Method and apparatus for removing scale from hot-rolled steel strip

A method for continuously removing scale from a hot-rolled carbon steel strip, the method comprising:

• cracking the scale on the hot-rolled steel strip, wherein the cracking is carried out using a scale breaker, and wherein an elongation and an amount of bending of the scale breaker in the cracking are controlled to 0.5-3% and 10-50 mm, respectively;
• shot-blasting the cracked scale to remove the scale, wherein an amount of scale removed in the shot-blasting is 80-95% of a total amount of scale to be removed, wherein a shot ball diameter, a shot ball sprag speed and an amount of shot balls sprayed in the shot-blasting, are controlled to 0.3-0.8 mm, 60-78 m/sec, and 800-1200 kg/min, respectively;
• deforming the hot-rolled steel strip so as to weaken the bond between scale remaining after the shot-blasting and the hot-rolled steel strip and so as to impart surface roughness to the hot-rolled steel sheet, wherein the deforming of the hot-rolled steel strip is carried out using a skin-pass roller;
• and
• polising the deformed hot-rolled steel strip to remove the remaining scale, wherein the polishing is carried out using a plurality of rotatable brush rolls, wherein a roughness of the brush rolls in the polishing is #100˜#240 on a mesh number basis, and wherein a revolution speed of the brush rolls is controlled to 600-1200 rpm.