Study On Heat Utilization Of Slab During Hot Delivery And Hot Charging Process

Hot delivery and hot charging process of continuous casting slab is a kind of energy conservation and consumption reduction technology,which is of great significance to the transformation of traditional steel industry.Hot delivery and hot charging process can effectively improve product quality and production efficiency,but also the most direct and effective way for enterprises to achieve the aim of energy saving,emission reducing,cost reducing and efficiency increasing.In order to solve the problems such as lower hot charging ratio,serious wastage of billet afterheat,hot charging crack,this paper used field test and numerical simulation to analyze the billet temperature field and heat of the continuous casting process,stacking,quenching and reheating process,the main conclusions are as follows.(1)Field temperature measurement test shows that the center of broad face temperature of the slab is about 820～850℃,the narrow face slab center temperature is about 750℃and the corner temperature is about 700～730℃.To the quenching furnace,the broad center temperature is about 780～800℃,the narrow center temperature is about 685～695℃,the corner temperature is about 680℃;To stacking region,the narrow face center temperature is about 665℃;(2)The initial heat of molten steel is 1287kJ/kg,the slab lost 17.7%of the heat in the mould,3 8%of the heat in the secondary cooling zone,and about 5%of the heat in the roller conveyor.The available heat of the slab out of the casting machine is only 45%of the liquid heat;(3)The stacking time of the 3,5,8,and 10 slabs is 8.9h,12.8h,16.2h and 17.5h respectively.The heat ratio of the stacking process and the stacking initial state are 52.3%51.4%,51.1%,51.1%.The stacking process takes a long time and the heat loss is serious;(4)In order to prevent some hot charging cracks,the billet is quenched to make wideface distant 10 millimeter temperature lower than 600℃.The numerical simulation results show that quenching 90 seconds under the water flow of 4200 L/min can achieve quenching purposes.(5)The slabs heated to 1200℃ by different hot charging ways consume different time.Cold billet costs 4.8 hours,warm billet costs 4.1 hours,direct hot charging billet costs 3.2 hours,quenched billet costs 3.4 hours.The proportion of the heat absorbed in the furnace for warm billet,direct hot charging billet and quneched billet to cold billet is 64.4%,45.8%and 36.4%,respectively.