The direct cause of the collapse phenomenon is that the color plate is curled and unrolled (the Prepainted coils is off the line), and then the color plate is loosened. After the coil is loosened, because the number of steel strips per unit thickness of the steel coil is reduced compared to the normal state, the horizontal steel coil collapses under its own gravity. Uncoiling mainly refers to the relative slip between the rigid layers of the coiled steel strip, that is, there is not enough static friction between the rigid layers of the strip, that is to say, the large static friction between the strip steel layers is not enough to prevent the relative movement between the strip steel layers.
In practice, cold-rolled and hot-rolled coils often have coil collapse during coiling. The solution is usually to perform tension correction. The set value is generally adjusted to a certain tension on the basis of ordinary steel to cause friction between strips. Increased force. For different polyester Prepainted coils, the large static friction is related to the environmental temperature, humidity and the microscopic state of the friction surface of the material, especially the latter has a great relationship. After the coating is baked and cured, the inter-coating The contact method is surface-to-surface contact, and the coating will not be compressed and deformed. Appropriately increase the coiling tension and increase the static friction between the layers, which can effectively prevent the phenomenon of collapse.
