In the production of sunken rollers, some small defects sometimes occur, such as sunken roller scratches, etc., how did this phenomenon happen? What are the influencing factors?

In fact, there are many influencing factors. For example, in terms of equipment, there are generally the following reasons:

a. The mechanical structure of the sunk roller device is considered from the perspective of increasing friction. The groove type of the sunk roller surface should be considered first. The reason is two points. The first point is that zinc is a heavy metal, and its zinc liquid has poor fluidity and high viscosity. It is easy to form between the steel strip and the sinking roller during the high-speed movement of the steel strip and the sinking roller A layer of zinc liquid film has a certain lubricating effect, reducing the transmission friction between the steel strip and the sinking roller, which is easy to cause the sinking roller scratching defect. Therefore, the groove must be conducive to the flow of the zinc liquid between the strip steel and the sinking roller to prevent the formation of a sliding film of the zinc liquid. The second point is that when designing the groove of the sunken roller surface, from the mechanical point of view, the sunken roller and the steel strip are in the best stress state, and the transmission friction between the two is increased as much as possible. Therefore, when designing the groove of the sunken roller surface, the above two points must be considered.

b. The requirement of roller surface material is also one of the influencing factors. Due to the special working position of the sunken roller, the material of the sunken roller surface should meet three requirements: 1. corrosion resistance, 2. hardness requirements, 3. roughness requirements.

 c. The influence of the self-weight of the sunken roller. From a dynamic point of view, another important factor affecting the transmission of the sunken roller is the self-weight of the sunken roller. Under normal production conditions, the sinking roller is subjected to the positive pressure of the strip steel, the frictional force between the strip steel and the sinking roller, the force between the bearing housing and the self-weight. It can be seen from the synthesis and decomposition of the force that the combined force of the above four forces can be decomposed into radial positive pressure and radial tangential force, of which the radial tangential force is the driving force for the rotation of the sinking roller, and its magnitude directly affects the rotation of the sinking roller Happening.

d. The structural design requirements of the sunk roller device, the sunk roller device must be designed to solve the problem of axial fixation, to prevent the sunken roller from slipping axially during rotation; especially for some strips that are not good in shape, such as wedge, Uneven thickness of the steel strip, when they are in contact with the steel strip for transmission, the stress between the steel strip and the sunken roller is uneven, which is easy to cause the steel strip to deviate, causing the steel strip to slide axially on the sunken roller and cause sinking. Scratch defects of the roller. The gap between the bearing of the sinking roller and the bearing seat should be as small as possible; too large a gap is likely to cause the radial runout of the sinking roller.