Cooling method of continous casting

Abstract

A cooling mold having first and second water cooling jackets which are provided inside the mold, a primary cooling water jetting mouth which is located at a distance of 15 to 40 mm from a meniscus of the molten metal, and a secondary cooling water jetting mouth which is located at a position with an interval of 20 to 45 mm between a contact point of a primary jet of cooling water and another contact point of a secondary jet of cooling water on an ingot. By use of the cooling mold having the primary and secondary cooling water jetting mouths which are respectively set at an angle of 15 to 30 degrees and of 30 to 60 degrees relative to the ingot surface, the primary jet of cooling water from the primary mouth impinges on the molten metal cooled in the cooling mold at a short distance from the meniscus to establish a transition boiling zone and a film boiling zone, and then, the secondary jet of cooling water from the secondary mouth impinges on initial zones of the transition boiling zone and the film boiling zone to break-out a vapor film generated in the initial zones so as to provoke a nucleate boiling and thereby to produce a firmer solidified shell in the ingot, whereby the ingot can be properly and effectively cooled without danger of breakout so that stable high rate casting and a high quality ingot can be achieved.