| DC03steel is a type of low carbon Al-killed steel, which is deoxidized completely due to the use of excessive deoxidizer. DC03steel sheet, the typical second generation of deep drawing steel, has quite low yield strength and tensile strength and good plasticity and stamping property. DC03steel sheets are being widely used in the products requiring high ductility such as automotive and electrical appliance parts.The production process of DC03steel includes smelting, hot rolling, pickling, cold rolling, annealing and smoothing. The microstructure of DC03steel at room temperature mainly consists of ferrite and free cementite. Experts and researchers are in agreement with that the cold rolling and annealing process have a great influence in the grain size of ferrite and the grade of free cementite. At present, the researches and achievements are concentrated in the continuous cold rolling process, while the studies on reversible cold rolling are rarely reported.In order to investigate the effect of the parameters of the cold rolling process and annealing process on DC03steel sheets, the samples in this paper were cold rolled in HC Single-stand reversing cold mill to different reduction ratio, then reheated to different temperature to recrystallize, and last tested the microstructure and properties of each sample.The study indicates that the cold rolling samples start to recrystallize around480centigrade and finish the recrystallization when the temperature rise to680centigrade. The size of grain is about the grade of8and the performance conforms to the requirements of DC03steel. The cold rolling ratio is an important parameter. The samples of70percent reduction ratio show the better performance in the plasticity and stamping property than ones of other reduction ratios. In addition, the experiment shows that the grain shape is flat when the samples are held for2hours at550centigrade before raised to700centigrade, which is beneficial to improve deep drawing properties of steel sheets. |
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