The horizontal rolling mill is mainly used for the production of various section steel, narrow hot strips and small billets. The following is the main features of the horizontal rolling mill :
(1) A row of rolling mills is driven by a motor. The rolling speed of each rolling mill is the same, and the rolling speed cannot be increased as the length of the rolling stock increases, so the output is low and the labor productivity is low;
(2) The structure of the rolling mill is generally three-roller or two-roller alternate;
(3) The rolling mill operation mode is mostly shuttle rolling or loop rolling. With flexible deformation and strong adaptability，each rolling mill can roll several times. The product range is wide and the operation is relatively easy;
(4) The rolling mill equipment is simple, with less investment and quick construction.
The tandem rolling mills are arranged in a row according to the rolling direction of the rolling stock. The rolling stock is only rolled once on each rolling mill. Each rolling mill is driven separately. Each rolling mill has different rolling speeds, that is, the rolling speed of the rolling rolls can be related to the rolling stock. The reduction in the section or the increase in the length of the rolled piece increases. Therefore, compared with the horizontal rolling mill, the rolling mill has the advantages of short gap time, high production efficiency, and less auxiliary equipment.
However, when this kind of rolling mill works, the rolling stock sequentially enters each rolling mill without forming a continuous rolling relationship, and the rolling stock is lengthened as the number of rolling passes increases, and the distance between the racks increases as the length of the rolling stock increases, so Longitudinal mills occupy a longer plant. This type of rolling mill is only suitable for large and medium-sized steel production. In order to overcome this shortcoming, the tandem mill was further developed into an off-road and a chess mill.
On cross-country rolling mills and staggered rolling mills, the head and tail of the rolling stock are alternated in different passes, which means the upper head becomes the tail of this track, and the tail of this track becomes the next head again. The rolling stock has lateral movement during the rolling process. The arrangement of the cross-country rolling mills and staggered rolling mills are more concentrated, which overcomes the shortcomings of the long mill. These mills also have a fast rolling speed and are suitable for the production of large, medium and small complex sections of steel such as I-beam, channel steel and H-beam.