The main purpose of the present thesis is to analysis the effects of variation of rolling speed in tandem cold rolling process. At the beginning, the various factors, which are in fluencive on tearing of strip, such as manual effects, equipments and strip defects,are studies. Using theoritical equation, the main parameters of tandem cold rolling are calculated and are copmared with practical results of tandem cold rolling line in Foulad Mobarake steel company and calculated parameters were validated. Then, the tandem cold rolling pocess was simulation by means of finite element software, ABAQUS\Explicit and damage critria was defined as strip’s tear criteria. Among various damage models available in ABAQUS software, FLD damage was selected. Erichsen test was applied on St12 steel sheett model to extract. Correlated parameters to following that, results of simulation of tandem cold rolling were compared with practical and analytical results and validated. Consequently, variations of rolling speed and it’s effects on strip’s tear were analysed. Key Words Tandem Cold Rolling, Velocity Variation, Tearing of Sheet Metal, Damage, Forming Limit Diagram (FLD), FLD Damage, ABAQUS, Finite Element Analysis.