Research On Performance And Process Parameters Of Flexible Graphite Metallic Spiral Wound Gasket

Flexible graphite metallic spiral wound gasket(here in after referred to as SWG)is formed by alternately winding a metal wound tape(usually V-shaped or W-shaped)of a certain shape and size with a flexible graphite filling material,and it's widely used in petrochemical,nuclear power,ship and other process industries due to its simple structure and excellent sealing performance.At present,the research on the process parameters of SWGs is not deep enough at home,and the test standards are still not perfect,still uses 70 MPa as the test stress,resulting in the classification of SWGs is not clear.Although some gasket performance can meet the test standard requirements,in actual use,there will still be problems such as insufficient compression or crushing,resulting in seal failure.In this paper,for the SWGs with inner and outer ring,which are widely used in the process industry,are combined with experimental and finite element simulation analysis to research the influence of process parameters on its performance.The main tasks as follows:Firstly,select the winding density,the top pressure and the positioning ring as the main process parameters of the SWGs.The standard test sample are prepared according to the determined process parameters,and the compression-resilience test is carried out.The results show that with the winding density and the top pressure increases,the compression performance of the gasket decreases,and the resilience performance increases.As the installation size of the positioning ring increases,the compression performance of the gasket increases,and the resilience performance decreases.Secondly,the commercial finite element software ABAQUS is used to establish the two-dimensional axisymmetric finite element model of SWG,and the nonlinear Elastic-Plastic analysis of the compression resilience process is carried out.The results show that the compression-resilience curve obtained by numerical simulation is basically the same as the test curve.However,due to the complex internal deformation and stress during the compression process of the gasket,the simulation results are still deviated from the experimental results.Finally,the sealing performance test of SWGs under different process parameters was carried out using AMTEC TEMESfl.ai1 gasket comprehensive performance testing rig.The results show that at the same stress level,the leakage rate of the gasket decreases with the increase of the winding density and the top pressure,and decreases with the decrease of the installation size of the positioning ring.The research results have important engineering value and practical significance for optimizing the graded manufacturing of SWGs,improving sealing performance and guiding the rational selection of SWGs.