Exfoliation of surface oxide from continuously cast copper bar in

Abstract

A method is provided for removal of surface oxide from a continuously cast copper bar preparatory to inline hot rolling, wherein solidified bar continuously advancing from a continuous caster is directed to a continuous hot rolling mill, comprising: passing said advancing bar, being at hot rolling temperature, through a spray zone of selected quench capacity and impulse, such that for each segment of said bar passing through said spray zone, said oxide is quenched to a black heat but is not ablated and said underlying bar is subjected to a shallow quench; said spray zone being situated in close proximity to but selectively spaced upcourse from the first rolls of said hot rolling mill such that there is insufficient time for substantial reheating of said quenched oxide during the approach to said first rolls; whereupon as quenched segments of the advancing bar progressively approach said first rolls and said underlying bar begins to deform just prior to roll contact, said oxide spalls off the bar surfaces substantially. Thus, the protective copper oxide is not removed from the bar surface until immediately prior to roll contact thereby preventing reoxidation of the bar surface; and further, since the spray is necessarily nonablative in magnitude there is minimal effect on the temperature and hot forming characteristics of the underlying bar.