| 摘要 |
PURPOSE:To prevent spalling even a roll is used as a work roll in skin pass rolling for a galvanized steel sheet by applying chrome plating in a specific condition onto the surface of a rolling roll made of steel. CONSTITUTION:A chrome plating whose layer thickness is 1-30mum and hydrogen content in the layer is <10ppm is applied to the surface of a rolling roll made of steel. The layer of chrome plating effects crack generation; in the case a layer of <1mum, a remaining layer thickness is mostly lost in a long period rolling and a service life before crack generation is short and a layer exceeding 30mum may disturb surface roughness of a roll before plating by shot blasting or may generate plating layer breakdown at strong drafting. If a hydrogen content in a layer after dehydrogenation treatment remains to exceed 10ppm, effects preventing generation of spalling decrease. Therefore, crack generation on the roll surface caused by rolling is completely eliminated and spalling is prevented. |
