: Skin pass mill with capacity of producing 600000 ton strip per year, is one of the most important mills in Mobarakeh Steel Complex. A small fault in this equipment causes many defects in strip and reduces the strip quality. The aim of this thesis is investigation, finding, analyzing and suppression of appearing of chatter marks on strip surface. In chapter one we define chatter in rolling process, then, in second chapter the pervious formulation of rolling process is discussed and the formulation that is used in this thesis introduced. In third chapter the structure model of skin pass mill that is created based on mill parameters is introduced, after that, in forth chapter the model created in Simulink software is discussed and in fifth chapter the results of many simulations illustrated through diverse charts and figures, for example, mill behavior is investigated, using established linear system analysis methods, as a function of a number of mill operational parameters, such as friction coefficient, strip entry velocity, strip width and thickness and forward and backward tensions. The effect of each parameter on mill stability and chatter onset has also been studied. Finally, in chapter six the industrial observations in previous year in Mobarakeh Steel Complex and the results got from them are discussed and the possible ways of suppression of chatter in skin pass mill are introduced.
