Method for continuous casting of a metal product, to obtain a productivity between 50 ton/h and 150 ton/h, comprising: - supplying a crystallizer having a casting cavity, into which the liquid metal is cast, defined by walls connected to each other in correspondence with edges, wherein the upper level of the liquid metal defines a meniscus, wherein said cavity has an octagonal-shaped cross-section with a distance between two opposite walls comprised between 110 mm and 220 mm, and length "LM" comprised between 500 mm and 1500 mm, and it has a taper converging downward of the single type comprised between 0.8 %/m and 1.5 %/m or of the multiple or parabolic type comprised between 2 %/m and 4 %/m in the meniscus zone, and between 0.2 %/m and 1.0%/m in the lower part of the crystallizer, wherein the distance between the cooling fluid and the internal walls of the crystallizer in direct contact with the liquid metal, measured in a direction orthogonal to the axis of the crystallizer, has a value comprised between 8 mm and 10 mm; - providing foot rolls at the exit of the crystallizer; - providing guide rolls directly downstream of the foot rolls in order to define a machine radius Rm comprised between 5 m and 25 m, preferably between 7 m and 20 m, more preferably between 10 m and 15 m, and even more preferably between 9 m and 12 m; - providing a primary cooling in the crystallizer with a thermal flow value in correspondence with the meniscus greater than 6MW/m 2 and up to 14MW/m 2 and with an average value comprised between 3MW/m 2 and 5.5MW/m 2; - casting at a casting speed between 6m/min and 15m/min, wherein the pressure of the cooling fluid in the segment corresponding to the upper zone of the crystallizer, which corresponds to the vicinity of the meniscus, is comprised between 6 and 20 bar, while in the lower zone of the crystallizer, which substantially corresponds to the end part of the crystallizer, it is comprised between 2 and 10 bar. - supplying a crystallizer having a casting cavity, into which the liquid metal is cast, defined by walls connected to each other in correspondence with edges, wherein the upper level of the liquid metal defines a meniscus, wherein said cavity has an octagonal-shaped cross-section with a distance between two opposite walls comprised between 110 mm and 220 mm, and length "LM" comprised between 500 mm and 1500 mm, and it has a taper converging downward of the single type comprised between 0.8 %/m and 1.5 %/m or of the multiple or parabolic type comprised between 2 %/m and 4 %/m in the meniscus zone, and between 0.2 %/m and 1.0%/m in the lower part of the crystallizer, wherein the distance between the cooling fluid and the internal walls of the crystallizer in direct contact with the liquid metal, measured in a direction orthogonal to the axis of the crystallizer, has a value comprised between 8 mm and 10 mm; - providing foot rolls at the exit of the crystallizer; - providing guide rolls directly downstream of the foot rolls in order to define a machine radius Rm comprised between 5 m and 25 m, preferably between 7 m and 20 m, more preferably between 10 m and 15 m, and even more preferably between 9 m and 12 m; - providing a primary cooling in the crystallizer with a thermal flow value in correspondence with the meniscus greater than 6MW/m 2 and up to 14MW/m 2 and with an average value comprised between 3MW/m 2 and 5.5MW/m 2; - casting at a casting speed between 6m/min and 15m/min,