Research On Robotic Welding Process Of Large-scale Structural Parts With Complex Welding Seams

Steel structure usually has many welding seams and complex structure.Predicting and controlling welding deformation is an effective means to optimize welding process.Improving technology level can improve product quality.At present,there are some research results in this field at home and abroad,but for complex large-scale welded structural parts,there are few application cases to optimize the welding process.In this paper,the welding simulation and prediction,welding quality control and robotic welding applications are studied.The emphasis is to optimize the welding process with triangular welding frame as an example,and summarize the prediction and control methods of welding deformation,so as to provide technical support for the process design and optimization of the launcher.The main contents of this paper are as follows:Firstly,the related research background is introduced,the current research status of deformation prediction and welding simulation is summarized,and the basic theory of welding numerical simulation technology is discussed,including welding temperature field theory,welding THERMOELASTIC-PLASTIC theory,and the characteristics of heat source model involved in simulation are briefly analyzed.Then,according to the welding structure,the potential influencing factors of welding deformation are analyzed,and the corresponding deformation control methods and solutions are put forward according to the difficulties.Through orthogonal experimental design,the welding parameters are selected to study the influence of different parameters on welding deformation.The reliability of welding is verified by tensile test.Finally,the parameters are determined by combining orthogonal experimental results and weld strength,which provides experimental basis for controlling deformation and welding quality.Then,according to the shape and size of heat affected zone of weld cross section,the parameters of double ellipsoid heat source model and heat cycle curve are modified to provide two kinds of heat sources for welding simulation,and the heat cycle curve method is extended to check the temperature field of multi-layer and multi-pass welding.Through comparison,it is found that the calculation efficiency of heat cycle curve method is obviously higher than that of heat source model method.Finally,the welding process of the triangle frame is simulated,the dynamic deformation law of the main deformation points is studied,and the influence of different welding seams on the deformation is analyzed.Based on this,the welding process optimization is carried out.By comparison,the better welding process is applied to the actual welding experiment of the triangle frame.The results are compared with the simulated deformation,which proves that the simulation of welding process optimization has the corresponding characteristics.Use reliability.It has important guiding significance for production to optimize the process of other parts of launcher and realize the optimization and adjustment of welding scheme.