Case of electroplated diamond abrasive belt for polishing carbide coating roll

The roll is a tool that causes plastic deformation of the metal (rolled material). It is an important consumable component that determines the efficiency of the rolling mill and the quality of the rolled material. The roller is an important part of the rolling mill in the steel rolling mill. It uses the pressure generated by a pair or a group of rollers to roll steel. It mainly bears the effects of dynamic and static loads, wear and temperature changes during rolling.  Diamond has a Mohs hardness of 10, making it the hardest material ever discovered. Diamond abrasive belt is especially suitable for processing non-metallic and non-ferrous metal-based materials that are difficult to process with high hardness and brittleness.

Roll classification

There are many types of rolls. The commonly used roll types include cast steel rolls, cast iron rolls and forged rolls. There are also a small number of carbide rolls on the profile rolling mill.

Roller body shape

Rolls are classified in different ways. According to the shape of the roller body, it is divided into cylindrical and non-cylindrical rollers. The former is mainly used for the production of plates, strips, profiles and wires, while the latter is mainly used for the production of pipes. ​

According to whether they contact the rolling stock, they are divided into work rolls and back-up rolls. The roll that directly contacts the work roll is called a work roll; the roll that is placed on the back or side of the work roll in order to increase the stiffness and strength of the work roll and does not directly contact the work roll is called a backup roll.

According to the use of the machine frame, it is divided into preliminary roll, rough roll, intermediate roll and finishing roll.

According to the types of rolled materials, they are divided into plate and strip rolls, rail beam rolls, wire rod rolls and pipe rolls. It can also be divided into hot rolls and cold rolls according to the state of the rolled piece during rolling.

According to hardness value

(1) Soft roll: Shore hardness is about 30~40, used in billet opening machines, roughing mills of large section steel rolling mills, etc.

(2) Semi-hard roll: Shore hardness is about 40~60, used in roughing mills of large, medium and small section steel rolling mills and steel plate rolling mills.

(3) Hard-faced rolls: Shore hardness is about 60~85, used for roughing mills of thin plate, medium plate, medium section steel and small section steel rolling mills and support rolls of four-high rolling mills.

(4) Extra hard roll: Shore hardness is about 85~100, used in cold rolling mills.

At present, thermal spray technology is mainly used in the steel industry for wear resistance, anti-corrosion and spray welding of conveyor rollers. In steel enterprises, a large number of equipment workpieces operate under high temperature, high speed, heavy load or corrosive environment. Therefore, the quality and service life of these workpieces will directly affect the production efficiency, product quality and production cost of steel enterprises. Thermal spray technology is mainly used in special working conditions and workpieces with special surface requirements. Its typical applications include furnace rollers in various annealing furnaces, sinking rollers in hot-dip galvanizing lines, short-side copper plates in crystallizers, and a large number of cold and hot rolling processes. Roller. Thermal spray rollers account for more than 85% of all thermal spray parts.

Thermal spraying advantages:

1. Coating improves product quality

Surface defects of continuous annealing furnace rollers are reduced to almost zero after coating. It has a very significant effect on improving product quality.

2. Coating increases component life and reduces maintenance costs

Take the tension roll of the finishing mill as an example. The roll was originally hard-plated Cr and its life was 2.5 months. When the thermal spray coating is used, the service life is greatly extended, and the maintenance cost rate is reduced from 1.0 to 0.2~0.1.

3. Coating reduces production line downtime

Take the shearing line guide roller as an example. After the roller is strengthened by thermal spraying, the roller surface has no wear and the plate edges are smooth. The average parking time of the conventional guide roller is reduced to 30 minutes per month and is almost unnecessary, which greatly reduces the downtime and maintenance time.

Application of thermal spray technology in rollers:

1. continuous casting roll

The backup rollers, guide rollers, clamping rollers and other components in the continuous casting production line are often affected by factors such as various stresses and hot and cold fatigue, causing large cracks in the circumferential direction of the roller surface, resulting in roller damage and failure. After using self-fluxing alloy to strengthen the roller surface, the coating only produces tiny cracks with low crack propagation speed on its grain boundaries during use, which greatly extends the life of the continuous casting roller and prevents surface defects in the casting material. occurs and improves the quality of castings.

2. Cold rolled processing roll

The processing rollers in the cold rolling production line (such as tension rollers, guide rollers and straightening rollers, etc.) are required to have wear-resistant surfaces, small changes in surface roughness during use, and constant clamping force. The roller is usually surface-plated with chrome, but its wear resistance is not enough, which affects its service life. However, after the thermal spray coating is specially treated, the surface roughness changes slowly and the surface clamping force is not easy to decrease. The wear resistance of the specially treated coated roller is 5 to 10 times that of the chrome-plated roller.

3. Conductive roll

The conductive roller used for tin plating and galvanizing in electroplating production lines is made of conductive Fe-based and Cu-based materials and Hastelloy corrosion-resistant alloy, and its surface is plated with Ni or Cr. Due to the effects of corrosion, wear and attached foreign matter during the electroplating process, its lifespan is very short.

The electroplated conductive roller coating material should have the following properties:

(1) The conductivity can meet the requirements of the electroplating process;

(2) Corrosion and wear are difficult to cause changes in surface properties;

(3) The surface should be difficult to adhere or deposit foreign matter, and even if it adheres, it should be easy to remove.

Diamond has a Mohs hardness of 10, making it the hardest material ever discovered. Diamond abrasive belt is especially suitable for processing non-metallic and non-ferrous metal-based materials that are difficult to process with high hardness and brittleness.

The diamond abrasive belt made by electroplating process has high bonding strength between diamond and base cloth. In addition, it adopts a gapped grinding unit arrangement, which has better chip removal and lower grinding temperature. It can not only ensure the surface quality of the workpiece, but also ensure the surface quality of the workpiece. It can also ensure the intrinsic quality of the workpiece, thereby improving the fatigue strength of the parts, extending their service life and improving production efficiency. The grinding process of diamond abrasive belt also has the characteristics of less dust, less noise and low energy consumption, which is very energy-saving and environmentally friendly.

Recently, we had a customer inquire about polishing carbide coating, and moresuperhard provided him with several polishing options as follows:

—EDITOR: Doris Hu, Anna Wang

—POST: Doris Hu