The disclosure provides a rolling mechanism for grain refinement of an M50NiL rod. The rolling mechanism includes two main rolls and two auxiliary rolls. The two main rolls are opposite to each other and the two auxiliary rolls are opposite to each other, and the two main rolls and the two auxiliary rolls are disposed around a rolling line to form a nip zone. In any cross section of the nip zone with the rolling line as a normal line, a first line connecting the central axes of the two main rolls is perpendicular to a second line connecting the central axes of the two auxiliary rolls; each main roll further includes a first protrusion portion, a first end portion and a second end portion. The first end portion and the second end portion are disposed opposite each other along a corresponding roll axis.

A cross-rolling unit and a method for setting the roll pass of a cross-rolling unit, having at least two rolls and a roll housing, in which at least one of the rolls is mounted such that its position can be adjusted in order to change the roll pass, allow the roll pass to be adjusted by means of a roll-positioning apparatus even during rolling, which roll-positioning apparatus is characterized by a housing-connected part and a roller-mill-connected part, which can be moved relative to the housing-connected part during rolling, which parts can be repositioned relative to each other, and/or which roll-positioning apparatus characterized by a drive which is dimensioned in such a way that rolling forces can be applied.

A cross-rolling unit and a method for setting the roll pass of a cross-rolling unit, having at least two rolls and a roll housing, in which at least one of the rolls is mounted such that its position can be adjusted in order to change the roll pass, allow the roll pass to be adjusted by means of a roll-positioning apparatus even during rolling, which roll-positioning apparatus is characterized by a housing-connected part and a roller-mill-connected part, which can be moved relative to the housing-connected part during rolling, which parts can be repositioned relative to each other, and/or which roll-positioning apparatus characterized by a drive which is dimensioned in such a way that rolling forces can be applied.