METHOD FOR MANUFACTURING HOT ROLLED IF STEEL WITH EXCELLENT WORKABILITY AND VARIATION OF MECHANICAL PROPERTY

摘要

PURPOSE: A method for manufacturing hot rolled IF steel is provided to obtain excellent workability of hot rolled IF steel and reduce the variation of mechanical property in both lateral and longitudinal directions. CONSTITUTION: A method for manufacturing hot rolled IF(Interstitial Free) steel comprises a continuous casting step, a finish rolling step, a coiling step. In the continuous casting step, steel is casted at a casting speed of 4.5 mpm or greater. In the finish rolling step, a finish rolling mill(50) implements finish rolling in a ferrite region with an entrance temperature of 930C or less and an exit temperature of 750-850C. In the coiling step, slab is coiled at a temperature of 650-730C.