CAUSE ANALYSIS AND CONTROL OF HOT ROLLED WARPING DEFECT OF HIGH STRENGTH AUTOMOBILE STEEL
In the rolling process of high strength automobile steel,the surface defects of the strip frequently lead to product degradation and large economic losses.By means of acid attack test,metallographic microscope and microstructure analysis of the scanning electron microscope,it is confirmed that the main cause of the defect is the subtle microcracks in the corner of the billet.In order to further dig into the root of the problem,the whole process of continuous casting process control was deeply analyzed,the setting of mould vibration parameters and SEN insertion depth is not reasonable,and the equipment problems are also exposed,such as the inaccuracy of the equipment,which aggravates the formation of corner cracks.Based on the above analysis,by narrowing the crack-sensitive element control level,the mold negative slip time is reduced from 0.15 s to 0.13～0.14 s,and the mold powder with strong crystallization ability is adopted A series of control measures such as reducing SEN insertion depth and tundish overheat,tracing and confirming arc and roll gap accuracy of sector section before producing high strength steel,ensuring 100％accuracy of equipment,etc.,the defect rate of high strength automobile steel skin was reduced from 2.02％to 0.36％.
high strength automotive steelwarpingangle crackmoldpowdersuperheat
万方数据
维普
