Mechanism of edge crack formation in AISI304L steel during hot rolling

In this study, the effect of delta ferrite formation and segregation of alloying elements on the mechanism of edge cracking on the surface of AISI304L stainless steel during hot rolling in Iran Alloy Steel Company was evaluated. For this purpose, scanning electron microscopy (SEM) with two detectors, SE and BSE, and EDX analysis were used to examine the areas around the crack. The results was shown that the tendency to create edge cracks during hot rolling increases with enhancement delta ferrite content and the mechanism of crack growth is along the delta ferrite and the delta ferrite/ austenite interface. SEM studies of the crack-containing specimens in showed the number of micro-cracks in the areas around the main crack and the presence of worm-shaped delta ferrites and delta ferrite islands in the austenitic matrix. In addition, the segregation of the copper element also plays an important role in creating cracks in the surface of AISI304L stainless steel ingots during hot rolling.