| 摘要 |
PROBLEM TO BE SOLVED: To provide a manufacturing method and manufacturing apparatus for an aluminum alloy base for a planographic printing plate for obtaining an alloy cast sheet of stable quality having a uniform and fine cast structure. SOLUTION: This method has a casting process step of supplying molten alloy between cooling rollers through a molten metal supply nozzle, a casting process step of forming a continuously cast slab, a rolling process step of forming the alloy sheet of a prescribed thickness by subjecting the continuously cast slab to cold rolling treatment and a surface roughening treatment process step of subjecting the surface of the alloy sheet to surface roughening treatment. Casting is performed under the conditions under which the relations among the peripheral speed of the cooling rollers, defined as V (m/min), the thickness of the continuously cast slab, defined as t (m) and the diameter of the cooling rollers, as D (m), satisfy the equation; V>=5×10-5×(D/t2) (m/min). The outer periphery in the mouth of the molten metal supply nozzle is preferably recessed with a clearance to evade the contact with the cooling rollers. |
