冷轧宽厚规格深冲钢梗印缺陷成因分析及其控制措施

针对山东钢铁集团日照有限公司2 030 mm冷轧产线宽厚规格深冲钢卷出现大量梗印缺陷问题,通过现场实测与多功能仪自动检测相结合检测缺陷卷热轧卷横断面轮廓曲线,检测热轧卷微观组织及硬度等方法,分析了梗印缺陷的形成原因。结果表明:带钢横断面存在连续局部高点,卷取中局部高点逐层累加形成鼓包,因深冲钢屈服强度较低,成卷后局部高点处存在应力集中,使其沿径向和横向发生延展变形而导致梗印缺陷的形成,且梗印缺陷卷开卷后在带钢边部形成浪形。为此,在热轧工序通过优化轧辊轴向横移、弯辊策略以及调整轧制节奏等措施,增大工作辊辊缝凸度,从而有效改善热轧带钢横断面局部高点缺陷,为冷轧工序提供合格原料。在冷轧工序通过优化工作辊辊缝形状、分小卷卷取等措施,宽厚规格深冲钢的局部高点可得到有效控制,显著降低了因梗印缺陷造成的不良改判率。

Cause analysis of stem seal defects of cold rolled wide and thick gauge deep drawing steel strip and its control measures

Aiming at the problem of a large number of stem seal defects of deep drawing coil in 2 030 mm cold rolling line of Rizhao Co., Ltd.of Shandong Iron and Steel Group, combination of on-site measurement and automatic detection of multi-function instrument to detect the cross-sectional profile curve of hot rolled defect coil and its microstructure and hardness, the cause of this defect was analyzed.The results show that there is a continuous local high point in the cross section of the strip, and the local high points in the coiling accumulate layer by layer to form a drum bag, because the yield strength of deep drawing steel is low, and there is stress concentration at the local high point after coiling, which leads to the formation of the stem seal defects, and the edge wave shape of strip forms after un-coiling.For this reason, some measures of optimizing the roll axial shifting amount, bending strategy and adjusting the rolling rhythm in the hot rolling process were applied, so as to effectively improve the local high point defect of the cross section of the hot rolled strip and provide qualified raw materials for the cold rolling process.In the cold rolling process, by optimizing the roll gap shape of the work roll, dividing the small coils and other measures, the local high point of the wide and thick gauge deep drawing steel strip can be effectively controlled, and the bad correction rate caused by stem seal defects is significantly reduced.