Provided is a rolling straightening machine which enables outer-diameter-reducing rolling and straightening rolling of a pipe or tube material or a bar material at high speed with high accuracy. The rolling straightening machine includes at least two rollers arranged across a pass line of a pipe or tube material or a bar material, the at least two rollers having a gap therebetween, the gap being defined by an outer-diameter-reducing rolling portion having a diameter reduced from an upstream side toward a downstream side in the rolling straightening machine and a straightening rolling portion continuous from an exit side of the outer-diameter-reducing rolling portion toward a downstream side of the rolling straightening machine, the rollers having shapes which are symmetrical about the pass line in the outer-diameter-reducing rolling portion, and in the straightening rolling portion, asymmetrical to the pass line in the outer-diameter-reducing rolling portion.

Provided is a rolling straightening machine which enables outer-diameter-reducing rolling and straightening rolling of a pipe or tube material or a bar material at high speed with high accuracy. The rolling straightening machine includes at least two rollers arranged across a pass line of a pipe or tube material or a bar material, the at least two rollers having a gap therebetween, the gap being defined by an outer-diameter-reducing rolling portion having a diameter reduced from an upstream side toward a downstream side in the rolling straightening machine and a straightening rolling portion continuous from an exit side of the outer-diameter-reducing rolling portion toward a downstream side of the rolling straightening machine, the rollers having shapes which are symmetrical about the pass line in the outer-diameter-reducing rolling portion, and in the straightening rolling portion, asymmetrical to the pass line in the outer-diameter-reducing rolling portion.

The present application describes a Cold Rolling Mill (CRM) 200. The CRM 200 comprises a pair of working rolls 202 configured to apply stress on a metal strip for reducing thickness of the metal strip. The pair of working rolls 202 have a face width of 1350 mm. The CRM 200 further comprises a pair of intermediate rolls 204 configured to provide mechanical support to the pair of working rolls 202. The pair of intermediate rolls 204 have a face width of 1280 mm. The CRM 200 further comprises a pair of back-up rolls 206 configured to provide mechanical support to the pair of intermediate rolls 204. The back-up rolls 206 have a face width of 1300 mm. Bearing center distance of the CRM 200 is 2170 mm.

Mill rolls capable of rolling long kilometers used for ESP production line and a method for rolling long kilometers using the mill rolls. The mill rolls include rolls (3, 4), a bearing box (2) and a roll shifting hydraulic cylinder (1), wherein the middle portion of the surface of the roll sinks inwards, one end of the rolls is frustum-shaped, smaller and smaller outwards, so that the roll surface forms a compensation ramp, and the other end of the rolls is cylindrical. The upper roll (3) and the lower roll (4) have the same roll profile and are positioned in the opposite direction. The mill rolls are characterized by reduced runaway of the rolled product and a longer service life.

[Object] To suppress occurrence of shape defects in a material to be rolled and enable efficient and stable production of an H-shaped steel product with a flange width larger than a conventional flange width by creating deep splits on end surfaces of a material (e.g., slab) using projections with acute-angle tip shapes, and sequentially bending formed flange portions. [Solution] Provided is a method for producing H-shaped steel, the method including: a rough rolling step; an intermediate rolling step; and a finish rolling step. In a rolling mill that performs the rough rolling step, a plurality of calibers to shape a material to be rolled are engraved, the number of the plurality of calibers being four or more. Shaping of one or a plurality of passes is performed on the material to be rolled in the plurality of calibers. In a first caliber and a second caliber among the plurality of calibers, projections to create splits vertically with respect to a width direction of the material to be rolled are formed. In a second caliber and subsequent calibers among the plurality of calibers, reduction is performed in a state where end surfaces of the material to be rolled are in contact with caliber peripheral surfaces in shaping of at least one pass. In a third caliber and subsequent calibers among the plurality of calibers, a step of sequentially bending divided parts formed by the splits is performed.

Mill rolls capable of rolling long kilometers used for ESP production line and a method for rolling long kilometers using the mill rolls. The mill rolls include rolls (3, 4), a bearing box (2) and a roll shifting hydraulic cylinder (1), wherein the middle portion of the surface of the roll sinks inwards, one end of the rolls is frustum-shaped, smaller and smaller outwards, so that the roll surface forms a compensation ramp, and the other end of the rolls is cylindrical. The upper roll (3) and the lower roll (4) have the same roll profile and are positioned in the opposite direction. The mill rolls are characterized by reduced runaway of the rolled product and a longer service life.

[Object] To suppress occurrence of shape defects in a material to be rolled and enable efficient and stable production of an H-shaped steel product with a flange width larger than a conventional flange width by creating deep splits on end surfaces of a material (e.g., slab) using projections with acute-angle tip shapes, and sequentially bending formed flange portions.

[Solution] Provided is a method for producing H-shaped steel, the method including: a rough rolling step; an intermediate rolling step; and a finish rolling step. In a rolling mill that performs the rough rolling step, a plurality of calibers to shape a material to be rolled are engraved, the number of the plurality of calibers being four or more. Shaping of one or a plurality of passes is performed on the material to be rolled in the plurality of calibers. In a first caliber and a second caliber among the plurality of calibers, projections to create splits vertically with respect to a width direction of the material to be rolled are formed. In a second caliber and subsequent calibers among the plurality of calibers, reduction is performed in a state where end surfaces of the material to be rolled are in contact with caliber peripheral surfaces in shaping of at least one pass. In a third caliber and subsequent calibers among the plurality of calibers, a step of sequentially bending divided parts formed by the splits is performed.