Longitudinal buckling behavior in temper rolling of thin steel strips with delivery angle

Abstract

Abstract. The shape defect referred to as "longitudinal buckling" or “longitudinal buckle” tends to occur in temper rolling of double-reduced thin strips. In our previous study, we carried out an experiment to investigate the effect of the delivery angle on longitudinal buckling, and showed that longitudinal buckle completely disappears when the delivery angle exceeds a certain angle. The change of the buckling mode (number of longitudinal buckles) depending on the delivery angle calculated with a buckling model of a flat plate with curvature agreed with the experimental results under the condition of a delivery angle over 10°, but not under the condition of 10°. In this paper, it was found that the experimental results for the delivery angle of 0° could be explained by the Komori model, which assumes flat plate buckling of a length corresponding to the roll bite length. A FEM analysis of the limit buckling stress assuming constraint by the work roll proved that the limit buckling stress was larger than the estimated widthwise stress, indicating that initiation of buckling did not occur in the winding part on the work roll. On the other hand, a rolling experiment revealed that the buckling shape of many micro-waves generated near the roll bite could change in the winding part. These results suggest that longitudinal buckling begins around the roll gap and varies with the shape of the sheet wrapped around the work roll.