Research And Design Of The Working Table For The Inner Wall Of 90°Elbow

The 90° elbow structure is widely used in metallurgy,mining and other industries,especially in the corrosive environment.The double metal composite bend pipe,cladding of the valve wall,has been adopted to prevent the bend pipe from being badly damaged,such as hydrogen embrittlement,hydrogen corrosion,hydrogen sulfide corrosion and the surfacing layer exfoliation.At present,there are two commonly used methods.One is to weld the straight pipe first and then bent it into a bend pipe.The other is to use the specific welding machine to weld the valve wall of the bend directly.With the increasing demand of 90° bend pipe,new requirements of its manufacturing technologies and processes are put forward.Therefore,it is of great applied value to study the surfacing technology and surfacing workbench of 90° elbow valve wall.The thesis completes the following research work:Firstly,the principle and method of surfacing welding on the inner wall of the 90°elbow were studied.According to the existing methods of longitudinal and annular surfacing welding,a new horizontal fan-shaped surfacing welding method for elbow is proposed.Combining the principle of displacement in the relevant field of surfacing workbench,a new multi-degree-of-freedom,adjustable 90° elbow inner wall surfacing workbench was designed,which can be used in conjunction with welding robots to complete a variety of 90° elbows at one time.There are three rotation degrees of freedom in the space,a rotation center adjusting the mechanism up and down,and a multi-functional adjustment fixture,achieving a one-time surfacing welding of the nominal diameter 250mm~400mm elbow.Secondly,according to the design of the 90° elbow inner wall surfacing workbench,the overall structural scheme,power source,transmission system and the adjustment fixture system are designed in details,and the relative motion parameters and size parameters of the workbench are determined.The virtual prototype of the inner wall surfacing worktable of 90° elbow is built by using UG.The surfacing process of the 90°elbow surfacing was simulated and verified.The performance of the bench was verified,and technical support was provided for the design of the manipulator.Finally,ANSYS Workbench software was used to perform finite element analysis on the workbench to obtain stress and strain cloud diagrams,check the stiffness and strength of the workbench,and verify the practical performance of the workbench;perform modal analysis to obtain the modal shape diagram,analyze the vibration characteristics,and understand more detailed of the mechanical performance of the workbench;do the optimization design to the structure by using the analysis results of the finite element,and provide the theoretical support for the future experimental prototype manufacturing.