CAST TITANIUM SLAB FOR USE IN HOT ROLLING AND EXHIBITING EXCELLENT SURFACE PROPERTIES AFTER HOT ROLLING, EVEN WHEN OMITTING BLOOMING AND PURIFYING STEPS, AND METHOD FOR PRODUCING SAME

摘要

A cast titanium slab for use in hot rolling and comprising industrial pure titanium or a titanium alloy, wherein a surface serving as the rolling surface has a fine-structure layer comprising a needle-shaped structure formed on the outermost surface by a melting-resolidifying treatment, and the thickness of the fine-structure layer has a depth of at least 5mm and less than 9mm. This cast titanium slab for use in hot rolling has a flat surface, has few micropores in the interior directly below the surface, and has an outermost surface exhibiting an extraordinarily fine structure. Thus, when used in hot rolling, it is possible to stably prevent, at a practical level, the occurrence of concavities in the surface during the initial hot rolling stage and the occurrence of surface defects in a rolled plate.