| As an important aluminium fabrication product, hot rolled aluminum strip has been used widely in many fields including construction, packaging and transportation et al. In recent years, hot-rolled strip production has developed rapidly. The temperature variation of aluminum strip during hot rolling is one of the most important factors that will affect the size accuracy, mechanics capability of the product, the load distribution of rolling mill and energy consumption directly, which has always been the focus of strip production and research. However, there are many factors that influence the strip temperature in the process of hot rolling, and also, deformation and high temperature co-exist and interact with each other, so most manufacturers regulate rolling temperature only relying upon expensive and time-consuming trial and error approach from experience. But the effect is still not ideal. With the development of computer technology, numerical simulation is applied in strip rolling fields more and more widely. Therefore, the study of basic analysis theory and key technology of thermo-mechanical coupling analysis during multi-pass rolling process, establishing an finite element model which can represent accurately the strip rolling process, designing and analyzing the products and manufacturing process with the aid of advanced development tools have become particularly important.In this paper, through the research on the rules of the rheological behavior during 1235 aluminum alloy hot-rolled process, the corresponding artificial neural network prediction model of flow stress was established and applied to the finite element program successfully; a good foundation was laid to engineer calculations and numerical simulation of aluminum hot rolling process; accurate description of the strip multi-pass hot-rolling process and parameterized finite element analysis system was developed; the variation of the cross-sectional temperature field in the whole multi-pass hot-rolling process was analyzed by numerical simulation method; mathematical model of strip temperature drop, used for automated production control, was acquired. A research method was provided for the development of multi-pass hot-rolling technology. The main contents include:(ⅰ) A thermal simulation experiment was operated to examine the rheological behavior of 1235 aluminum alloy during hot deformation and study on the rules of rheological behavior on Gleeble-1500 thermal simulation tester. A theoretical basis was provided for designing, calculating and analyzing high-temperature-plastic forming process of 1235 aluminum alloy.(ⅱ) In view of deformation temperature, strain rate and strain on flow stress, the back propagation (BP) artificial neural network (ANN) was used to predict the flow stress of 1235 aluminum alloy. The input mode is X= (ε, Inε,1/T) and the output mode is Y= ln[sinh(ασ)]. A revised input parameter method and unification algorithm were proposed in this paper which enable the ANN to predict the flow stress accurately in wide range. It is found that the ANN with 3-15-15-1 is the best architecture for predicting the flow stress of aluminum alloy and the maximum mean square of its predicted value is 0.94MPa, with the research results showing that the accuracy of neural network prediction is much higher than that of the mathematical regression method.(ⅲ) To start with the basic equation of heat conduction of plastic processing, the force balance equation was introduced into energy conservation equation. The finite element formulation of elastic-plastic large deformation thermo-mechanical coupled analysis was deduced by building the solving of temperature and stress fields upon the current configuration, and a detailed solution procedure was included.(ⅳ) Contact friction simulation is the key factor to decide whether finite element analysis results are correct or not and also is a difficult problem of the finite element analysis. In the rolling direction, rolling deformation zone was divided into entrance sliding zone, sliding adhesive zone and export sliding zone. The contact friction force calculation model of three-section mixed friction mechanism was proposed using a segment which is similar to the sub-shear friction theory. The shear friction incontinuity in the neutral point was solved effectively, and the vertical and horizontal friction was made to be zero when entering and leaving the deformation zone.(ⅴ)How to use artificial neural network to predict the material flow stress easily and efficiently is another problem in FEM analysis. On the MSC.MARC platform, the research materials-1235 aluminum alloy user library was defined. The perfect combination of artificial neural network prediction model and large-scale finite element software of flow stress was achieved by this method. (ⅵ)By setting the Multiple load cases correlated with the running pass, and then by creating multiple rollers and impellent rigid-bodies, and setting the contact relation with the rolling, the trip can bite smoothly and the multi-pass continuous rolling process was simulated in the finite element software MSC.Marc. A set of automatic Modeling System of finite element analysis for hot-rolled process is developed. We established an strip rolling 11 consecutive numerical simulation model aluminum alloy 1235 strip to get temperature falling curves at center, medium and surface of the same sect of 1235 aluminum strip during the process from outlet of heating furnace to end of 11th pass rolling. The results showed that the calculate result is consistent with measured result.(ⅶ) Studying the law of temperature fall of strip that is influenced by the rolling speed, emulsion heat transfers coefficient, tapping temperature and environmental temperature by orthogonal test. Establishing a mathematical expression/about/under temperature falling with the change of process parameters by regression analysis, a theoretical basis for process parameters design, analysis and energy optimization was provided.(ⅷ) Hot temperature testing laboratories of aluminum strip were carried out on the experimental rolling mill. Discussing the law of the effects to strip temperature of different process conditions and comparing the experimental results with numerical results, the establishment of the coupled thermo-mechanical model was verified.
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