DC03冷轧基料表面氧化铁皮针孔缺陷的形成机理及控制

Formation mechanism and control of pinhole defects of oxide scale on the surface of base material for cold rolling of DC03

针对某企业在生产DC03冷轧板过程中,其热轧带钢酸洗后表面出现氧化铁皮针孔缺陷的问题,结合现场开展了理论和实验研究工作。首先对现场实物进行取样分析,认为在精轧过程中氧化铁皮被压入到带钢表面是造成氧化铁皮针孔缺陷形成的主要原因。为了进一步探究这一缺陷的形成机制,在实验室对DC03钢进行了温度为830~1080℃的氧化动力学实验和氧化铁皮高温变形实验。结果表明:该钢的氧化激活能较低,在精轧温度范围内容易产生较厚的氧化铁皮,而且随着温度的升高,氧化铁皮中FeO所占比例提高,氧化铁皮的塑性改善。当精轧温度较低时,氧化铁皮破碎严重,氧化铁皮很容易被压入到基体中,形成氧化铁皮针孔缺陷,而随着轧制温度的升高,氧化铁皮的塑性逐步改善,当达到一定温度时,氧化铁皮能很好地随基体变形,使氧化铁皮保持相对较好的完整性。基于上述研究结果,针对现场实际,提出了适当提高轧制速度和严格控制终轧温度等改进措施,氧化铁皮的厚度及塑性得到有效控制,彻底消除了DC03冷轧基料氧化铁皮针孔缺陷。

In view of the problem of pinhole defect of oxide scale appeared on the surface of the hot rolled strip after pickling of producing DC03 cold rolled sheet in an enterpris,theoretical and experimental research was carried out in combination with the field.Firstly,it is concluded that the pinhole defects of the oxide scale are mainly caused by the fact that the oxide scale is pressed into the strip surface during the finishing rolling.In order to further explore the formation mechanism of this defect,the oxidation kinetics experiment of DC03 was carried out in the laboratory at the temperature of 830-1080℃.The results showed that the oxidation activation energy of the DC03 steel was low,and it was easy to produce thicker oxide scale in the finishing rolling temperature range.Moreover,the proportion of FeO in the oxide scale increased with the increase of temperature,and the plasticity of the oxide scale was improved.When the finishing rolling temperature was low,the oxide scale was broken seriously,and the oxide scale was easily pressed into the matrix,forming the pinhole defect of the oxide scale.However,the plasticity of the oxide scale was gradually improved with the increase of the rolling temperature.When the temperature reached a certain level,the oxide scale could be well deformed with the matrix,so that the oxide scale could maintain a relatively good integrity.Based on the above research results,some improvement measures were put forward to improve the rolling speed and strictly control the finishing rolling temperature.The thickness and plasticity of the oxide scale were effectively controlled,and completely eliminate thepinhole defect of oxide scale of base material for cold rolling of DC03.