شبيه سازي ديناميكي اثر لوپر بر ضخامت ورق در فرآيند نورد گرم

چكيده انگليسي :

Dynamic Simulation of Looper Effect on Thickness in the Hot Rolling Process Mohammad Mahdi Mohammadi Najafabadi mm mohammadi@me iut ac ir Date of Submission 2015 08 22 Department of Mechanical Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language FarsiSupervisor Dr Mohammad Reza Forouzan forouzan@cc iut ac irAbstractHot rolling is an essential industrial process in the production of sheet steel In the hot strip mill process in theiron and steel industry reheated slabs are rolled to the required strip thickness and width at the roughing andfinishing mill In the finishing mill the strip thickness reduces while the strip passes through each of the 7stands by controlling the gauge Between each two stands there is a looper which is a motor driven arm Thefunction of the looper is to keep the strip at a reference tension Looper and tension control are important inhot strip mills because they affect the strip quality In addition it is important to properly recognize interactionsbetween sub divisions and the rolling stands Looper is one of the important parts in the finishing mill processthat should be investigated more Moreover studies about important parameters sources of disturbance effectson the product and related control systems with looper have been carried out Then dynamic equations forrolling stands and looper system is provided These equations have been obtained comprehensively andaccurately that have provided the proper grounds for simulations An innovative sliding mode controller forlooper and tension control in hot strip finishing mills was developed based on approximately linearized model A finishing mill performs a set of operations in a hot strip rolling mill and a complex unit including manyprocesses and control loops A dynamic model of hot strip rolling with looper system has been developed Themodel has two main sub models the stand elastic model and the strip rolling plastic model Roll surfaceflattening and the material strain rate hardening are the main sources of the nonlinearities in the mill and therolling process sub models respectively All simulations were performed by MATLAB software The Simulinktool of the MATLAB software was employed to simulating the interactions of the sub models Results arecompared with the available experimental records by Mobarake Steel Complex MSC Empirical andsimulation figures are verified together and performance of program is approved Besides new results havebeen obtained by simulation Specifically the effect of thickness on the rolling force and looper response ispresented Looper response for different rolling speeds and strip thicknesses has been studied Furthermore theeffect of strip tension variations on thickness created by looper has been presented The results have also shownthat the roll load decreases with increasing interstand tension Based on this simulation technique valuableinformation can be easily obtained for possible improvements on rolling processes in the future As well asanalytical solutions might be compared with numerical solutions obtained from finite element simulation which is left as a future work Keywords Hot strip finishing mill Looper dynamic Looper control Interstand tension Simulation

محمدي نجف آبادي، محمدمهدي

شبيه سازي ديناميكي اثر لوپر بر ضخامت ورق در فرآيند نورد گرم

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