| 摘要 |
PURPOSE:To relieve thermal stress and to extend the life of a roll by engraving spiral grooves to the roll surface, fixing bellows having many nozzle holes to the inside of the grooves to close the grooves and providing a water feed hole and discharge hole communicating with the hermetic water passages of the roll to both ends of the grooves in the axial direction of the roll. CONSTITUTION:The roll 1 is made into the construction in which the spiral grooves 5 are provided to the roll surface and in which the water feed hole 6 and discharge hole 6a communicating with the cooling water hole 4 at the roll center are provided to both ends of the grooves. The bellows 8 having the many nozzle holes 7 are welded to the grooves 5 to close the open parts of the grooves 5, thereby constituting the hermetic passages to the roll surface. The bellows 8 are made freely expandable and shrinkable to absorb the thermal expansion of the roll 1 and are attached in the position lower than the roll 1 surface to prevent the contact with a billet. The bellows 8 are made of a stainless steel in consideration for corrosion resistance. |
