冷轧Q195L钢带鱼鳞状掉皮缺陷成因分析  

Analysis of Flakes Peeling on the Surface of Cold-rolled Strip Steel

作　　者：赵新凯[1] 孙本良[1] 李长友[1] 韩朝霞[1] 

机构地区：[1]唐山建龙实业有限公司,河北唐山064200

出　　处：《过程工程学报》2010年第4期706-713,共8页The Chinese Journal of Process Engineering

摘　　要：结合SEM及EDS、金相分析、数值模拟方法研究了冷轧Q195L钢带冷轧过程中出现的鱼鳞状掉皮现象.试样检测表明,非金属夹杂物和氧化铁共同作用导致这种缺陷,前者来源于钢水夹杂驱除不净或保护渣卷渣,后者根源在于连铸坯内部裂纹发生脱碳氧化,最终在冷轧中暴露于表面.数值模拟表明,铸坯角部裂纹发生在结晶器内,钢水开始浇注的前6s内铸坯角部降温速率为124.9℃/s,凝固收缩速率达0.07mm/s.凝固前裂纹指数呈增长趋势,在凝固末端达0.75,伴随疏松与缩孔形成中心裂纹;凝固坯壳内从近表面到距离边部41mm处裂纹指数均出现过大于1的情况,中间裂纹形成于此,铸坯二冷II段内回温会导致中间裂纹沿弱化的柱状晶晶界扩展.SEM,EDS and metallographic microscope were been used to study flakes peel-like defects on the surface of cold-rolled strip steel combined with mathematical simulation.The analytical results show that the flakes peeling was induced by non-metallic inclusions and scales.Inclusions could be derived from steel de-oxidation or slag entrapment,and scales,initiating cracks inside billet,which could be exposed to the surface on cold-rolling process,were caused by de-carbonization because of improper heating mode or time.Numerical simulation shows that after pouring within the first 6 s,temperature dropped to 124.9℃/s and solidified shrinkage rate to 0.07 mm/s,that makes corner cracks.Crack index of solidified front increased up to 0.75 at the end of solidification,with formation of porosity and shrinkage cavity.Crack index was over 1 near the surface from the edge to 41 mm thickness,where middle cracks formed.Temperature rally in the secondary cooling zone II resulted in extension of middle cracks along columnar grain boundary.

关 键 词：冷轧钢带 鱼鳞状掉皮 金相 数值模拟 回温 

分 类 号：TG113.1[金属学及工艺—物理冶金]