Cooling extension device for secondary cooling area of small square billet continuous casting machine

The utility model relates to a cooling extension device for a secondary cooling area of a small square billet continuous casting machine, and belongs to the technical field of small square billet continuous casting machines in the metallurgical industry. According to the technical scheme, an outer arc water strip (5), a left side arc water strip (6), a right side arc water strip (7) and an inner arc water strip (8) are all distributed along an arc line, the common circle center point of the outer arc water strip, the left side arc water strip (6), the right side arc water strip (7) and the inner arc water strip (8) is O, four water nozzles (13) are arranged on each water strip at equal intervals, and the outer arc water strip (5), the left side arc water strip (6), the right side arc water strip (7), the inner arc water strip (8) and the four water nozzles (13) on each water strip at equal intervals form a cooling section casting blank spraying system; the arc radius of the center line of the outer arc water