Thermal Coupling Numerical Simulation Of Hot Rolling For Wide Aluminum Alloy Plate And The Heat Transfer Experimental Study On Emulsion

Wide aluminum hot rolling is the main method of production of wide aluminum strip,high quality strip products can produced by using this method. In the process of aluminum strip, The aluminum plate parameters such as temperature, stress control is very important in the hot rolling process,especially for wide aluminum plate,because the width dimension is large, the temperature and stress distribution along the width direction easily uneven, and the non-uniformity of temperature, stress and strain are directly affect the strip surface quality and mechanical properties after rolling. Rolling emulsion cooling process is one of the important factors affecting rolling temperature field, In the current research on numerical simulation of aluminum strip processing, the heat transfer boundary of emulsion is too simple, do not tally with the actual heat transfer process in the aluminum plate hot rolling process, lead to inaccurate mathematical model and reduces the accuracy of the simulation results.Aiming at the problems in the aluminum plate rolling, this paper developed a new wide aluminum plate strip thermal coupling mathematical model. In this model a workpiece surface with the rolled piece and roll interface moving boundary was set up to show the emulsion cooling heat transfer boundary condition, the emulsion cooling heat transfer coefficient was calculated by using experimental method. By means of numerical simulation of the width of 2700 mm (blank width) aluminum alloy plate in "1 +4" hot rolling process and the influence of emulsion injection quantity on temperature and stress-strain field is studied.The main research contents and results are as follows:①With width 2700 mm extra-large aluminum plate in "1+4" continuous hot rolling process as the research object, a new wide aluminum plate thermal coupling mathematical model was developed. In this model a workpiece surface with the rolled piece and roll interface moving boundary was set up to show the emulsion cooling heat transfer boundary condition, it’s realizes the accurate description of the emulsion heat transfer boundary conditions for rolled plate, the heat transfer boundary of emulsion processing is more accord with the actual rolling process, the accuracy of the model was improve by this method.②In the developed new model, the heat transfer coefficient of emulsion in heat transfer boundary between emulsion and rolled plate was obtained by experimental method. Therefore, the heat transfer coefficient of emulsion test experiment platform was designed according to the principle of one dimensional unsteady heat transfer, and the heat transfer principle of heating system was calculated by using the heat balance, the emulsion and the aluminum plate heat transfer coefficient test experiment platform was made according to the design scheme.③The heat transfer characteristics of emulsion was researched based on self-designed experiment platform. The heat transfer coefficient under different spraying quantity emulsion for aluminum plate cooling were obtained based on inverse heat transfer algorithm, provides the emulsion cooling heat transfer coefficient for heat transfer boundary.④the temperature, stress and strain of the wide aluminum plate during the whole hot rolling process is studied, the results showed that:In the width direction, the surface of the nodes and the central node of the temperature field was then decreased trend, from 13th to 15th passes, the lateral surface temperature difference between margin and center of rolled piece is biggest reach 44 ℃.The stress distribution on the width direction is not uniform, the stress of the width is greater than the other nodes on the edge in the first rolling pass, the stress difference of node between center and edge around 13 Mpa, the stress difference is around 6 Mpa in ninth rolling pass; Stress get into the center along the thickness of the rolled piece with the rolling pass, and its inhomogeneity distribution in the length direction is larger, the volatility is smaller width direction.⑤Using developed wide aluminum plate strip three-dimensional thermal coupling mathematical model, the effect of emulsion injection quantity to temperature, stress and strain of the wide aluminum plate during the whole hot rolling process is studied. The results show that:the temperature drop in surface and the transverse temperature decrease is bigger in each passes with the increase of injection quantity, when emulsion injection quantity is 1350 L/(min·m2), the largest temperature drop value in ten rolling pass is about 110 ℃; Rolling stress increases along with the increase of the emulsion injection quantity, when emulsion injection quantity increased from 950 L/(min·m2)tc 1350 L/(min·m2), the stress of the plate increased from 72.9 Mpa to 75.5 Mpa; the strain increase speed of the surface nodes along the width edge became bigger with the increase of injection quantity, while the strain of plate decreases, and the deformation degree is reduced.