Abstract: A method for continuous casting of steel comprises charging molten steel from a tundish into a mold through exit ports of an immersion nozzle, introducing a magnetic field vertically to a flow of the molten steel from the exit ports by the use of at least a pair of direct current magnets which are arranged on the outer side of copper plates on the wide side of the mold, the immersion nozzle being placed between the direct current magnets and polarities of magnetisms on the top side of the magnets being the same, and casting the molten steel at a predetermined casting rate. One magnetic pole of the direct current magnet is positioned at an upper end of copper plate on the wide side of the mold and the other magnetic pole being positioned at lower than the exit port of the immersion nozzle and on the outer side of copper plate on the wide side of the mold. The immersion nozzle has two exit ports, each of which has an angle of 15.degree. to 45.degree. downward.

Abstract: A spray nozzle which has a nozzle main body and opening at one end in fluid communication with an inflow hole passing into the central portion of the nozzle main body. The inflow hole has a rounded orifice portion in fluid communication with an elongated discharge slot at an opposite end of the nozzle main body. Stirring channels extend along and are in fluid communication with the inflow hole. Each stirring channel has a cup-shaped end which is laterally adjacent the rounded orifice portion of the inflow hole. The cut-shaped portion of the stirring holes causes a reverse flow of mixed gas and liquid which passes down the stirring channels such that mixed gas and liquid passing through the inflow hole towards the elongated discharge slot is agitated and a uniform spray with fine droplets is jetted from the discharge slot.

Abstract: In continuously casting molten steel at least a pair of rolls is disposed near the leading end of the crater at which solidification of the molten steel in the cast piece completes so as to roll the cast piece at a reduction rate of from 0.1 to 2.0%. The variation in the thickness of the cast piece is detected and compared with a definite reference value for controlling the drawing speed and or the quantity of the secondary cooling water.

Abstract: In continuously casting steel, at least two pairs of reduction rolls are arranged near the crater top where the solidification of the molten steel in the cast strand is completed, said reduction rolls having a roll pitch of 200 to 420mm and giving a draft per pair of 0.1 to 2.0%, and said cast strand is reduced near the to of said crater, whereby the inner quality of said cast strand is remarkably improved.