An apparatus for treating a surface of a strip casting twin roll includes: a laser machining unit configured to form dimple patterns on a surface of a rotating casting roll using a laser; a machining region processing unit, wherein if the casting roll is rotated by a critical angle, the machining region processing unit calculates a size and a position of a machining region, in which a dimple pattern will be formed, based on image information obtained by imaging the machining region; and a laser beam absorbing unit, wherein if the size of the machining region is smaller than a size of the dimple pattern, the laser beam absorbing unit places a screen at an overlap start position from which the machining region and the dimple pattern start to overlap each other, so as to absorb a laser beam emitted toward a peripheral region of the machining region.

A rotary roller surface cleaning method and a rotary roller surface cleaning apparatus which, when foreign matter is detected on a surface of a rotary roller of a quenched ribbon manufacturing apparatus, remove the foreign matter by irradiating the foreign matter with a laser having an output value corresponding to a thickness of the foreign matter. At least one of a rotation speed of the rotary roller and a laser response time is adjusted such that the rotation speed of the rotary roller and the laser response time satisfy a relational expression VSD/1000 (D0.1 mm), where the rotation speed of the rotary roller is V (m/sec), the laser response time is S (sec), and a length of the foreign matter along a circumferential direction of the rotary roller is D (mm).

A twin-roll strip caster includes: a pair of casting rolls rotating in opposite directions to each other, and having an edge dam adhering to both end surfaces of the casting rolls in a length direction of the casting rolls; a submerged nozzle discharging molten steel between the pair of casting rolls; a meniscus shield disposed above the molten steel supplied through the submerged nozzle to prevent the molten steel from contacting air; and a focused gas supply nozzle disposed between the submerged nozzle and the meniscus shield to supply inert gas therebetween so as to displace air between the submerged nozzle and the meniscus shield before the molten steel is supplied.

An apparatus for treating a surface of a strip casting twin roll includes: a laser machining unit configured to form dimple patterns on a surface of a rotating casting roll using a laser; a machining region processing unit, wherein if the casting roll is rotated by a critical angle, the machining region processing unit calculates a size and a position of a machining region, in which a dimple pattern will be formed, based on image information obtained by imaging the machining region; and a laser beam absorbing unit, wherein if the size of the machining region is smaller than a size of the dimple pattern, the laser beam absorbing unit places a screen at an overlap start position from which the machining region and the dimple pattern start to overlap each other, so as to absorb a laser beam emitted toward a peripheral region of the machining region.