저널

The purpose of this study is to investigate behavior of surface oxide on the cold rolled sheet used for the drum material and its phosphatability. Phosphatability is dependent of the characteristics of surface oxide on the cold-rolled sheet and can be estimated by using the electrochemical method and measuring $ au$ value which is the time to be exposed to substrate Fe. $ au$ value is varied with the steel composition, width direction of the sheet and SPM length. The good phosphatability and uniform surface color can be obtained by increasing SPM elongation and decreasing FCS temperature.