Method and apparatus for continuous casting of a thin slab

A method of continuous production of a thin slab with reduced strain from a slab drawn from a continuous casting mold with a liquid core, the slab having a liquid phase plus a solid phase after being drawn from the mold, the method comprises the steps of:

• rolling the slab having a liquid core between a plurality of reduction roller blocks, each reduction roller block having a plurality of pairs of reduction rollers, thereby reducing the thickness of the slab with each pair of reduction rollers;
• rolling the slab having a liquid core with the plurality of pairs of reduction rollers at a location between a point directly below the mold from which the slab is continuously drawn, and a point of complete solidification of said slab;
• reducing the thickness of the slab having a liquid core with the plurality of pairs of reduction rollers such that the following relationship is satisfied:
• ##EQU5## and in addition
• P.sub.1,1(1) .gtoreq.P.sub.2,1(2) .gtoreq. - - - .gtoreq.P.sub.i,1(i),
• wherein "P" is the amount of reduction(mm)effected by each reduction roller pair, "j" is the number allotted to a pair of reduction rollers in a particular block, and "i" is the number of a particular reduction roller block, thereby controlling the amount of reduction in thickness such that the amount of reduction effected by each roller pair within the same block is substantially equal, and the amount of reduction effected by each upstream roller block is greater than or equal to the amount of reduction effected by each downstream roller block, or controlling the amount of reduction such that the amount of reduction effected by all of the roller blocks are all equal to each other;
• and
• the mean difference of reduction incline of adjacent roller blocks, expressed as (R.sub.(i-1) -R.sub.i), is reduced, wherein:
• ##EQU6## "R" being the reduction incline, "La" is the length of the roller block (mm), "P" is the amount of reduction (mm)effected by each reduction roller pair, "j" is the number allotted to a pair of reduction rollers in a particular block, and "i" is the number of a particular reduction roller block.

An apparatus for the continuous production of a thin slab from a slab drawn from a continuous casting mold with a liquid core, the slab having a liquid phase plus a solid phase after being drawn from the mold, the apparatus comprising:

• a curved segment;
• at least one reduction roller block provided in the curved segment for reducing the thickness of the slab having a liquid core;
• an upper roller segment frame for raising and lowering upper reduction rollers;
• a plurality of upper reduction rollers provided beneath the upper roller segment frame;
• a moving device for moving the upper roller segment frame up and down;
• a fixed upper frame of a gate shape for accommodating the moving device;
• upstream and downstream guide shafts which are fixed to the upper roller segment frame;
• an upper limit stopper for the upstream guide shaft, a lower limit stopper for the upstream guide shaft, a casting direction guide for the upstream guide shaft, each being fixed to the fixed upper frame;
• an upper limit stopper for the downstream guide shaft, a lower rotation limit stopper which controls the rotation of a downstream guide shaft, each being fixed to the fixed upper frame;
• a lower roller segment frame including a plurality of lower reduction rollers and provided beneath the fixed upper frame of the gate shape;
• and
• the upper roller segment frame is connected with the fixed upper frame so that the upper roller segment frame can move in the direction of a normal line that connects the center of the curved segment and the center of the upper roller segment frame simultaneously with movement of the upstream guide shaft and the casting direction guide, and the upper segment frame can rotate about the center of the upstream guide shaft between the upper limit stopper of the downstream guide shaft and the lower rotation limit stopper of the downstream guide shaft, thereby preventing misalignment.