Sinking roller: a key component of continuous galvanizing production line

2025-09-05 11:44:39

In the continuous galvanizing production process of steel plates, the Sinking roller is the core equipment for achieving uniform galvanizing of steel plates. It guides the steel plate into the zinc solution, ensuring that the surface of the steel plate is in full contact with the zinc solution and forming a uniform galvanized layer. Its performance and condition directly affect the quality and production efficiency of galvanized steel plates, and it occupies an important position in the steel processing industry.

Structural composition and material properties

The sinking roller is mainly composed of a roller body, a shaft head, and a bearing assembly. The roller body is the part that comes into direct contact with the zinc liquid and steel plate, and is cylindrical in shape with a smooth and flat surface, ensuring that the steel plate is not scratched during transportation. The shaft head is located at both ends of the roller body, connected to the equipment frame through bearing components, supporting the roller body and ensuring its stable rotation.

Due to long-term operation in high-temperature zinc solution (temperature of about 450-500 ℃), the material of the sinking roller needs to have special properties. The commonly used materials are high nickel chromium alloys, such as 310S stainless steel or nickel based alloys. These materials have good resistance to zinc liquid corrosion and oxidation at high temperatures, which can reduce the erosion of zinc liquid on the roller body. At the same time, the material needs to have high temperature strength and wear resistance to prevent deformation or wear of the roller body under the friction of the steel plate and the flushing of the zinc liquid.

Part of the sunken roller surface will undergo special treatment, such as spraying ceramic coating or aluminum infiltration treatment, to further improve its corrosion resistance and wear resistance, and extend its service life. The interior of the roller body is usually designed with cooling channels, which reduce the temperature of the roller body by circulating cooling water to avoid material performance degradation caused by long-term high temperature.

Working principle and function

In the continuous galvanizing production line, the sinking roller is installed inside the zinc pot and completely immersed in the molten zinc liquid. When the steel plate enters the zinc pot, the running direction is first changed by the sinking roller, so that the steel plate is completely immersed in the zinc liquid. The surface of the steel plate is in full contact with the zinc liquid, and the zinc liquid forms a galvanized layer on the surface of the steel plate.

The rotation direction of the sinking roller is consistent with the running direction of the steel plate, and it is driven to rotate by the frictional force between the sinking roller and the steel plate, assisting in the smooth transportation of the steel plate in the zinc solution. The diameter and length of the roller body are designed according to the width and thickness of the steel plate to ensure uniform support of the steel plate, prevent bending or shaking of the steel plate in the zinc solution, and ensure the uniformity of the galvanized layer.

In addition, the sinking roller can also control the soaking time of the steel plate in the zinc solution. By adjusting the position and height of the sinking roller, the contact time between the steel plate and the zinc solution can be changed, thereby controlling the thickness of the galvanized layer. During the galvanizing process, a layer of zinc iron alloy will form on the surface of the submerged roller, which can reduce the direct corrosion of the roller body by the zinc solution and provide protection.

Application scenarios and usage precautions

Sinking rollers are mainly used in continuous hot-dip galvanizing production lines to produce galvanized steel sheets, galvanized steel strips, and other products, which are widely used in industries such as construction, automotive, and home appliances. In the field of construction, galvanized steel plates are used to make roofs, walls, etc., and have good corrosion resistance; In the automotive industry, galvanized steel plates are used for body manufacturing, which can improve the corrosion resistance of cars.

When using sinking rollers, attention should be paid to controlling the temperature and composition of the zinc liquid. Excessive temperature of the zinc solution will accelerate the corrosion and oxidation of the sinking roller, while low temperature will affect the quality of the galvanized layer; The content of aluminum, lead and other elements in the zinc liquid needs to be controlled within a reasonable range, otherwise it will affect the formation of the alloy layer on the surface of the sinking roller and shorten its service life.

Regularly check the operation status of the sinking roller, observe whether there are any abnormal vibrations, noise, or inflexible rotation, and promptly stop the machine for inspection if any problems are found. When replacing the sinking roller, it should be slowly removed from the zinc pot to avoid cracking of the roller body due to sudden temperature changes. When installing new rollers, ensure that the roller body is aligned with the centerline of the equipment to ensure smooth steel plate transportation.

Maintenance and extended lifespan

The maintenance of sinking rollers is crucial for extending their service life. Regularly clean the zinc slag and oxide scale on the surface of the sinking roller, as these impurities can affect the surface quality of the steel plate and the rotational accuracy of the sinking roller. Special tools should be used during cleaning to avoid scratching the surface of the roller body.

Regularly check the wear of the sinking roller, measure the changes in the diameter of the roller body, and replace the roller with a new one in a timely manner when the wear exceeds the specified value. For repairable sunken rollers, they can be repaired by welding wear-resistant alloys or other methods to restore their size and performance.

During non production periods, the sinking roller needs to be removed from the zinc pot for cleaning and rust prevention treatment, and stored in a dry and ventilated environment. At the same time, it is necessary to regularly lubricate the bearing components to ensure their flexible rotation and reduce friction and wear.

As a key component of a continuous galvanizing production line, the performance and condition of the sinking roller directly affect the quality and production efficiency of galvanized products. By selecting materials reasonably, using them correctly, and maintaining them carefully, the service life of sinking rollers can be effectively extended, production costs can be reduced, and stable production of galvanized steel sheets can be guaranteed.