CONTROL OF COIL SHAPE QUALITY OF HOT ROLLED HIGH STRENGTH STEEL STRIP
The plate shape defects of hot coils produced by HBIS Group Tangsteel Company are mainly caused by double-sided wave and plate shape warping,which seriously affect the stability of quality control of downstream users such as leveling quality and laser blanking and the improvement of production efficiency.In this paper,the causes of DS side wave in hot rolled high strength steel sheet are analyzed from the aspects of rib(100 mm away from the edge of the strip)and edge temperature difference control,hot rolling process parameter setting,layer cooling process selection,and side spray opening on both sides of the strip,and the measures to reduce the internal stress of hot rolled strip are given.It is found that the edge temperature of the strip is about 50～90℃lower than the rib temperature of the strip.The strip in this area is in the maximum heat transfer area,and the heat transferred from the strip is the most.Therefore,the temperature in this area shows a sharp downward trend and the temperature changes are large,which is the main cause of the edge wave generated by the final plate shape of the strip.The temperature difference between the rib and the edge of the hot rolled strip is related to the width reduction of the fixed width machine and the final rolling temperature.The constant width of 200～250 mm can reduce the temperature drop of the edge of the strip by about 20℃than that of the constant width of 50～100 mm,and the final rolling temperature can decrease from 895℃to 885℃.In order to better control the shape quality of hot rolled strip,the selection of layer cooling process should be based on the cross section temperature difference of strip steel at the exit of finishing rolling,combined with the microstructure and grain uniformity of each steel grade and specification in the cooling process.
tropical slabcross section temperature differenceinternal stresslayer cooling processfixed widthfinal rolling temperature
万方数据
维普
