Method to produce a metal strip, and production plant implementing said method

A method to produce metal strips, in particular steel, in a production plant configured to work in coil to coil and/or semi-endless rolling mode and/or in endless rolling mode, in which through a casting machine provided with a crystallizer is cast a slab, with a defined casting speed Vc, and said slab is hot rolled in a rolling station, comprising a number of rolling stands, to obtain metal strip having different strip thicknesses, wherein said casting machine, during casting, exerts a first action of liquid core reduction of the thickness of the slab exiting from the crystallizer, through a pre-rolling device with rollers, and a second action of solid core reduction of the thickness of the slab, through a drawing unit located downstream of said pre-rolling device, wherein said casting machine is selectively set, as said strip thicknesses vary, in order to exert a different action of reducing the thickness of the slab, in which said first action of liquid core reduction of the thickness is comprised between 5 and 25 mm, said second action of solid core reduction of the thickness is maximum 7 mm and is applied for strip thicknesses comprised between 0.6 mm and 3.5 mm, with an overall reduction thickness of the slab exiting from the casting machine comprised between 2% and 75%, and wherein the rolling mode of the slab is chosen in relation to said strip thicknesses and to the various types of produced steel, in order to optimize the productivity of the strip production plant with the lowest number of stands possible, while maintaining the maximum casting speed Vc in relation to the various types of produced steel.