Titanium Alloy Medium Thick Plate TIG Welding Test Research And Simulation Analysis

Titanium alloy has many excellent properties such as high specific strength and good corrosion resistance.Therefore,titanium alloy weldments are widely used in marine engineering,aerospace and other fields.Welding titanium alloys with general welding methods is very prone to problems such as welding defects and excessive welding deformation.Relatively better quality welding joints can be obtained using TIG welding.However,due to the low penetration of TIG welding,it is not possible to form a medium-thickness titanium alloy plate at one time.Therefore,this paper first uses the TIG welding method to perform multi-layer multi-channel welding experiments on 6mm thick titanium alloy plates.Through this experiment,the influence of different process parameters on the quality and mechanical properties of the weld is explored.The experiment aims to solve the weld quality problem generated by medium thickness titanium alloy plate during the welding process.The multi-layer multi-channel welding experiment of titanium alloy is too long,the material is expensive,and it is difficult to measure the physical quantities such as stress field and phase transition in the experimental process.In this paper,aiming at the problem of excessive welding deformation,numerical simulation method is used to optimize and analyze the multi-layer multi-channel welding experiment of titanium alloy.In this way,the influence of the welding process on the residual stress and deformation of the test plate is explored.This study provides a reference for the practical application of multi-layer multi-channel welding process of titanium alloy medium thickness plate.The specific research content is as follows:(1)Through multiple welding tests,welds with good surface morphology such as no cold cracks and no oxidation are obtained,and the optimal titanium alloy TIG welding process parameter range is determined.The influence of process parameters such as welding current,welding speed,and wire feeding speed on weld quality is analyzed experimentally.The optimal process parameter selection is based on the above experiments.In this paper,two different filled welding wires are used for welding experiments to detect the quality and mechanical properties of two welded joints.Through comparative analysis,the addition of pure titanium welding wire when welding TC4 titanium alloy can improve the plasticity of the joint and reduce the generation of cold cracks.The microstructure of two welded joints in three regions was investigated.(2)The establishment of simulation model is based on SYSWELD software.The multi-layer multi-channel TIG welding of 6mm thick titanium alloy plate is numerically simulated and its heat source is checked.A heat source model that fits well with the actual heat source is then obtained.The actual measured angular deformation results are compared with the simulation results to verify the accuracy of the simulation.The data obtained from the simulation are analyzed to explore the changes in physical quantities such as phase transitions,temperature fields,stress fields,and deformation quantities that are difficult to measure during actual welding.(3)Simulating the welding process under different process parameters is based on SYSWELD software.In this way,the influence of different heat inputs,groove angles and other parameters on residual stress and deformation of the test plate is explored.The method of adjusting the process parameters can have a certain effect on reducing the residual stress of the test plate and reducing deformation.Based on the simulation results,the effect of rigid constraint method on residual stress and deformation of weldment is investigated.The variation law of residual stress and deformation of the test plate under different pressure plate widths and different distances between the plate and the weld seam was obtained.This method can effectively reduce the deformation of the test plate,but cannot reduce the residual stress of the test plate.Based on the simulation results,this experiment explores the influence of temperature difference tensile method on residual stress and deformation of the test plate.The residual stress and deformation variation law of the thermometric tensile method at different temperatures and different temperature bands and weld distances are summarized.Compared with the rigid constraint method,this method can effectively reduce the residual stress of the weldment while reducing its deformation.