Study On Deformation Behavior And Grain Refinement Of Industrial Pure Aluminum Sheet In Process Of Stepping Continuous Extrusion-rolling

Thermo-mechanical treatment methods are a kind of important way to refine grains for improving the performance of metal materials and they have been widely used in industrial production, such as the traditional rolling, forging, extrusion and other plastic processing methods. With the development of technology, it could make the grain size of metal refine to sub-micron order by adopting serve plastic deformation methods, and these ultra-fine crystal material preparation technologies are paid widely attention by materials workers both at home and abroad for their lots of advantages of producing large dense material, simple process and low cost. Meanwhile the traditional plastic processing methods are also limited by passes deformation value and total deformation value. While the serve plastic deformation methods that are used for the preparation of ultra-fine crystal overcome these limitations, these methods are limited to be applied to industrial production because of the size of deformation metal. Therefore the article proposed a new method of large plastic deformation 梥tepping extrusion-rolling deformation method, we designed and manufactured the experimental device independently, and studied the deformation behavior and microstructure evolution of metal sheet in extrusion-rolling deformation process.This article selected 3mm-thick 1060 industrial pure aluminum sheet as the experimental materials to study the extrusion-rolling deformation behavior and the grain refinement. The following results were obtained through FEM analysis and extrusion-rolling deformation. In the given conditions of materials and deformation, when the stepping length is 20mm and the advancing speed is 5.0mm/s, the extrusion-rolling deformation process could proceed smoothly; In the certain advancing speed, when the rotation rate is less than 0.68 rpm (that is, the angular velocity is 1/14 rad/s), shear deformation rate is proportional to the rotate speed of roll and the coefficient of friction between roll and the sample, when the rotation rate is more than 0.68 rpm (that is, the angular velocity is 1/14 rad/s) shear deformation rate is only proportional to the coefficient of friction and has nothing with the rotation rate of roll. When the extrusion deformation is 4 passes, the annealing temperature is 200℃, the annealing time is 10 min, the article obtained the most fine,uniform and round grain. The average grain size of cross section and longitudinal section is each 9.04μm and 12.20μm. But when the extrusion-rolling deformation is above 4 passes, the article found the heat from the contact between sample and roll made adverse effects on the grain refinement. The studies of paper have shown stepping extrusion-rolling deformation method could make the metal materials produce plastic deformation continuously, and can make the grain refine.