Effect of Charging Process on Properties of Steel Plates Formed via Hot-Core Heavy Reduction Rolling

The hot-core heavy reduction rolling (HHR 2 ) process makes use of the reverse temperature gradient of casting steel to eliminate the inner shrinkage and porosity defects during continuous casting. As the key connecting process between continuous casting and rolling, the charging process affects the microstructure evolution of workpiece rolled by HHR 2 process. The direct rolling and hot-charging experiments were carried out for the workpieces rolled by HHR 2 process, to investigate the effects of charging process on the microstructure and mechanical properties of hot-rolled steel plate. For comparison, the conventional cold-charging experiments were also performed on the workpiece without HHR 2 . The results show that the similar microstructures and mechanical properties can be obtained from the hot-rolled plates produced from the workpieces rolled by HHR 2 , which were followed by direct rolling or hot-charging process, as well as that of hot-rolled plate produced from the workpiece without HHR 2 via cold-charging process. Moreover, the microstructure and mechanical properties at the core of the hot-rolled plate via direct rolling process are better than those without HHR 2 . It indicates that the γ-α-γ reciprocating phase transformation, which occurs during the cold-charging process, can be replaced by deformation recrystallization that occurs during the HHR 2 process, to refine austenite grains.