Crystallizer for the continuous casting of a metal product, and corresponding casting method

A method for continuous casting of a metal product, to obtain a productivity between 50 ton/h and 150 ton/h, the method including the following steps:

• supplying a continuous casting apparatus, the continuous casting apparatus comprising a mold and a crystallizer for endless, semi-endless, or billet-to-billet continuous casting of a metal product, the crystallizer having a casting cavity into which a liquid metal is cast, and the casting cavity defined by walls connected to each other in correspondence with edges, wherein an upper level of the liquid metal defines a meniscus, wherein said metal product is a billet and comprises an octagonal-shaped billet, and wherein said casting cavity has an octagonal-shaped cross-section with a distance between two opposite walls comprised between 110 mm and 220 mm and a length between 500 mm and 1500 mm;
• providing primary cooling means to achieve a heat exchange between the walls of the crystallizer and a skin of the metal product, with a thermal flow value in correspondence with the meniscus comprised between 6 MW/m2 and 14 MW/m2 and with an average value comprised between 3 MW/m2 and 5.5 MW/m2;
• providing a plurality of cooling members downstream of the mold to perform a secondary cooling of the cast product, wherein said cooling members comprise a plurality of delivery nozzles that deliver a liquid with a pressure at exit from said nozzles is comprised between 0.5 bar and 12 bar, and wherein specific water flow rates are between 1.2 L/kg of cast steel and 2.5 L/kg of cast steel;
• and
• casting at a casting speed between 6 m/min and 15 m/min.