Hot rolled law carbon steel plate manufacturing method for surface scale and workability excellent

摘要

PURPOSE: A method for manufacturing hot rolled low carbon steel having superior surface scale and formability by properly controlling heating time and extracting temperature in heating furnace, the number of rough rolling passes and extracting temperature in rough rolling, heating the edge of strip, and proceeding speed and descaling in finish rolling is provided. CONSTITUTION: In a slab comprising 0.02 to 0.05 wt.% of C, 0.10 to 0.30 wt.% of Mn, 0.20 wt.% or less of P, 0.020 wt.% or less of S and a balance of Fe and inevitable impurities, the method for manufacturing hot rolled low carbon steel having superior surface scale and formability comprises the processes of heating the slab in such a way that a heating furnace extracting temperature is maintained to 1,150 to 1,220 deg.C; rough rolling the heated slab in a rough rolling mill in such a way that a rough rolling extracting temperature is maintained to 1,000 to 1,200 deg.C; heating the edge of the rolled strip so that temperature of central part and both edge parts of the rolled strip is uniformly maintained; water cooling the edge heated strip; finish rolling the water washed strip in a finish rolling mill at a proceeding speed of 640 to 68 m/min in such a way that an outlet temperature of the finish rolling is maintained to 850 to 900 deg.C, wherein the slab is heated for 180 to 220 minutes in the heating furnace, wherein the number of R2 rough rolling passes of the rough rolling mill is 3, wherein the edge heated strip is water cooled by operating any one sprayer in two sprayers before advancing the water washed strip into the finish rolling mill, and wherein descaling is performed on the water washed strip while cooling water is not sprayed onto the water washed strip during the finish rolling.