氧化铁皮在冷轧过程中的断裂行为

Fracture Behavior of Surface Oxide Scale in Cold Rolling

利用轧卡实验研究热轧低碳钢表面氧化铁皮在无酸洗冷轧过程中的断裂行为.结果表明,由于带钢在靠近辊缝处的弹性变形,带钢表面的氧化铁皮受拉应力作用发生断裂,裂纹垂直于轧制方向,越靠近辊缝裂纹密度越大.单道次轧制压下量小于16%时,氧化铁皮只发生断裂;压下量超过16%时,氧化铁皮开始出现脱落,当氧化铁皮受力超过其界面附着强度时,将发生氧化铁皮从带钢表面剥离和粉碎.同样的总压下量条件下,多轧制道次有利于保护氧化铁皮的完整性.

The fracture of oxide scale on the hot-rolled low carbon steel strip in cold rolling without pickling was investigated.It is found that micro-cracks were formed in the oxide scale near the entry to the roll bite due to the elastic deformation of the steel strip near the gap of the rolls,running perpendicular to the rolling direction.Density of cracks increased with the distance closer to the bite entry.The oxide scale was cracked only with the reduction of single pass lower than 16%,while the reduction of single pass was higher than 16%,the oxide scale began to spall.When the interface shear stress was beyond the adhesive strength between the oxide scale and the steel surface,spalling and powdering of the oxide scale from the surface of the steel strips will occur.Under the same total reduction condition,the multi-pass rolling is favor to protect the integrality of the oxide scale.