BRIGHT STEEL SHEET AND ITS PRODUCTION

摘要

PURPOSE:To produce a bright steel sheet which is highly resistant to flawing by forming many craters of specific sizes by using a high-density energy source on the surface of a work rolls subjected to bright finishing, then subjecting a cold rolled steel sheet to temper rolling. CONSTITUTION:The surface of the work roll is subjected to the bright finishing to <=0.35mum surface roughness Ra by polishing. The high-energy source such as laser beam is then projected to such surface to regularly form the many craters thereon. The craters are bored to 5-50mum depth so that the value of Sm/D attains 1<=Sm/D<=5 when the spacing between the adjacent craters is designated as Smmum and the diameter of the respective craters as Dmum. The cold rolled steel sheet after cold rolling and annealing is then subjected to temper rolling by using the work roll. The bright steel sheet which has the surface shape consisting of the smooth part having <=0.40mum surface roughness Ra and the many projections transferred from the surface shape of the above-mentioned work roll is thereby obtd.