COOLING DRUM FOR CONTINUOUSLY CASTING THIN CAST PIECE AND FABRICATING METHOD AND DEVICE THEREFOR AND THIN CAST PIECE AND CONTINUOUS CASTING METHOD THEREFOR

摘要

An object of the present invention is to realize a technology enabling a thin slab to be stably cast over a long period of time by simultaneously suppressing the generation of surface cracks and uneven luster, two major types of defects in a sheet product explained as problems in conventional technologies, and the present invention provides a method of processing a cooling drum for metal cast strip by continuous casting and an apparatus therefor. According to the present invention, a method of processing a cooling drum for metal cast strip by continuous casting by processing the peripheral surface of the cooling drum used for continuously casting a thin slab is characterized in that: when fine holes 50 to 200 mu m in diameter and not less than 50 mu m in depth are formed so as to have the pitch of, 100 to 500 mu m but not to contact each other by irradiating Q-switched CO2 laser light to the surface layer of the cooling drum, the pulse energy of Q-switched CO2 laser light is 40 to 150 mJ, total time span is 30 to 50 mu sec and the condensed diameter of the laser beam is 50 to 150 mu m.