CONTROLLING METHOD FOR SURFACE QUALITY OF ULTRA LOW CARBON STEEL SLAB

摘要

The present invention relates to a method for controlling the surface quality of an ultra low carbon steel slab which is capable of controlling the quality of a slab by minimizing surface defect generated in an ultra low carbon steel slab. Provided is the method for controlling a surface quality of an ultra low carbon steel slab comprising: a step for observing a hook structure inside each slab which has been manufactured by adding a phosphorus content for improving strength to a molten steel for manufacturing an ultra low carbon steel slab while changing the phosphorus content; a step for calculating a hook depth (HD) which indicates a lineal distance from a coagulation shell surface to a hook end through a hook slope (D) which is the angle between a hook structure and a slab surface, and a hook length (L) which is the overall length of a hook structure inside each observed slab; a step for calculating the optimum phosphorus containing area where the slab strength is improved and the hook depth is decreased, through the calculated hook depth; and a step for continuous casting of the slab for controlling the phosphorus content inside the molten steel when an ultra low carbon steel slab is manufactured in the calculated optimum phosphorus containing area. [Reference numerals] (AA) START; (BB) END; (S10) Observe a hook structure inside an ultra low carbon steel slab which changes a phosphorus content; (S20) Calculate a hook depth through a hook slope and a hook length of the hook structure; (S30) Calculate the optimum phosphorus containing area where the hook depth is decreased; (S40) Manufacture the ultra low carbon steel slab by controlling the phosphorus content inside the molten steel