The roll is a production tool that plastically deforms the metal. It is subject to complex stress states during production, and the roll is prone to failure, spalling, fracture, and roll surface damage. Among the failure modes of rolls, there are many types of roll surface damage, and it is also a common failure mode, including roll surface cracks, indentations, oxide film peeling, slag inclusion, steel sticking, abnormal wear and so on.

1. Cracks on the roll surface

Cracks are divided into normal cracks and abnormal cracks. Normal cracks are also called thermal cracks. The roll surface is gradually broken due to thermal stress generated by multiple temperature cycles. It is a micro-surface layer phenomenon that occurs on the roll surface. Normal cracks are thermal shock cracks caused by accidents such as slipping, sticking, sticking, stacking, tail flicking, etc. during the rolling process, and locally formed cracks with a certain depth and ductility on the surface of the roll surface.

2. Indentation

Mainly refers to the intrusion of foreign objects such as iron oxide scales due to cleaning reasons during the production process, resulting in continuous or discontinuous distribution of irregular-shaped pits on the roll surface.

3. The oxide film falls off

At the beginning of rolling, after a period of hot roll, a thin oxide film of silver-gray or light blue is formed on the surface of the roll, which is very important to protect the roll surface and improve the surface quality of the rolled piece. Due to the repeated action of the rolling force , causing the oxide film to produce micro-cracks around the carbide; when the cooling capacity of the roll is insufficient, it is difficult to form a dense oxide film on the roll surface, and even if the oxide film is formed, it will deteriorate quickly. If the rolling is unreasonable, the oxide film is quickly destroyed during the formation process, which will cause the oxide film to fall off, leaving meteor spots and other defects on the roll surface, resulting in increased roll surface roughness and increased wear.

4. Steel sticking, abnormal wear, etc.

Due to abnormal rolling, the roll surface and the rolling piece are stuck together, and steel sticking occurs; the unreasonable process parameters during rolling cause excessive consumption of rolls with the same width and kilometers, resulting in uneven wear of the roll surface.

In production, we should start from standardized operation and equipment maintenance to avoid the occurrence of roller surface damage in the above aspects.