展宽变形均匀化对厚板边部线状裂纹缺陷的改善

Improvement of straight edge seam defect on heavy plate through unifying the deformation of width spread

边部线状裂纹在厚板产线属于常见缺陷,国内外很多厚板研究机构均对此类缺陷做过研究。通过大生产数据分析和金相组织分析,对部分研究的理论机理进行了验证:轧制过程中,板坯侧面靠近板坯轧制上下表面处首先形成凹陷,而后凹陷随侧面翻平过程到达轧制表面形成折叠,即边部线状裂纹。展宽轧制过程上下表面的不均匀变形会增加边部线状裂纹距钢板边缘的距离。通过试验轧机模拟寻找到了均匀化上下表面变形来减少翻平的措施,并结合缺陷的产生机理在大生产中进行了改进。

Straight edge seam defect is one kind of common defect but difficult to control in heavy plate production lines,although there are many studies have been done.Through a large amount of production data analysis and metallographic analysis,the theoretical mechanism of some previous studies was verified.During the rolling process,a depression is first formed on the side of the slab which is near the top or bottom surfaces,and then the depression comes to the rolling surface with the metal flow process of both sides,thereby forming a long fold,which is called a linear crack at the edge.In subsequent broad-sizing rolling stage,the difference deformation between the top and bottom surfaces increases the distance of the linear crack from the edge of the plate.Using the pilot mill simulation,the measures to reduce the defects by homogenizing the surface deformation are found.So far,combining the mechanism of defects,the process has been improved in production line.