Abstract
To clarify leakage characteristics of the flat metallic gasket, the leakage rate of a gas and real contact area of the seal surfaces were measured under several closing loads. As the closing loads increased, the leakage flow in the radial direction ceased and only the leakage flow in the circumferential direction remained. To determine the closing load at which the radial leakage flow cease, the real contact situation on the gasket surface should be observed. In this paper the real contact area between the copper gasket and the steel flange was measured using the thin polymer film of 1 μm in thickness. As a result the contact pressure over which the radial leakage ceased could be predicted from the observation of the thin polymer film. In addition, the cross section of the aperture for the leakage flow in the circumferential direction was evaluated from measured real contact area, and the leakage rate was estimated by the assumption of laminar flow. It agreed well with the measured leakage rate.
