Industrial tungsten carbide coated rollers play an indispensable role in modern manufacturing and processing industries. The thickness and quality of the coating directly affect the service life, wear resistance and working performance of the roller. Tungsten carbide coating is currently the most widely used surface treatment technology on industrial rollers. Due to its excellent wear resistance, corrosion resistance and high hardness, it is widely used in heavy industry, chemical industry, printing industry, metallurgy industry and other fields.

This article will explore the thickness of tungsten carbide coating, factors affecting thickness, how to choose the appropriate coating thickness and the impact of thickness on industrial roller performance to help better understand the working principle and importance of industrial tungsten carbide coating rollers.

What is tungsten carbide coating?

Tungsten carbide coating is a hard alloy coating whose main components are compounds of tungsten and carbon. Tungsten carbide has a chemical formula of WC and has extremely high hardness, almost comparable to diamond, and also has excellent wear resistance and corrosion resistance. Coating the surface of industrial rollers with tungsten carbide can greatly improve the surface hardness of the roller, thereby extending its service life and improving its corrosion resistance.

Tungsten carbide coatings are usually applied through a thermal spraying process. In this process, tungsten carbide powder is melted at high temperature and sprayed onto the surface of the roller at a very high speed. The coating gradually accumulates to form a uniform and dense protective layer, providing excellent surface protection for the roller.

What is the standard thickness range of tungsten carbide coatings?

The thickness of tungsten carbide coatings is usually between 50 microns (0.05 mm) and 500 microns (0.5 mm), depending on the application scenario, working environment and use requirements of the roller. The choice of coating thickness must balance the wear resistance, impact resistance and other working characteristics of the roller.

● Thin coating (50~150 microns): Thin coatings are mainly used for light or medium-loaded industrial rollers. These rollers usually work in a low-friction, low-impact environment, so they do not require a too thick protective layer. The advantage of thin coating is that it is low cost and can maintain a high surface finish, which is suitable for some fine processing fields, such as printing rollers, coating rollers, etc.

● Medium coating (150~300 microns): Medium-thick tungsten carbide coatings are often used in applications that require a balance between wear resistance and corrosion resistance. This type of coating is widely used in steel rolling rollers in the metallurgical industry, calendering rollers in the papermaking industry, etc. These rollers need to work in a high-wear environment, and the medium thickness of the coating can provide sufficient protection without affecting the working accuracy of the roller.

● Thick coating (300~500 microns): Thick coatings are generally used for industrial rollers in heavy loads and extreme environments. For example, rollers in mining machinery or rollers used to handle corrosive chemicals. This type of coating has extremely high wear resistance and impact resistance, which can greatly extend the service life of the roller, but it will also increase the manufacturing cost.

What are the selection criteria for the thickness of tungsten carbide coatings?

Working conditions and degree of wear

The working conditions of the roller are the primary factor in determining the thickness of the coating. If the roller is subject to high friction or frequent contact with rough, hard materials, a thicker tungsten carbide coating can better delay wear and extend service life. In some high-load, high-wear applications, a tungsten carbide coating with a thickness of nearly 500 microns is a more ideal choice.

Surface finish requirements

There is a direct relationship between the thickness of the coating and the surface finish. In some industries that require extremely high surface smoothness, such as printing and coating industries, the surface finish of the roller must be maintained to a certain standard. Such rollers usually use a thinner tungsten carbide coating to ensure surface flatness and smoothness without the rough and uneven surface caused by thick coatings.

Corrosive environment

If the industrial roller is in a highly corrosive environment (such as chemical plants, paper mills, etc.), the tungsten carbide coating needs to provide not only wear protection, but also corrosion resistance. Thicker coatings can provide stronger corrosion protection for the roller to avoid premature failure due to corrosion.

Operating temperature

When industrial rollers work at high temperatures, the thermal expansion coefficient of the material will affect the adhesion of the coating. Thinner coatings provide better adhesion and stability at high temperatures, while thicker coatings may peel or crack under extreme heat conditions. Therefore, industrial rollers used in high temperature environments usually require a medium-thickness tungsten carbide coating to ensure long-lasting performance.

How does coating thickness affect roller performance?

The difference in coating thickness not only affects the wear resistance and service life of the roller, but also its overall performance. The following are the main effects of tungsten carbide coating thickness on industrial roller performance:

Wear resistance

Tungsten carbide has an extremely high hardness, and the wear resistance of the roller increases significantly with increasing coating thickness. In high-friction and high-wear applications, thick coatings can effectively reduce the wear rate of the roller and reduce the frequency of replacement and maintenance. However, in some applications with strict surface finish requirements, too thick coatings may cause unnecessary surface roughness, so a balance needs to be found between wear resistance and finish.

Impact resistance

Although tungsten carbide has high hardness, it is relatively brittle. In an environment with strong impact, too thick coatings may crack or fall off. Therefore, in situations where strong impact resistance is required, extremely thick coatings are usually not selected, but the coating thickness is adjusted to enhance its impact resistance.

Surface finish

The thickness of the coating directly affects the surface finish of the roller. Thin coatings are usually smoother and suitable for industrial applications that require high surface quality, while thicker coatings may produce minor unevenness during the coating application process, which in turn affects the surface finish. Therefore, for application scenarios with high surface finish requirements, thinner coatings are usually selected.

Corrosion resistance

Tungsten carbide coatings not only have excellent wear resistance, but also excellent corrosion resistance. The thicker the coating, the better it prevents chemicals from penetrating into the roller substrate, thereby extending the service life of the roller. Especially in industrial environments with corrosive gases or liquids such as chemicals and pharmaceuticals, thicker tungsten carbide coatings are ideal for corrosion protection.

How to detect the thickness of tungsten carbide coatings?

The thickness of tungsten carbide coatings needs to be strictly tested and controlled during production and use to ensure that it meets the requirements of specific applications. Common detection methods include the following:

Magnetic induction thickness measurement

Magnetic induction thickness measurement is a common non-contact thickness detection method, which is mainly suitable for the thickness detection of coatings on magnetic substrates. By measuring the change in magnetic resistance between the coating and the substrate, the thickness of the coating can be quickly and accurately obtained.

Ultrasonic thickness measurement

Ultrasonic thickness measurement is a non-destructive measurement method suitable for thickness detection of different substrates and coatings. By emitting ultrasonic waves, the probe can accurately calculate the thickness of the coating after receiving the reflected wave. This method is widely used to measure the coating thickness of industrial rollers, especially when the coating is thick, this method shows extremely high measurement accuracy.

Microscopy

Microscopy is a destructive test method that observes the thickness of the coating under a microscope after cutting the coating sample. This method is very accurate, but due to its destructive nature, it is usually only used in laboratory testing or quality control.

Jiangsu Jinhang Machinery Manufacturing Co., Ltd. (JH Machinery) is a renowned manufacturer of industrial rolls in China, offering customized roll solutions for global buyers. Established in 2001, we provide a wide variety of rolls, including tungsten carbide rolls, cooling rolls, and ceramic anilox rolls. Our ISO9001-certified factory boasts advanced equipment, ensuring every product meets high precision standards. We support industries such as mining, printing, and packaging with affordable wholesale prices and excellent customer service. Choose JH Machinery for your roll purchasing needs!