Method for reducing broken edge defect of Q355B steel coil of thin slab continuous casting and rolling production line

The invention provides a method for reducing a broken edge defect of a Q355B steel coil of a thin slab continuous casting and rolling production line. The method comprises the following steps: determining a secondary cooling curve according to a steel type and a pulling speed, wherein the pulling speed is 3.8 to 4.5 m/min; and carrying out thin slab continuous casting on molten steel, and settinga secondary cooling modification coefficient in the secondary cooling curve according to at least one of the thickness of a crystallizer copper plate, the titanium content of steel, the superheat degree, the section width of the steel and the acid-soluble aluminum content in the steel. According to the method for reducing the broken edge defect of the Q355B steel coil of the thin slab continuous casting and rolling production line, the precipitation mechanism of TiN in a Ti-containing steel grade is adopted, the secondary cooling correction coefficient in the continuous casting process is adjusted according to the rel