Research and control of straight cracking after slab rolling

Aiming at the problem of linear edge cracks on steel plates occurring in Hunan Valin Xiangtan Iron and Steel Co., Ltd., the crack morphology was observed via an optical microscope. It is confirmed that the defect is induced by surface folding during the rolling process, rather than the inheritance of cracks from continuous casting billets. The effects of key factors including the narrow face profile of casting billets, rolling widening ratio, and the temperature difference between the upper and lower surfaces of billets before rolling were comparatively analyzed through rolling tests. The optimization of rolling process parameters and the development of convex crystallizers and matching foot rolls have effectively controlled the linear edge cracks of steel plates.