What is a rolling mill? What are the characteristics and classification of a rolling mill? The reason why it is called a rolling mill is because it is suitable for rolling many varieties of steel. The rolling mill is mainly used for rolling various types of steel, such as: rail, I-beam, channel steel, steel sheet pile, unequal angle steel and other types of steel. Next to introduce the characteristics and classification of the mill. Details are as follows:

Characteristics of 1. rolling mill
1. The complex cross-section pass pattern composed of four rollers can compress each component on the cross-section at the same time, the deformation of the rolled piece is uniform, the speed difference around the cross-section is small, and the internal stress of the rolled piece is small.
2, you can use a smaller diameter roll (because there is no need to slot on the roll), rolling products with higher legs and wider waist, and can make the inner side of the legs without slope. This is difficult to achieve in the ordinary two roll mill.
3. The reduction of the legs and waist of the rolled piece can be adjusted separately, which simplifies the adjustment of the rolling mill during rolling.
4. High rolling precision, less roll wear and reduced energy consumption.

Classification of 2. rolling mills
The form of rolling mill is divided into four types according to the structure, namely, closed type, UD prestressed type, SC connecting plate type and short stress line type rolling mill.

The common closed rack is composed of closed archways, upper and lower horizontal rollers, bearing seats and stands of vertical roller box. When changing rolls, the horizontal and vertical rolls and their bearing seats can only enter and exit from the side of the memorial arch window. Due to the large diameter of the horizontal roller of the rolling mill, the volume of the vertical roller shaft seat is also large, and the width of the memorial arch window must be greater than the above two, so the upper beam of the frame is wider, the column is higher, the equipment is heavy, and the rigidity of the frame is also poor.

UD prestressed/short stress rack consists of three parts: lower rack with lower horizontal roller and bearing seat, upper rack with upper horizontal roller and bearing seat, and middle part with vertical roller. These three parts of the rack are respectively connected by four hydraulic prestressed tie rods, which can be swung out to the outside, and the prestressed force can reach more than twice the large rolling force. The UD rack roll is lifted from the top. The size of the rack window is only related to the size of the roll neck and bearing seat. Therefore, the width of the window can be reduced by 40%, the height of the column can be reduced by 20%, and the bending of the beam under the rolling pressure is reduced by 1/3. Under the condition that the cross-sectional dimensions of the column and the beam are the same, the rigidity of the UD rack is about 3 times that of the closed rack.

The two archways of the SC frame are not on both sides of the horizontal roller, but are arranged in front of and behind the roller. The archways are connected with the upper and lower beams by connecting plates. During rolling, the rack arch becomes a steel plate in a plane stress state under the action of rolling force, so that the strength and rigidity of the entire rack are improved. The top and sides of the rack are open, and the roll change is convenient. This kind of frame adopts eccentric structure to adjust the opening degree of horizontal roller and vertical roller, and the adjustment range is small, which is suitable for continuous rolling unit.

The short-stress linear rolling mill does not have a common memorial arch. The component bearing the rolling load is a high-rigidity closed frame. The vertical pressure of the horizontal roller is composed of two upper beams and two lower beams connected together by tie rods. Four pressing screws are connected with the tie rods into one body. The upper and lower beams can be adjusted symmetrically to the rolling line. Compared with the closed frame, the rigidity is good, the weight of the equipment is only 2/3 of that of a normal closed rack. At present, most small and medium-sized production lines at home and abroad use this type of model.

UD prestressed frame and SC connecting plate frame, the main characteristics of the rolling mill are: when changing rolls, the yoke frame is opened, the vertical roll is removed from the frame opening, and the open yoke structure is adopted, which can increase the thickness of the frame to improve the rigidity of the rolling mill and improve the defect of poor rigidity of the closed frame.