Continuous casting method for producing round blank with diameter larger than Phi800m on straight continuous casting machine

The present invention relates to a continuous casting method for manufacturing a round billet with diameter being more than or equal to Phi 800 mm on a straight continuous casting machine, which includes the following manufacturing process: molten steel from the steel converter is poured into a ladle and rotated to the upper part of a tundish through a ladle turret, molten steel flows into a crystallizer, and covering slag on the surface of the crystallizer mainly comprises the following components by the weight percentages: 26-32 percent of SiO2, 14-18 percent of Al2O3, 24-28 percent of CaO, 16-20 percent of C and 2-4 percent of Li2O. When a billet shell at the outlet at the lower end of the crystallizer has a certain thickness, and a tension leveler and a crystallizer vibration device are turned on, the round billet with a liquid core is slowly pulled out downwards, 4-8 m length round billets are cut through a flame cutting machine, the excised round billets are horizontally positioned and pulled out, the length round billets over 600 DEG C surface temperature are hung to a slow cooling pit for slow-cooling over 24 hours, and the round billets after finishing slow cooling is hung to a shot blasting machine for shot blasting examination of the surface. The continuous casting method can compensate for the large shrinkage generated during casting and solidification and solve the stress problem generated during the cooling process.