Abstract: Hot steel rolling is amongst the most important industrial techniques because of huge amount of consumed resources, immense environmental impact, and the significance and enormous quantity of long products. Criteria for improving rolling operations include process efficiency, resource consumption, system reliability, product quality and ergo-ecological sustainability. There is an increasing availability of information within and beyond the domain of forming by rolling. With advances in computerised information processing, it becomes apparent that further progress is to be sought in intelligently combining the strategies and theories developed in differing disciplines. The key to optimising rolling systems is to be found in hybrid models. This approach calls for utilising cross-disciplinary knowledge, including a selection amongst methods such as stochastic, fuzzy and genetic modelling, process control and optimisation as well as supply chain and maintenance management. Evidence obtained by experiments using small-scale chemo-physical modelling encourages the use laboratory rolling for preliminary validations. Research strategy is conceptualised on the basis of a knowledge-based hybrid model. The sample space for this model is constituted by the rolling passes translated into the form of vectors. An example of a rolling pass translation into the vector form is presented.
Abstract: Strip shape is an important factor affecting the strip quality significantly during cold rolling of thin strip. In the paper, finite element simulation models of the strip shape in cold rolling for both symmetrical and asymmetrical rolling cases were successfully developed. The strip edge drop and the effect of the rolling force on the strip shape (the thickness distribution along the strip width) have been obtained. The developed finite element model has been verified with the experimental value, which shows they are in good agreement. The obtained results are applicable to control the rolled thin strip shape during cold rolling practice.
Abstract: In order to take into account the dynamic effects of molten metal during solidification, a methodology is presented to interface a metal solidification solver (coupled thermal mechanical metallurgical finite elements solver) with a specifically developed flow dynamics solver. (flow dynamics and thermics finite volume solver) The numerical set of tools is designed to be used for the simulation of bimetallic hot rolling mill rolls vertical spincasting. Modeling the industrial process for these products imply certain specifications on the numerical methods used, mainly due to the size of the geometrical domain, low Rossby & Ekman numbers, and a high Reynolds number.
Abstract: In order to analyze the effect of entry strip thickness, entry strip crown and intermediate roll shifting on strip profile and rolling force distribution, a three dimension finite element model of rolls-strip in UCM mill was established and employed. The results showed that the increases of entry strip thickness and entry strip crown would lead to the increase of exit strip crown and edge drop under the same total rolling force; the strip crown and edge drop would be decreased if the intermediate roll shifting δi was decreased. Moreover, the rolling force distribution also was analyzed in details by changing the entry strip thickness, the entry strip crown and the intermediate roll shifting.
Abstract: Axial force in CWR is an important force and energy parameter for stable rolling, which plays an important role in studying the forming quality of asymmetric shaft-parts, section shrinkage of rolled parts and rolling of heavy area reduction. By simplifying boundary conditions of solving axial projected area in this paper, and considering the effects of frictional force generated by contact surfaces between the tools and shaped shaft-section, the formula of the axial force has been derived by analytical method; by comparison of axial force values simulated by ANSYS/LS-DYNA FE software and measured through experiment, the formula of the axial force is verified correctly. The analyzing results provide useful reference for solving process problems caused by axial force.
Abstract: A set of new mathematical models have been developed to calculate the temper rolling force of 2050 strip temper rolling mill. Based on the fact of small plastic deformation and elastic deformation occurring on the entry and exit of the deformation zone, new stress boundary conditions are described. The inhomogeneous distribution of internal stress in thickness direction is taken into account in the models, instead of uniform internal stress and assumption of plane strain traditionally. The new mathematical models have been applied into the temper rolling of 2050 hot rolling mills with good results. Comparison of calculated values and testing values for nine typical products has been given. The result shows that the calculated value of rolling force of temper mill is accurate.
Abstract: High strength Al-Mg alloy strips with high Mg contents (5-10wt%Mg) were successfully fabricated by twin roll casting. In order to get a good surface quality of Al-Mg strips, an optimum process condition was investigated in this experiment. The morphology of the cast nozzle and the roll separate force during twin roll casting was important to improve the surface quality of the strip and homogeneity of the cast structure through the thickness. The size of intermetallic particle like Al-Fe compounds was reduced down to 1~2m due to a high cooling rate of Al melt during strip casting. In addition, the dendrite structure was very fine and the segregation of Al8Mg5 phase between grains was remarkably reduced. Therefore, the Al-Mg strips have good workability during additional cold/warm rolling processes. After annealing, the rolled sheets have superior tensile properties to a commercial high strength Al-Mg alloy sheet.
Abstract: This study performs DEFORMTM 3D three-dimensional finite element simulations to analyze the plastic deformation of A1100 / A3003 sandwich sheets during rolling. The finite element code is based on a rigid-plastic model, and the simulations in this study assume that the rollers are rigid bodies and that the deformation-induced change in temperature during rolling is negligible. The rolled product comprises a central sheet of A1100 aluminum alloy sandwiched between upper and lower sheets of either A3003 or A6063 aluminum alloy. The simulations examine the effects of sheet thickness and reduction ratio on the maximum effective stress, maximum effective strain, Y-direction load, and maximum damage induced within the rolled product. This study also compares the simulation results for the final thicknesses of the three layers in the rolled A1100 / A3003 (A6063) sandwich sheet with experimental measurements and bonding conditions.