摘要
连铸坯网状裂纹隐藏在铸坯亚表层,人工在线检查时难以发现,加热炉烧损量不足时容易造成轧材大量的起层(起皮)缺陷。通过轧材和铸坯金相检测分析,明确了起层缺陷的原因来自铸坯网状裂纹;针对全弧形连铸机板坯网状裂纹问题,分析了低合金钢的典型元素(C、Al、N、V)、结晶器冷却强度、连铸保护渣、二冷强度等相关因素对铸坯网状裂纹缺陷的影响规律,明确了铸坯裂纹产生的原因:铸坯深振痕和大量析出物形成裂纹源,并且铸坯在流道处于脆性区且受应力过大。提出了控制板坯网状裂纹的有效措施,包括减少典型元素含量、适当提高并稳定铸机拉速、采用改进的连铸保护渣、减弱结晶器和二冷强度,提高流道质量等。相关技术措施通过大量的现场应用,减轻了低合金钢板坯网状裂纹缺陷,热轧板卷起层缺陷率由21.84%降至0.47%。
The star cracks are hidden in the subsurface of continuous casting slab,which are difficult to be detected in manual on-line inspection,and it is easy to cause a large number of peeling defects when the burning loss of heating furnace is insufficient.Through metallographic analysis of rolled piece and slab,it is clear that the cause of defects comes from star cracks of the slab.In view of the star crack of the slab using the full-arc continuous casting machine,the influences of typical elements(C,Al,N,V),cooling intensity of mold,slag in the continuous casting,secondary cooling strength and others on the crack defects of casting slab were analyzed.The causes of the cracks in casting slab were clarified that deep vibration marks and a large amount of precipitates form the crack initiation,and the slab is located in the brittle zone in the caster and suffers excessive stress.The effective measures to control the cracks are put forward,including reducing the contents of typical elements,increasing and stabilizing the casting speed,employing improved continuous casting slag,weakening the mold strength and secondary cooling strength,improving the quality of caster,etc.After a large number of actual applications,the crack defects of low alloy steel slab are reduced,and the peeling defect rate of hot-rolled plate is reduced from 21.84%to 0.47%.
作者
黎建全
高琦
姜银昌
吴国荣
周明佳
谢鑫
LI Jianquan;GAO Qi;JIANG Yinchang;WU Guorong;ZHOU Mingjia;XIE Xin(Vanadium Recovery&Steelmaking Plant,Pangang Group Steel and Vanadium Co.,Ltd.,Panzhihua 617062,Sichuan,China;Metallurgical Equipment Research Institute,China National Heavy Machinery Research Institute Co.,Ltd.,Xi’an 710018,Shaanxi,China;PanGang Group Panzhihua Iron&Steel Research Institute Co.,Ltd.,Panzhihua 617000,Sichuan,China)
出处
《连铸》
北大核心
2024年第5期98-104,共7页
Continuous Casting
关键词
连铸板坯
网状裂纹
低合金钢
钢种特性
冷却工艺
continuous casting slab
star crack
HSLA steel
steel property
cooling process
