高合金冷轧带材表面起皮缺陷分析

Surface peeling defect of high alloy cold rolled steel strip

高合金冷轧带材表面通常出现两种类型的起皮缺陷,会显著降低带材的成材率。借助金相显微镜及电子探针对不同类型起皮缺陷的微观组织进行了形貌观察和成分分析,结合连铸工艺参数的研究,分析了高合金冷轧带材表面起皮缺陷的原因。结果表明,由于连铸结晶器内部温度场不均匀产生热应力或坯壳厚度不均匀,从而导致铸坯表面或皮下产生裂纹,经冷轧加工后即形成第一种类型的起皮缺陷;或是由于连铸过程中保护渣被卷入钢液,在连铸坯上形成皮下夹渣,经冷轧加工后便形成第二种类型的起皮缺陷。通过调整和改进连铸工艺,大大降低了起皮缺陷的发生率。

High alloy cold rolled strips usually have two types of surface defects which result in a significantly decreased on the yield of strips. With the help of microstructure morphology and electron probe, different types of defects were analyzed. Combining with continuous casting parameters, the reason for surface defects were identified. The results showed that uneven temperature of the mold was the main reason for type I defect. It caused a thin slab region with high stress and lead to subsurface crack. After cold rolling, it would appear in the product＇ s surface. Also slag may be involved into the continuous casting billet. It would cause the type Ⅱ defect. By the adjustment and improvement of continuous casting process, the incidence of surface peeling defect was greatly reduced.