In industrial production, the hardness of the roller has a crucial impact on its durability and performance. Whether in metal processing, printing, or in papermaking, plastic processing and other industries, industrial rollers play a key role. Among the surface treatment technologies of these industrial rollers, chrome plating and tungsten carbide coating are the two most common options. So, which one is harder, chrome-plated roller or tungsten carbide coated roller? 

This article will explore the hardness characteristics of the two in depth to help readers better understand the advantages and applications of these two surface treatment technologies.

What is the hardness of chrome-plated rollers?

Chrome-plated rollers refer to rollers that are plated with a layer of chromium metal on the surface, usually using an electroplating process. The main function of this chrome layer is to improve the wear resistance and corrosion resistance of the roller, while giving it a smooth surface and improving the surface quality of the product. The hardness of the chrome layer is usually between HV800 and HV1000, and the specific hardness will vary depending on factors such as coating thickness and process parameters.

What is the relationship between electroplating process and hardness?

The electroplating process of chrome plating determines its hardness level. Generally speaking, the longer the electroplating time, the thicker the coating and the higher the hardness. In addition, parameters such as the composition and temperature of the electrolyte and the size of the process current will also affect the hardness of the final coating.

What are the advantages of chrome-plated rollers?

Chrome-plated rollers have high hardness, smooth surface and corrosion resistance, and are the first choice in many industrial fields. However, although the chrome plating layer has a high hardness, its toughness is relatively poor, and it is more likely to have microcracks due to stress concentration. Under high-intensity continuous use, the chrome-plated roller may have peeling of the coating, which will affect its service life.

What is the hardness of tungsten carbide coated rollers?

Tungsten carbide coated rollers refer to rollers on which a layer of tungsten carbide coating is applied by thermal spraying, laser cladding and other process methods. As a superhard material, tungsten carbide usually has a hardness between HV1200 and HV2000, which far exceeds the hardness of the chrome plating layer. This high hardness gives tungsten carbide coated rollers extremely high wear resistance and impact resistance.

What is the relationship between thermal spraying process and hardness?

The choice of thermal spraying process has a direct impact on the hardness of tungsten carbide coating. Plasma spraying, HVOF and other technologies can effectively improve the density and bonding strength of the coating, thereby further improving the hardness of the coating. In addition, the thickness of the coating, the purity of the spraying material and the parameter settings of the spraying equipment will also affect the final hardness of the tungsten carbide coating.

What are the advantages of tungsten carbide coated rollers?

Tungsten carbide coated rollers have extremely high hardness and excellent wear resistance, and are especially suitable for mechanical equipment working under high load and high temperature conditions. In addition, tungsten carbide coatings also have excellent corrosion resistance and high temperature resistance, and can maintain stable physical properties under extreme conditions.

Industrial Roller Chrome Plating VS. Tungsten Carbide Coated Roller: Which is Harder?

From the above analysis, it can be seen that the hardness of tungsten carbide coated rollers is significantly higher than that of chrome-plated rollers. The difference in hardness between the two is mainly due to the characteristics of the material itself and the difference in its processing technology. Specifically, the hardness of tungsten carbide coating ranges from HV1200 to HV2000, which is significantly higher than HV800 to HV1000 of chrome coating.

Wear resistance comparison

The direct impact of hardness is wear resistance. Under the high-hardness tungsten carbide coating, the surface of the roller can effectively resist friction and wear in long-term use, and is suitable for working conditions with extremely high wear resistance requirements for the roller. Although chrome-plated rollers also have certain wear resistance, their wear resistance may not be as good as tungsten carbide coated rollers under ultra-high load conditions.

Impact resistance comparison

High-hardness materials usually mean more brittle properties. However, the process technologies used in tungsten carbide coated rollers, such as laser cladding, can enhance the toughness of the coating while maintaining high hardness, thereby improving impact resistance. Chrome-plated rollers perform well in some low-to-medium load applications because of the balanced hardness and toughness of their coatings, but under high impact loads, the coatings may crack or peel off.

Service life comparison

Due to the better hardness and wear resistance of tungsten carbide coated rollers, their service life is usually longer than that of chrome-plated rollers. Especially in some harsh working conditions, tungsten carbide coated rollers can better resist wear and impact, thereby reducing maintenance costs and downtime. However, the initial cost of tungsten carbide coating is higher, which is also a factor that enterprises need to consider when choosing.