Study Of Formability Properties Of 5182 Aluminum Alloy Automobile Plate

As the light-weight metal structure material,5182 aluminum alloy has been used in limousine body covering parts,which have excellent properties such as high ratio of strength to weight,good corrosion resistance,excellent weldability and recycling capabilities. However,compared with the steel sheet, 5182 aluminum alloy has low formability at room temperature. In addition,5182 aluminum alloy will occur dynamic strain aging(DSA) in forming process, which lead to stretcher strain marks on the surface of products, and reduce the surface quality of the products. Therefore,in this paper, influence of blank holder type on the drawability of 5182-O aluminum sheet at room temperature and effect of strain rate on the formability of 5182-O aluminum alloy at room temperature and 200 °C were studied. The microstructure evolution during deformation has been characterized using metallographic analysis. These researches is to provide theoretical basis for 5182 aluminum alloy sheet surface control and provide theoretical basis for the formulation of aluminum alloy sheet stamping process. The main research contents and results are as follows:(1) Cold-rolled 5182 aluminum alloy sheet complete recrystallization after annealing at 330 °C for two hours. However, grain along RD is slightly elongated which was not the equiaxed grain. 5182 aluminum alloy sheet exist a typical rolling texture components Copper {112} <111>, S {123} <634> and Brass {011} <112>.(2) The LDR of 5182-O aluminum alloy sheet is 1.7 and the earring ratio is 16.6% by using flat blank holder. The degree of sheet metal flange deformation increasing with the increased of the DR. The flange would divorced from flat blank holder when sheet metal in the shoulder of the die. The drawn cup occurred wrinkles due to lack of blank holder force which result to transition metal flow. Comparing with using flat blank holder, the curved blank holder could provide effective blank holder force which controls the metal flow Inhibition flange instability wrinkling. Therefore, the LDR of 5182-O alloy sheet was enhanced to 2.0. In addition, the earring ratio was also reduced to 4.3%.(3) Due to dynamic strain aging appears when 5182 aluminum sheet uniaxial tension at room temperature, the serrated curve true stress-strain and stretcher-strain marks were observed at low strain rate. With the strain rate increased, amplitude and frequency of serrated wave were weakening, stretcher-strain marks was disappear and the tensile strength of 5182 aluminum alloy was decreased. At 200 °C, true stress strain curve becomes smooth owing to DNS disappeared. With strain rate increased, due to work hardening dominant, the tensile strength of 5182 aluminum alloy sheet is increased and fracture elongation is decreased.(4) 5182 aluminum alloy sheet has poor forming performance at room temperature. Therefore, the Erichsen value of aluminum alloy is low at room temperature and the minimum value is 7.8 mm. Because of the dynamic strain aging effect on aluminum alloy at lower strain rate, which enhanced the strength of aluminum alloy and decreased the formability of aluminum alloy. The Erichsen value increased with the increase of forming speed and it can reach 8.4 mm. However, compared to room temperature condition, the Erichsen value of aluminum alloy is increased to 10.5 mm, increased by 34.6%, deformation at 200 °C. It is owing to dynamic recovery improved the formability. Due to the dynamic strain aging effects disappear, under work hardening dominant, Erichsen value decreased with the increase of forming speed.