Mould for the continuous casting of a metal material

Mould for the continuous casting of a metal material, having a crystallizer comprising a plurality of plates which define between them a casting channel having a casting direction in which said metal material is able to pass according to said casting direction, and wherein at least one of said plates has an internal surface that delimits said casting channel and an external surface opposite said internal surface and on which there is a plurality of grooves that develop longitudinally in a manner substantially parallel to said casting direction and have an overall length, wherein on said external surface of each of said plurality of plates there is hermetically attached at least one counter-plate to define, by means of said one or more grooves, one or more cooling channels, wherein said plurality of grooves comprises at least one functional groove having a width, measured in a direction substantially parallel to said external surface and substantially orthogonal with respect to said casting direction, which is not constant along said overall length, wherein said at least one functional groove comprises a first segment having a first length and a first width, and at least one second segment communicating fluidically with said first segment and having a second length and a second width, said second width being smaller than said first width and the sum of said first length and of said second length defining said overall length.