Initiation mechanism on transverse microstructure and properties inhomogeneity of hot-rolled low-carbon steel plate

The center and edge of the hot-rolled low-carbon steel plate reflect the inhomogeneity. Five positions along the transverse direction of the steel plate are taken as the research object. This study reveals the root cause of the inhomogeneity of transverse microstructure and properties of hot-rolled low-carbon steel plates. The grain size in the center of the hot-rolled low-carbon steel plate is relatively large, and the grain size at the edge is relatively small. The mechanical properties test shows that the closer the edge, the higher the hardness. The strength along the transverse direction is similar to the shape of W. The finite element simulation results show that the central cooling is slow, and the deformation degree is different in different transverse positions. In conclusion, the main reason for the inhomogeneous microstructure are the various cooling rates of different parts in the transverse direction. The synergistic effect of grain size and alloying elements is the main reason that causes the transverse strength distribution to show a "W" shape.