Resistance spot welding (RSW) includes many variables that can influence the weld properties. The purpose of this study is to develop an analytical model for prediction of thermal history and weld microstructure in RSW and to find the most important process parameters that influence the weld microstructure. A one dimensional model is proposed for prediction of thermal history during cooling step of RSW process. The reliability of analytical model is evaluated by experiments and numerical simulations. The calculations reveal that the current analytical model is reliable particularly at temperatures lower than Tm/2. Sheet surface temperature at electrode-sheet interface and sheet thickness are recognized as the most important factors influencing cooling rate at T
