High temperature usually have an adverse effect on the performance of the gasket joint.Such as high temperature can make the gasket mechanical properties including tensile strength, resilience rate (modulus) and carrying capacity degradation occurs, as most rubber bonded asbestos or non asbestos fiber materials (except flexible graphite) will happen in the high temperature decomposition, pulverization, or permanent deformation, its highest use pressure decreased with increasing temperature.
Secondly, the high temperature creep or relaxation of gasket strengthening effect is obvious, for example, under the same load, asbestos rubber gasket 3.5 times that of the relaxation at room temperature of 200 ℃.But instead of flexible graphite asbestos gaskets in oxidizing medium continuous working temperature also should consider to less than 343 ℃.Thermal expansion or contraction of gasket changed the gasket stress, thus its sealing ability also change accordingly.
In addition, the thermal fluctuations or thermal cycling in joint can cause joint gasket ratchetting deformation ratchet and stress, and this effect depends on the viscoplastic gasket and the nonlinear response of stress and strain and temperature and other factors.