Straight arc casting machine alloy steel sheet billet continuous casting foot roller segment narrow surface cooling method

The present invention discloses a straight-curved type casting machine low-alloy steel slab continuous casting full-rolling section narrow face cooling method, and is aimed at solving the problem of that on the casting blank surface corner portion of low-alloy steel the transverse crack can be easily produced. Said invention belongs to the field of metal continuous casting blank cooling and surface quality control technology. Said method is characterized by that in the full-rolling section of continuous casting straight-curved type casting machine slab said invention utilizes the nozzles which are symmetrically mounted at left side and right side of casting blank pouring direction to cool the narrow face of said casting blank, and adopts rectangular nozzles to symmetrically and simultaneously cool the narrow faces of left and right two sides of casting blank. Said invention also discloses a kind of rectangular nozzle for said method, the water outlet hole of its sprayer is a hole with rectangular section. Said invention can reduce casting blank cooling strength of full-rolling section under the crystallizer and can improve casting blank cooling uniformity, so that it can eliminate casting blank surface corner portion transverse crack defect of continuously-cast high-strength low-alloy steel whose steel quality is P510L, P590L, J55 and X52, etc.