Study On High-speed Laser Self-melting Welding Of 316L Stainless Steel Sheet

Stainless steel has been widely used in various fields because of its excellent corrosion resistance and satisfying the requirements of low cost in industry.At the same time,thin-walled structure is needed to reduce the weight,reduce the cost,save the resources and realize the maximum utilization of resources,but the thin-walled components are of poor rigidity,so it is easy to cause instability and buckling distortion after welding,which will influence the security of working.Although laser welding is more conducive to reducing the buckling distortion than other methods,it will still be disturbed by large deformation.Under the above conditions,in order to suppress the difficult problems in the laser welding of thin-walled components,this paper sets up a related platform for high-speed laser self-melting welding,including high-speed camera,and completes the experiment and analysis of 0.6mm thick 316L stainless steel sheet.(1)It introduces the development and application fields,main features,two typical welding modes and several main technologies of laser welding,and describes the important achievements of global scholars in laser welding of thin plate materials.And builts the experimental platform equipped with a high-speed camera system for high-speed laser self-melting welding of stainless steel.(2)Through the orthogonal test and the single variable test method,the deformations of high-speed laser self-melting welding of stainless steel sheet are studied and the distortions of the workpiece after welding are measured.The effects of welding speed,laser power,defocus amount and gas flow on diagonal deformation and longitudinal flexure deformation are mainly analyzed,and the relevant improvement strategies are put forward.The sample with very small deformation is obtained by optimizing the process parameters.(3)Through the orthogonal test method,this paper also studies the forming condition of the weld surface of high-speed laser self-melting welding of stainless steel sheet.The effects of welding speed,laser power,defocus amount and gas flow on the weld shape are mainly analyzed.The microhardness measurement and tensile strength test of the joint are carried out,and the related improvement strategies are put forward.The parameters are optimized and the corresponding samples with good shape are obtained.(4)With the help of the high-speed camera shooting system,the relationship between the parameters and the deformation and the weld shape are analyzed from the flow of the molten pool,and the difference when the speed and the amount of the laser power are changed based on the size and the shape of the molten pool.