System and method for preventing scale defects during hot rolling

A system and a method are disclosed for preventing scale defects during hot rolling by hot rolling equipment having a scale breaker (FSB) provided at an entry side of a finishing mill line (F) composed of a plurality of rolling mills (F1 to F7) arranged in tandem. A descaler (D) is provided between a first stage rolling mill (F1) and a second stage rolling mill (F2) of the finishing mill line (F). A cooler (C) for cooling a hot rolled steel plate 1 is provided between the second stage rolling mill (F2) and a third stage rolling mill (F3) of the finishing mill line (F). A control device (8) is provided for controlling the descaler (D) and the cooler (C) to be selectively driven such that neither of the descaler (D) and the cooler (C) is actuated, one of the descaler (D) and the cooler (C) is actuated, or both of the descaler (D) and the cooler (C) are actuated, according to rolling conditions. Thus, the hot rolled steel plate 1 is rolled, with its oxide film thickness at an entry side of the third stage rolling mill (F3) being restricted to not more than a limiting oxide film thickness of 5 mu m. Consequently, scale defects are prevented, and overcooling of the hot rolled steel plate 1 is suppressed, to improve the quality of a product.