Pipe flange connections with asbestos gasket and non-asbestos gasket subjected to internal pressure at room temperature are analyzed taking account of a hysteresis in stress-strain curve of the gasket using axisymmetric theory of elasticity and a three dimensional finite element method (FEM) . The contact gasket stress distributions, the hub stresses and the variations in axial bolt force are examined in each pipe flange connection with asbestos and non-asbestos gaskets. The characteristics of the connections are demonstrated between asbestos and non-asbestos gaskets. Moreover, the amount of leakage is estimated using the basic gasket property obtained from JIS B 2490 and the contact gasket stresses obtained from the axisymmetric theory of elasticity and FEM. The estimated results are compared with the experimental results obtained from the leakage tests, where the compressed sheet gaskets (CSG) are used. It is found that the differences in the contact gasket stress distributions between pipe flange connections with asbestos and non-asbestos gaskets are small. The sealing performance of the pipe flange connections with non-asbestos gasket is equivalent to that with asbestos gasket at room temperature.

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Stud joints of C6191 aluminum bronze were friction welded and its joint strength was examined. A hardened stir zone formed at the weld interface and its width increased with a friction time. In the tensile testing, since all friction welded joints fractured in the plate side, friction weldability of C6191 stud joints was good. Contrary, arc stud welded joints fractured at the weld zone and there were blowholes. In the bending testing, friction welded joints were fractured near the weld zone at bending angle of about 5°. In the fatigue testing, friction welded joints fractured near the weld zone and the fatigue limits of joints were 90-115MPa.

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