| The large scale natural gas storage spherical tank made of thick plate welding is widely applied in petrochemical industry.The welding process is characterized by long welding seam,large welding area and complex welding surface.The traditional manufacturing method of this kind of spherical tank is manual welding.It has the disadvantages of low efficiency,high labor intensity and high cost.At the same time,it is difficult to ensure the stability of welding quality.At present,some enterprises use the arc welding robot teaching programming method to make spherical tank welding.It still has the problems of low efficiency and difficult to adapt to the complex space weld.At the same time,the ideal welding gun position and position can not be guaranteed.Therefore,it is urgent to develop the off-line programming technology and equipment with automatic planning of welding parameters,automatic planning and Simulation of multi-layer and multi-channel welding paths to speed up the construction speed,reduce labor intensity and improve the quality of welding,and then improve the international competitiveness of China's spherical tank welding manufacturing industry.Taking the five thousand cubic meters natural balloon tank as an example,based on the basic laboratory conditions,the thirty millimeter thick Q370 R steel plate is used as the simulated spherical tank test plate,and the off-line programming technology for multi-layer and multi-channel automatic welding process parameters planning,path planning and simulation analysis is carried out.The key technology of automatic welding is summarized through the analysis of all position welding robot of three kinds of orbit,rail,and intelligent spherical tank.The key technology of automatic welding is off-line programming.The off-line programming mainly includes the planning of process parameters,path planning and simulation.Solving these key technologies will lay a solid foundation for the automatic welding of spherical tanks.Based on the carbon equivalent method,the weldability of Q370 R thick plate is analyzed.Through the analysis of the chemical composition and mechanical properties of the GCR-81Ni1 MP metal cored wire,the experimental study on the diffusion hydrogen,the stability of the arc,the efficiency of the cladding and the spatter rate of the wire shows that the GCR-81Ni1 MP welding wire can be used for automatic welding of the thick Q370 R plate.The test of the butt crack in the sloping y slope,the maximum hardness test of the heat affected zone and the SHCCT determination proved that the abnormal microstructure andcrack will not appear in the Q370 R thick plate under the automatic welding process of the gas shielded flux cored wire.The optimum welding parameters of different welding positions are obtained by several tests.The rationality of welding process is verified by the tensile,impact,bending and hardness tests of the welded joint.Through the MAG welding test of arc welding robot,the relationship between welding parameters and the influence of welding width and residual height are studied,and the influence of welding parameters on the weld formation is obtained.The fusion welding forming model is studied by BP neural network.The four-ten-two model of BP neural network,which takes the wire feeding speed,the welding speed,the length of the wire and the gas flow as the input variable,the weld pool width and the residual height as the output variable,is trained and tested,and the welding process is realized.Parameters are used to predict the shape and size parameters of the weld.According to the influence of the welding parameters on the weld shape,a function relation between the cross section of the weld and the speed of wire feeding and welding speed is established,and the planning of the welding process parameters is realized.By means of the equal section method,a multi-layer and multi-channel pass welding path planning for double-sided V-groove workpiece is carried out,and the layout rule of thick plate multi-layer and multi-channel pass welding is established.According to the D-H parameter method,a welding robot model is established in MATLAB,and the welding path is simulated and analyzed,which verifies the rationality of the welding path planning.Through the RobotArt off-line programming software,the three-dimensional model of the workpiece and robot is established.According to the analysis of the position and posture of the weld in the groove,the trajectory planning and simulation analysis of the workpiece are carried out by using the optimization rule of the welding process parameters and the multi-layer and multi-channel arrangement law of the thick plate.Then the program is processed after the process and the program is introduced into the program.The robot control cabinet directs the robot to carry out automatic welding test to the workpiece,verifies the feasibility of the program and realizes the multi-channel and multi-channel automatic welding of the spherical tank with Q370 R thick plate.The research work is of great significance for automatization,improving efficiency and reducing cost of robot spherical tank welding. |
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