Rolling stand for tubes or rounds

A rolling stand for tubes or rounds comprising two or more rolling rolls defining a rolling section of the rolling stand that is coaxial to a rolling axis of the rolling stand, each roll having

• a respective rolling surface defining a respective straight line of symmetry passing through the rolling axis and through a center of symmetry of the respective surface thus determining a first half and a second half of the respective surface,
• two gap zones having a radial distance of value H2 from the rolling axis, each gap zone being located at an adjacent roll,
• and a groove bottom zone having a radial distance of value H1 from the rolling axis at an intersecting point of the respective surface with the respective straight line of symmetry,
• wherein there are provided, for each roll on said respective rolling surface, at least three pushing zones, a first pushing zone of which is arranged on the respective straight line of symmetry at said groove bottom zone, a second pushing zone is circumferentially arranged in the first half of the respective surface between the respective groove bottom zone and the adjacent gap zone, at an angular distance of value αR from the respective straight line of symmetry, and a third pushing zone is circumferentially arranged in the second half of the respective surface between the respective groove bottom zone and the adjacent gap zone, at an angular distance of value αL from the respective straight line of symmetry,
• and wherein, at each of said at least three pushing zones, there is a respective point of relative minimum of a curve Rpass=H(α) representing the shape of the rolling surface along a plane orthogonal to the rolling axis, where H(α) is the radial distance of the rolling surface from the rolling axis in function of the angular distance a from the respective straight line of symmetry.