-metal contact pipe flange connection under different internal pressures, temperatures, and external bending moments to evaluate the sealing and strength performance. A metal-to-metal contact pipe flange connection device was also experimented. It was found that the results of the axial bolt force and flange hub stress obtained from the experiments were in fairly good agreement with the finite element simulations. The leakage test of metal-to-metal contact type gasket was conducted to highlight its leakage characteristics under different temperatures. The methods to determine the maximum allowable bending moment of a metal-to-metal contact flange joint according the strength criterion and the sealing criterion were analyzed. The results showed that the maximum allowance bending moment was determined by the strength criterion rather than by the sealing criterion with different thermal loadings when the initial bolt-up stress was high enough to achieve metal-to-metal contact contact.

Sealing characteristics of aramid fiber reinforced rubber gasket with scratch depth and width defects

“…The actual joint leakage is thus the net effect of these two competing factors, and therefore, the ability of a gasket to sustain high compressive loads is essential to the control of leakage in a bolted joint. Zhang et al [22] evaluated the sealing and strength performance, finite element models were used for analyzing the stress distribution of metalto-metal contact pipe flange connection, the result showed that the maximum allowance bending moment was determined by the strength criterion. Bouzid et al [23,24] established a leakage model of porous gasket under different medium gases.…”