Simulation Of Welding Deformation Of Forklift Hydraulic Cylinder Bearing And Optimization Of Welding Process

As an important assembly method,welding plays an important role in the manufacture of automobiles and construction machinery.Due to the uneven distribution of heat during the welding and cooling of the components,residual stress and deformation will inevitably occur.Residual stress causes stress concentration,which leads to the decrease of mechanical strength of the component,and it affects the service life and safety performance of the product.Excessive welding deformation affects the assembly precision of the product,and the post-weld correction is time-consuming and labor-intensive,which restricts the production efficiency.In this paper,the hydraulic cylinder bearing of forklif is taken as the research object.For the actual welding production of hydraulic cylinder bearing,the welding deformation is large and the coaxiality error of the two pin holes is large.Based on the thermo-elastic-plastic finite element theory,the welding process of the bearing is numerically simulated and combined with the experimental analysis to study the welding residual stress and deformation law.On this basis,the welding process of the hydraulic cylinder support is optimized to control the welding residual stress and deformation to improve product assembly quality and safety performance.Firstly,the technical requirements of the hydraulic cylinder support structure and the characteristics of the welding process are described.The problems existing in the welding production are analyzed.It is pointed out that the welding process parameters and the welding sequence are unreasonable,which leads to the large deformation of the bearing and the large error of the coaxiality.Secondly,according to the welding heat input characteristics of the hydraulic cylinder support,the double ellipsoid heat source model is used to simulate the typical T joint of the bearing,and the T-joint welding test is carried out under the same welding conditions.The macroscopic morphology of the joint pool is observed.The comparison test was carried out to complete the check of the heat source model.On this basis,the numerical simulation model of the hydraulic cylinder support is established,and the stress field and strain field are analyzed.The residual stress and deformation law of the support under the current production process are obtained.At the same time,the residual stress and welding deformation of the support are obtained.The test results are compared with the numerical simulation results to verify the accuracy of the numerical simulation model.Finally,in the control research of welding residual stress and deformation of hydraulic cylinder support,according to the actual production conditions of the workshop,the single factor test and orthogonal test are designed to analyze the influence of each welding parameter on the welding residual stress and deformation of the hydraulic cylinder support.The optimum welding process parameters are 1mm welding gap,welding current 220A,welding speed 8mm/s.The welding sequence of the hydraulic cylinder bearing is optimized from the welding sequence and welding direction,and the optimal welding sequence is obtained.The results show that:when the combination of symmetrical welding and cross-bumping is adopted and the welding direction is uniform,the welding residual stress and deformation are minimized;the welding production verification is carried out under the optimal welding process,which is better than the original welding process.The welding process has a significant reduction in welding residual stress and welding deformation,and the product assembly quality is significantly improved.The research results of this thesis provide a basis for guiding the development of the actual welding process of the forklift hydraulic cylinder support.