摘要
近年来,国内外高端汽车板用户对汽车板用冷轧板、镀锌板等产品提出“零缺陷”的要求,钢液中出现大尺寸钙铝酸盐夹杂物是造成IF冷轧钢板出现点状缺陷的主要原因,在钢板后续冲压过程中这些大尺寸夹杂物会造成冲压开裂。为解决IF钢冷轧汽车板中出现大尺寸钙铝酸盐夹杂物的问题,对国内某钢厂IF钢冷轧板中钙铝酸盐夹杂物的来源及控制开展了工艺研究。首先,通过扫描电镜和能谱仪分析了大尺寸钙铝酸盐夹杂物的形貌和成分,确定了钢包下渣是钙铝酸盐夹杂物的主要来源。开展了RH精炼顶渣改质、钢包下渣量优化、中间包内高挡墙和高液位操作的控制工艺研究,通过增加炉渣中w((CaO))/w((Al_(2)O_(3)))来降低渣中FeO活度,提高炉渣的表面张力,从而抑制了Al_(2)O_(3)夹杂物颗粒的聚集。在中间包内部采取高挡墙操作,中间包钢液取样分析发现挡墙前、后侧尺寸大于5μm夹杂物的数密度分别为7.83个/mm^(2)和5.57个/mm^(2)。采用中间包内钢液高液位操作时,发现液位高度提高140 mm可以使平均停留时间增加30.3 s。基于以上关键控制工艺,实现了IF钢冷轧汽车板中大尺寸钙铝酸盐夹杂物的稳定控制,缺陷发生率明显降低。
In recent years,the high quality automotive panel users both domestically and internationally have demanded"zero defects"for the cold-rolled steel sheet,galvanized steel sheet,and other products for automotive panels.The appearance of large-size calcium aluminate inclusions in the steel is the main cause of the defects in IF cold-rolled steel plates.In the subsequent stamping process of steel plates,these large-size inclusions may result in cracking during stamping.In order to solve the problem of large size calcium aluminate inclusions in cold rolled IF steel sheet for automobile,the source and control of calcium aluminate inclusions in cold rolled IF steel sheet in a domestic steel plant were studied.Firstly,the morphology and composition of large size calcium aluminate inclusions were analyzed by SEM and EDS,and it was determined that the ladle slag was the main source of calcium aluminate inclusions.The control process research of RH refining top slag modification,ladle slag quantity optimization,high weir in tundish and high level molten steel operation has been carried out.By increasing the w((CaO))/w((Al_(2)O_(3)))of slag to reduce the FeO activity in slag,the surface tension of slag can be improved,and the aggregation of Al_(2)O_(3)inclusion particles can be inhibited.High weir structure was established in the tundish,and molten steel sampling analysis found that the number density of larger than 5μm inclusions is 7.83/mm^(2)and 5.57/mm^(2)front and back of the weir,respectively.When the high liquid level operation of molten steel in tundish is applied,it was found that the average residence time increased by 30.3 s when the liquid level was increased by 140 mm.Based on the above key control measures,the stable control of large size calcium aluminate inclusions in IF steel cold-rolled automobile sheet was achieved,and the defect occurrence rate was reduced.
作者
曾立
罗衍昭
刘延强
赵长亮
季晨曦
徐海卫
ZENG Li;LUO Yanzhao;LIU Yanqiang;ZHAO Changliang;JI Chenxi;XU Haiwei(Manufacture Department,Shougang Jingtang United Iron and Steel Co.,Ltd.,Tangshan 063200,Hebei,China;Research Institute of Technology,Shougang Group Co.,Ltd.,Beijing 100043,China)
出处
《钢铁》
CAS
CSCD
北大核心
2023年第10期67-74,共8页
Iron and Steel
关键词
汽车板
钙铝酸盐夹杂物
RH顶渣改质
中间包高挡墙
渣改质
automobile sheet
calcium aluminate inclusions
RH refining top slag modification
tundish high weir
slag modification
