During the production of submergence rollers, minor defects such as scratches on the rollers may occur. How do these phenomena occur? What are the influencing factors?
In fact, there are numerous influencing factors, such as in terms of equipment, generally there are several reasons:
The mechanical structure of the submerged roller assembly should prioritize the groove type on the roller surface from the perspective of increasing friction. There are two reasons for this. Firstly, zinc is a heavy metal with poor fluidity and high viscosity. During the high-speed movement of steel strips and submerged rollers, a zinc liquid film easily forms between them, serving as a certain lubricating effect and reducing the transmission friction between the steel strip and the submerged roller, which is prone to cause indentation defects on the submerged roller. Therefore, the grooves must facilitate the flow of zinc liquid between the steel strip and the submerged roller, preventing the formation of sliding films. Secondly, when designing the grooves on the roller surface, it should be approached from a mechanical standpoint to ensure the submerged roller and the steel strip are in the optimal state of stress, aiming to maximize the transmission friction between them. Thus, both points must be considered when designing the grooves on the submerged roller roller surface.
b. The material requirements for the roller surface are also a factor. Due to the special working position of the submerged roller, the material of the roller surface should meet three requirements: 1. Corrosion resistance, 2. Hardness requirements, 3. Roughness requirements.
c. The influence of the self-weight of the submerged roller, from a dynamical perspective, another significant factor affecting the transmission of the submerged roller is its own weight. Under normal production conditions, the submerged roller is subjected to the positive pressure of the strip steel, the frictional force between the strip steel and the submerged roller, the force acting between the bearing seat, and its own weight. By the synthesis and decomposition of forces, the resultant force of the above four forces can be decomposed into radial normal pressure and radial tangential force, of which the radial tangential force is the driving force for the rotation of the submerged roller; its magnitude directly affects the rotational condition of the submerged roller.
d. The structural design requirements for the submerged roller assembly must address the axial fixation issue to prevent the submerged roller from sliding axially during rotation. Especially for steel strips with poor shape, such as trapezoidal or uneven thickness, the uneven force distribution between the steel strip and the submerged roller during contact transmission can easily cause the steel strip to deviate, leading to axial sliding on the submerged roller and resulting in the scratching defect of the submerged roller. The clearance between the bearing and the bearing seat of the submerged roller should be as small as possible; excessive clearance can easily cause radial跳动 in the submerged roller.