Plate rolling process is a metal forming process that involves passing flat metal sheets through a series of rollers to achieve a desired curvature or cylindrical shape. This process is commonly performed using plate rolling machines, which come in various configurations, including three-roll machines and four-roll machines.
The plate rolling process is a process of continuous three-point bending of the plate material using a plate rolling machine. At the beginning of rolling, the plate material is placed between the upper and lower working rollers. The upper roller rises and falls vertically, and the two lower rollers rotate and move horizontally relative to the axis of the upper roller. When the upper roller descends, the plate undergoes plastic deformation and bends between the upper and lower working rollers. The lower roller rotates continuously to drive the steel plate forward and backward through the friction between the plate and the roller to complete the rolling.
The rolling process of the plate rolling machine is divided into 4 steps
Pre-bending. When rolling, there is a length at both ends of the plate that does not bend because it cannot contact the upper roller, which is called the remaining straight edge. In terms of technology, the minimum force arm for the plate to start bending is called the theoretical remaining straight edge, and its size is related to the equipment structure and its bending form (symmetrical bending, asymmetrical bending).
Centering. The purpose of centering is to make the workpiece generatrix parallel to the roller axis to prevent twisting.
In order to prevent the steel plate from twisting and tilting during the rolling process, and to prevent the steel plate from borrowing in the axial direction, the process of straightening the steel plate on the plate rolling machine before rolling is called centering.
- Common centering methods for three-roller plate rolling machines: ① Centering baffle centering method; ② Inclined feeding centering method; ③ Roller groove line centering method.
- Common centering methods for four-roller plate rolling machines: Side roller centering method. The rolling (i.e. rolling and bending) of steel plates is a process method for bending plates that have been cut and cut according to size requirements and have been processed on the edges.
Rolling. Rolling is the main process of product forming, which is divided into one-time feeding and multiple feeding. Multiple feeding is often used for rolling thick plates. The number of feedings depends on the process restrictions (such as the maximum allowable deformation must not be exceeded during cold rolling) and equipment restrictions (such as non-slip conditions and power conditions). When the springback of cold rolling is significant, a certain amount of overwinding must be added.
Rounding. The purpose of rounding is to make the curvature of the whole circle as uniform as possible to ensure product quality. Generally, the rounding process is divided into three steps:
- Loading: Adjust the working roller to the required maximum correction curvature according to experience or calculation.
- Rolling: Roll the roller 1 to 2 turns at the correction curvature to make the curvature of the whole roll uniform.
- Unloading: Gradually unload the load so that the workpiece is rolled multiple times under the gradually reduced correction load.
Conclusion
The plate rolling machine has good comprehensive mechanical properties, high precision, high strength, strong wear resistance, easy operation, and is suitable for high-load work.