| In this thesis the DDQ cold sheets rolled with CSP strips, produced on CSP continuous mill, Lianyuan Iron and Steel (Group) Company was studied. The main aim of the research work is to satisfy the demand of the customers on deep-drawing properties of cold rolled sheet. The effect of main processing parameters, such as deformation rate and annealing technology in cold rolling deep-drawing properties of the strip were studied. The main works of this thesis are as follows:(1)Annealing experiments of different technologies were conducted for the DDQ cold sheets rolled with CSP strips, produced on CSP continuous mill, Lianyuan Iron and Steel (Group) Company. The aim of annealing tests is to study the effects of different technologies on microstructure and drawing property of DDQ cold sheets. The optimum annealing technology was obtained on the basis of annealing experiments and was used in the annealing of DDQ sheets in cold plant, Lianyuan Iron and Steel (Group) Company. The annealing technology has been optimized for the production of DDQ cold sheets. Thus, the drawing property of DDQ cold sheets has been improved.(2)The mechanical properties of DDQ drawable cold sheets rolled with traditional technological production line in one iron and steel company and compact production line in Lianyuan Iron and Steel (Group) Company have been compared and analyzed. The effects of chemical compositions, metallurgical structure and inclusion on mechanical properties, especially on deep-drawing property, were analyzed. The results show that the deep-drawing properties of DDQ drawable cold sheets rolled with compact production lines are not so good as those of cold sheets rolled with traditional technological production lines, which is resulted from different chemical compositions and inclusions.(3) As the research, the quality of DDQ drawable cold sheets rolled with compact production line in Lianyuan Iron and Steel (Group) Company could meet customers'requirements. |
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