酸洗汽车结构钢表面色差成因探究及工艺优化

Study on the Cause of Surface Color Difference of Pickling Automobile Structural Steel and Process Optimization

针对酸洗汽车结构钢SAPH370表面出现的下表面条带状色差缺陷,通过光学显微镜、扫描电镜分析缺陷热轧基板氧化铁皮结构及酸洗后微观形貌可知,带钢表面粗糙度差异是造成表面色差的直接原因。结合热轧辊表面状态可知,下表面条带状色差缺陷产生的主要原因是精轧工作辊下辊比上辊辊面氧化膜剥落更严重,辊面状态的差异遗传至热轧基板,最终造成酸洗后表面粗糙度差异。通过优化轧制温度、轧辊换辊周期及轧制润滑工艺等,可以有效消除色差缺陷。

According to the strip color difference defect on the surface of pickling automotive structural steel SAPH370,the structure of the oxide sheet of defective hot-rolled substrate and the micro-morphology after pickling were analyzed by optical microscope and scanning electron microscope,and it was found that the difference of strip surface roughness was the direct cause of the surface color difference.Combined with the surface state of the hot roll,it can be seen that the main reason for the strip color difference on the lower surface of the finishing roll is that the oxidation film on the lower roll is more serious than that on the upper roll,and the difference in the state of the roll is inherited to the hot rolled substrate,resulting in the difference in surface roughness after pickling.The defects of color difference can be effectively eliminated by optimizing the rolling temperature,roll change period and rolling lubrication technology.