Rolling mill stand and method of changing a work roll assembly thereof

A rolling mill stand for rolling a metallic product, comprising:

• first and second supports spaced apart from each other in an X dimension and each defining a window that extends in a Y dimension which is perpendicular with the X dimension, each window comprising opposing upper channel formations and opposing lower channel formations;
• upper fixed rails, each extending in the X dimension between a respective one of the opposing upper channel formations of the first support and a respective one of the opposing upper channel formations of the second support;
• lower fixed rails, each extending in the X dimension between a respective one of the opposing lower channel formations of the first support and a respective one of the opposing lower channel formations of the second support;
• a work roll assembly comprising an upper work roll and a lower work roll each having a longitudinal axis extending in the X dimension, the upper work roll and the lower work roll being arranged to be spaced apart so as to form a gap for receiving the metallic product for rolling in the Y dimension, two ends of the upper work roll being received by respective upper work roll chocks and two ends of the lower work roll being received by respective lower work roll chocks, each of the upper work roll chocks and the lower work roll chocks comprising bending wings which extend in the Y dimension, each of the bending wings comprising at least one transportation element, each of the bending wings of the upper work roll chock being slidingly received in a respective one of the opposing upper channel formations and each of the bending wings of the lower work roll chock being slidingly received in a respective one of the opposing lower channel formations;
• and
• work roll bending cylinders each located in one of the opposing upper channel formations or opposing lower channel formations and configured to engage a respective one of the bending wings, each of the work roll bending cylinders being arranged to be selectively extendable and retractable in a Z dimension which is perpendicular with each of the X and Y dimensions in order to raise and lower a respective one of the upper work roll and the lower work roll,
• wherein with respect to each said window there is provided first and second movable rails located at each of the opposing upper channel formations or at each of the opposing lower channel formations, each of the first and second movable rails being independently movable in the Y dimension between an idle position which is out of alignment with a respective one of the upper or lower fixed rails in the X dimension and a service position which is in alignment therewith in the X dimension,
• and wherein:
• when the first and second movable rails are in the idle positions movement of the bending wings in the Z dimension is unimpeded by the first and second movable rails;
• and
• when the first and second movable rails are in the service positions the first and second movable rails together with the respective fixed rail form a continuous rail for guiding respective said transportation elements of the bending wings in the X dimension in order to selectively withdraw the work roll assembly from the rolling mill stand and insert the work roll assembly in the rolling mill stand.