The Sealing Characteristics of Bolted Flanged Connection With Metal Gasket

Abstract

Metal gaskets have been used in bolted flanged connections under high pressure and high temperature conditions. However, it is difficult to estimate an amount of leakage from the metal contact interfaces in the connections. Recently, it has been noticed that a tiny leakage occurs from the gasket interfaces in bolted flanged connections. Thus, it is necessary to study on the sealing characteristics of the metal to metal contact gasket in the connections under internal pressure and high temperature. In the present paper, for clarifying the characteristic of the metal gaskets, some experiments were conducted at room temperature. The gaskets are used aluminum, copper and mild steel flat gaskets. Firstly, according to JIS B 2490, the sealing behavior was measured taking account the surface roughness of the metal gaskets. The gaskets were compressed using a material testing machine while the amount of leakage was measured. Secondly, the amount of leakage was measured for bolted flanged connections with metal gaskets. The flange nominal diameter used was 2″. Finally, the contact gasket stress distributions in the connection were analyzed using 3-D FEM analysis. Using these results, discussion was made on the sealing behavior of the metal gaskets. In the result, it is found that plastic strain is important for the sealing performance of the metal gasket.