Study On Stamping Forming Performance Of Light Alloy With Welding Heat Source

Light alloys mainly includes aluminum alloy,magnesium alloy and titanium alloy.Where aluminum alloy has the advantages of good corrosion resistance,high specific strength,easy processing and excellent price,etc.Magnesium alloy is the lightest commercial metal structure material in the world,which is widely used in many fields Magnesium alloy is the world’s lightest commercial metal structure materials,widely used in many fields.Due to the aggravation of environmental pollution and greenhouse effect,the use of aluminum alloy and magnesium alloy to realize the lightweight of automobiles,airplanes and ships is one of the effective methods to solve environmental problems.However,at room temperature,both aluminum alloy and magnesium alloy are prone to fracture,which seriously affects their wide application.Welding technology is under the condition of high temperature or high pressure,using welding materials to connect two or more pieces to be welded into a whole operation method,is a local rapid heating and cooling process.In the whole process of welding,the local structure and structure of the welded material have changed,which can be used to improve the formability of the sheet metal.In this paper,the surface pretreatment of 6061-t6 aluminum alloy and AZ31 magnesium alloy was carried out by tungsten argon arc welding(TIG)as an auxiliary heat source.Then,according to the technical characteristics and practical needs,friction stir welding(FSW)was used as the input heat source for 6061-t6 aluminum alloy,and the performance results were tested through the cup process experiment.The results are studied,analyzed and predicted by means of macro and micro organization observation,hardness test,local mechanical property test and machine learning method.Firstly,arc pretreatment of 6061-t6 aluminum alloy and AZ31 magnesium alloy was carried out to observe the structure and test the forming performance,hardness distribution and mechanical properties of each structure.It can be obtained that the arc current of 100-130 a can soften the aluminum alloy,the bending Angle can reach 60°,the performance improvement ratio is up to 105%,and the springback amount reduces by 0.19 mm,and the improvement ratio is 68%.The arc energy causes the hardness of the plate to decrease within the range of 3mm in the processing center,and the grains in the formed heat-affected zone are transformed into approximately equiaxed crystals by heat,thus obtaining greater strain hardening potential,and the hardness can be restored in the forming process.After arc treatment,the microstructure of AZ31 magnesium alloy can be changed within the range of 4mm on the surface and 10 mm on the back.With the increase of the current,the forming performance of sheet metal showed a trend of first strengthening and then weakening,and reached the best at 60 A,the bending Angle reached 98°,which was 88% higher than that of the base metal.After the 60 A current treatment,the longitudinal structure of the plate was successively distributed according to the melting zone,semi-melting zone and heat affected zone.The recrystallization and grain growth occurred in the heat affected zone effectively improved the plasticity of the zone.The structure of the heat-affected area has the characteristics of high elongation and low hardness.The hardness of the melting area is similar to that of the heat-affected area,with the elongation rate being 81% of that of the heat-affected area.The hardness of the semi-melted area is higher,but the elongation rate is only 73% of the heataffected areaIn this paper,the rotation speed,walking speed and pressure of the tool are used as input variables,and the cup value and the maximum stress value of the plate are the output variables and a MSL-SVR model has been established.There is a very high correlation between predicted output variables and tests(correlation coefficient: Rc= 0.9538,Rs= 0.9019)and the RMSE of the output values are 0.1180 mm and 95.2271 N.The algorithm also ensures the balance between the output variables,and model’s robustness.