Influence Of Rolling And Annealing Process On Mic Rostructure And Prope Rties Of 5182 Aluminum Alloy For Automobile Sheets

Lightening automobile's body weight is the best way to reduce energy consumption and environmental pollution as well as promote the sustainable development of the automobile industry.Aluminum alloy as the significantultralight material has attracted more and more attention.It is possible that 5xxx series aluminum alloy sheets were used to replace plate steel materialsof the car for its suitable strength and good formability.It has great significancethat studying the effects of connection between processing craftandmicrostructure and propertiesto produce high performance aluminum alloy sheets.In this study,5182 aluminum alloy with high magnesium content in 5xxx series aluminum alloy was selected as the research objec t.Through the study of single pass compression test,cold rolling and annealing process,the high temperature flow stress model,dynamic recrystallization model,processing map and the optimum hot deformation,cold rolling,annealing process parameters were obtained;by compared the microstructure and properties of Al-Mg alloy and 5182 aluminum alloy.Research results showed that:?1?We simulated single pass compression test on 5182 aluminum alloy and got the flow stress constitutive equation of 5182 aluminum alloy at high temperature,in which the deformation activation energy Q was 155.50kJ/mol,and the flow stress equation was:?2?The model of peak strain and critical strain of dynamic recrystallization of 5182 aluminum alloy was established.?_c= 0.72?_p,?_p= 5.4402 × 10^-5?^0.1822 exp 38840 RT?3?During the hot deformation process,the strain rate has great influence on the microstructure.At low strain rate,the alloy formed a large dynamic recrystallization grain size,the grain size of dynamic recrystallization was more and more smallwith the increasing of the strain rate;With the deformation temperature increasing,the recrystallization degree of the alloy was more sufficient and the grain size increaseed;The dynamic recrystallization grains grew up obviously with strain capacity increasing.?4?Made a processing map of the 5182 aluminum alloy in the true strain of 0.2 and 0.4,5182 aluminum alloy has a high power dissipation factor region when the true strain was 0.4 and the power dissipation efficiency factor was greater than 41%,in which the strain rate was 0.01¹s^-1,the processing temperature was between 400 and 500?.By comparing the microstructure and processing map under the differ ent conditions of the thermal deformation,the best hot working conditions were 450?and the strain rate was 0.01⁰.1s^-1.?5?By comparing thedifferent cold rolling processes,it was concluded that the strength of the two cold rolling process was higher tha n that of the one cold rolling process.When two times of cold rolling,the larger the final cold rolling reduction,the smaller the grain size of the alloy,the higher the strength of the alloy.The grain size of the alloy increases with the annealing temperature increasing.At 450?,the grains of the abnormal growth.With the annealing temperature increasing,the mechanical properties of the alloy showed a downward trend,but in the annealing temperaturewas 350?,formability of the alloywas best.Under the same annealing temperature and annealing time form0.5 to 8 hour,with the increase of the annealing time,the microstructure of the alloy did not change,the grain size did not grow up,and the properties of the alloy remained basically unchanged.It is concluded that the optimum annealing process is:among the total cold rolling working rate is 33.3%,the finished cold rolled the total working rate is 75%,the annealing temperature is 350?,holding timeis 1² h.?6?Contrasting experiments were carried out under the best processing conditions,when ensured the forming performance guarantee not reduce,the strength of alloy could be improved by more than 30 MPa,raised the ultimate goal of strength of the alloy sheets.