Study On Incremental Sheet Forming Of Dissimilar Aluminum Aiioy Tailor Welded Blanks

Incremental sheet forming(ISF)process is a new flexible sheet metal forming technology.Compared with traditional forming technology,it has the advantages of independent of die,low cost and high forming performance.It is especially suitable for the development of new products and the production of single small batch products.Tailor welded blanks(TWBs)can obtain different performance in different parts of parts,and can meet the needs of different working conditions.The application of TWBs has attracted more and more attention.However,the forming technology of TWBs is not mature enough,there are still problems of low formability and forming quality.To solve these problems,this paper takes 5052/6061 dissimilar aluminum alloy TWBs as the research object,and studies the ISF of TWBs.Based on orthogonal experiment,the friction stir welding(FSW)process of5052/6061 dissimilar aluminum alloy was studied.Through the range analysis and variance analysis of the experimental results,the influence order of different process parameters on the mechanical properties of the joint is found,and a group of process parameter combinations that make the mechanical properties of the joint reach the best are found.The results show that within the range of selected process parameters,the rotation speed of stirring head has the greatest influence on the mechanical properties of the joint,followed by the welding speed,and the influence of the amount of reduction is the least.Based on numerical simulation,the ISF process of fixed angle conical cup from5052/6061 dissimilar aluminum alloy TWBs,5052 sheet and 6061 sheet was studied.The finite element software is used to simulate the ISF process of fixed angle conical cup of 5052/6061 dissimilar aluminum alloy TWBs,5052 blank and 6061 blank.Through the numerical simulation results,the variation laws of equivalent stress,plastic strain,sheet thickness and deformation force in the ISF process of TWBs are summarized,and compared with 5052 blank and 6061 blank.The results show that the maximum value of the equivalent stress of TWBs formed workpiece appears at the junction of the weld area and the base metal area,and its maximum value is between 5052 blank and 6061 blank formed workpiece,but the overall difference is not much.The weld area of the TWBs formed workpiece is close to the two-way tensile state during the ISF process,while the base material area on both sides is close to the plane strain state.The thickness distribution of the TWBs formed workpiece is uneven,and the minimum thickness value appears at the junction of the weld area and the base metal area.The change of axial deformation force of TWBs,5052 blank and6061 blank during ISF mainly goes through three processes: gradually increasing,stabilizing and gradually decreasing.When the axial deformation force increases to a certain value,the fluctuation range of axial deformation force of welding plate is greater than 5052 blank and 6061 blank.Based on experiments,the ISF formability of 5052/6061 dissimilar aluminum alloy TWBs was studied.Firstly,based on the orthogonal experiment,the ordinary single point incremental forming(SPIF)experiment of TWBs is carried out.Through the range analysis and variance analysis of the experimental results,the influence order of different process parameters on the ISF performance of TWBs is found,and the best combination of process parameters is found;Then,based on the optimal process parameters,the influence of special ISF on the formability of TWBs is studied.Through the study,we found that the fracture position of the TWBs mainly appears at the junction of the weld area and the base metal area,and a few cases will appear in the weld area.In the ordinary SPIF experiment,the diameter of the tool head has the greatest impact on the formability of the TWBs,followed by the lubrication method,the Z-axis feed amount and feed rate have the least impact.The friction stir ISF in the special ISF can significantly improve the formability of the TWBs.Based on the response surface method(RSM),the forming quality of ISF workpiece of 5052/6061 dissimilar aluminum alloy TWBs was studied.Taking the forming accuracy and surface roughness as the research objects,the variation of the forming accuracy and surface roughness of TWBs ISF workpiece under different process parameters was analyzed.The study found that the Z-axis feed and the quadratic of the tool head had a significant impact on the forming accuracy of the TWBs formed workpiece,compared with the 5052 blank and the 6061 blank formed workpiece,the forming accuracy of the TWBs formed workpiece was lower than that of the 5052 blank formed workpiece and higher than that of the 6061 blank formed workpiece.The tool head diameter,the Z-axis feed and the interaction between the tool head diameter and the Z-axis feed had a significant impact on the surface roughness of the TWBs formed workpiece,and the surface roughness of the welding seam area of the TWBs formed workpiece was not much different from the base material area on both sides.