The edge-cracking of AISI 304 stainless steel during hot-rolling

The hot-rolled plates of AISI 304 stainless steel, containing edge cracks of different intensities, were examined. The austenitic matrix of the steel contained small amounts of δ ferrite inhomogeneously distributed across the width and the thickness of the plate. A correlation was found between ferrite content and edge cracking: the higher the ferrite content the longer the edge cracks. Among the chemical elements present in the steel, the most critical effect on δ ferrite content was exerted by carbon and nitrogen. The longest edge cracks were observed for plates with the lowest content of carbon and nitrogen. A possible contribution of steel chemistry and heating temperature to changes in the steel phase composition and the probability of edge cracking is discussed.