Internal Spinning Forming And Interfacial Bonding Properties Of TA2/20 Bimetallic Pipe

In recent years,bimetallic pipes with excellent comprehensive performance have been widely applied in petrochemical,marine development,aerospace and other areas.At present,there are many forming processes for forming bimetallic pipes,but various forming processes has certain scope of application.As a new type of flexible pipe forming process,the internal spinning forming process has the characteristics of flexible processes,high material utilization,low production cost,high production efficiency and high forming accuracy,it has a wide application prospect in the field of bimetallic pipes forming.In the process of internal spinning forming,different process parameters have different effects on the forming quality of bimetallic pipes.If the process parameters are not reasonably controlled,there will be defects such as excessive thinning of wall thickness,poor forming quality and poor interfacial bonding properties.At present,there is little research on the internal spinning forming process of bimetallic pipes,so it is necessary to explore the internal spinning forming process of bimetallic pipes.In this study,the internal spinning forming process of TA2/20 bimetallic pipe was studied by means of theoretical analysis,finite element simulation,and forming experiments,it provides guidance for the practical application of bimetallic pipes internal spinning process.The main content and conclusions of this article were as follows:(1)Based on the theory of elastoplastic mechanics,the stress-strain states of the outer pipe and the liner pipe during the loading stage and the unloading stage were analyzed,and the variation law between radial spinning pressure and residual contact stress was obtained;Based on the?O2O?leucku? rotary pressure calculation method,the effect of process parameters on the residual contact stress between the outer pipe and the liner pipe was studied,and the variation law between process parameters and residual contact stress was obtained.(2)According to the internal spinning forming process of TA2/20 bimetallic pipe,the reasonable forming scheme and process parameters were established.In addition,the internal spinning forming tools were designed,it laid the foundation for the follow-up finite element simulation and forming experiments of TA2/20 bimetallic pipe.(3)The finite element simulation model of internal spinning forming of TA2/20 bimetallic pipe was established,the stress and strain,the wall thickness distribution,and the residual contact stress distribution between the liner pipe and the outer pipe after forming were analyzed,and the change rules in different stages of the internal spinning process were obtained.Furthermore,the stresses in three directions of the bimetallic pipe were comparatively analyzed,and the order of the three-dimensional force between the liner pipe and the outer pipe after forming was obtained.In addition,the effects of the roll feed ratio,the embedding amount,and the initial gap on the wall thickness difference of the liner pipe and the residual contact stress were studied,the influences of different process parameters on the wall thickness difference of the liner pipe and the residual contact stress were obtained.(4)The effects of different process parameters on the wall thickness difference of the liner pipe and the residual contact stress were studied by conducting forming experiments,the results of which showed that with the increase of process parameters,the wall thickness difference of the liner pipe decreased at first and then increased,the residual contact stress increased at first and then decreased;The change trend of the experimental results of residual contact stress was consistent with the finite element simulation and theoretical analysis,this effectively verified the reliability of the finite element simulation and theoretical analysis.Moreover,the change of the microstructure of TA2/20 bimetallic pipe before and after forming was comparatively analyzed,and the change rule of the microstructure of bimetallic pipe was obtained.In addition,putting the solder paste between the liner pipe and the outer pipe could obtain TA2/20 bimetallic pipe with a bonding strength of 10.766 MPa.