The influence of the mechanical properties of copper at elevated temperatures on the tightness of the sealing joint

Abstract

The sealing joint is presented as the contact of a rigid rough surface with an elastoplastic half-space with the properties of C11000 copper at normal and elevated temperatures. To describe the elastoplastic hardened material, the Hollomon power law is used. The parameters of the true stress–strain curves at elevated temperatures are determined from the reference data of the conditional tensile diagram: yield strength, tensile strength, modulus of elasticity and residual deformation of 0.2% at the yield strength. A rigid rough surface is represented as a set of identical spherical segments, the distribution of which in height corresponds to the reference profile curve of the real surface. The relative contact area, the density of the gaps in the joint, and the permeability functional are determined depending on the dimensionless load for different temperatures according to methods previously developed by the authors. A method for calculating the amount of leakage through the sealing joint of the valves of the pipe fittings and pressure vessels depending on the contact characteristics, the probability of the medium flow and the properties of real gas is proposed. To accurately describe the real properties of technically important gases in a wide range of pressures and temperatures, the virial equation of state is used.