The reason why small-size cylindrical roller bearings are made of carburized steel

Apr 09, 2024

The reason why small-size cylindrical roller bearings are made of carburized steel involves considerations in many aspects, including the physical properties of the material, the working conditions of the bearing, service life, and cost-effectiveness, as well as the fit between the bearing and the shaft. Here is a detailed analysis of this issue:

First, let's take a look at the basic characteristics of carburized steel. Carburized steel is a surface-hardened material that significantly improves the wear resistance of steel by injecting carbon elements into the surface of steel with a low carbon content and then quenching it. This treatment method allows the surface hardness of carburized steel to reach HRC58-63 or even higher, thus having the ability to resist wear and impact. At the same time, the internal structure and toughness of carburized steel are also maintained, allowing it to maintain stable operation in high-load and high-speed working environments.

Despite their smaller size, small-size cylindrical roller bearings need to withstand high radial loads, impact loads, and high-speed rotation in many applications. Especially in some precision machinery, high-speed running equipment, and heavy-load workplaces, the performance of small-size cylindrical roller bearings is directly related to the stability and service life of the entire mechanical system. Therefore, it is particularly important to choose a material with high strength, high hardness, and good wear resistance to manufacture these bearings.

The high hardness and wear resistance of carburized steel make it an ideal material for manufacturing small-size cylindrical roller bearings. Under high-speed rotation and heavy load conditions, carburized steel bearings can effectively resist wear and deformation and maintain stable geometry and accuracy, thereby ensuring the normal operation of mechanical systems. In addition, an update in the internal structure of carburized steel can also increase the load-bearing capacity of the steel, allowing it to adapt to more demanding working conditions.

In addition to its physical properties, the processing properties of carburized steel are also one of the important reasons why it is selected as a bearing material. Although carburized steel has a high surface hardness, it still maintains the characteristics of ordinary steel internally, so it can be processed by cutting and surface grinding. It enables carburized steel bearings to achieve high precision and surface quality during manufacturing, further improving bearing performance and reliability.

In addition, from a cost-effectiveness perspective, carburized steel bearings also have clear advantages. Although the processing and heat treatment process of carburized steel is relatively complex, its excellent performance and service life make this bearing highly cost-effective. During long-term use, carburized steel bearings can reduce the frequency of repairs and replacements, reduce maintenance costs, and improve the overall economic benefits of the mechanical system.

In addition, small-size cylindrical roller bearings have extremely high requirements for material purity and organizational uniformity in some special applications, such as aerospace, precision instruments, and other fields. Carburizing steel can optimize the microstructure of steel to meet the needs of these special applications by precisely controlling the infiltration and distribution of carbon elements.

Of course, for small-size cylindrical roller bearings with different specifications and uses, the material selection may also be different. When selecting bearing materials, factors such as the bearing's working conditions, load characteristics, speed requirements, and service life need to be comprehensively considered to determine the most suitable material type. With the fast development in the field of materials engineering, more new materials may be used in the manufacturing of small-size cylindrical roller bearings in the future to meet higher performance and more stringent requirements.

The picture above is the carburized steel four-row cylindrical roller bearing F-800426 designed by FV. The material is SAE3311 and is used for the work rolls of rolling mills.

One point that cannot be ignored is that there is a close relationship between the use of carburized steel materials for small-size cylindrical roller bearings and clearance fit. This relationship is mainly reflected in the following aspects:

First of all, the characteristics of carburized steel make small-size cylindrical roller bearings have higher hardness and wear resistance so that they can adapt to relative motion in clearance fits. Clearance fit allows a certain relative movement between the hole and shaft. At the same time, the high hardness and wear resistance of carburized steel can ensure that the bearing is not easily worn during relative movement and maintains stable geometry and accuracy. Therefore, the use of carburized steel enhances the reliability and durability of small-size cylindrical roller bearings in clearance fits.

Secondly, the impact of carburized steel material on clearance fit is also reflected in its control of fit tolerance. The fit tolerance refers to the sum of the tolerance zones of the shaft holes that make up the fit, which allows the variation in clearance or interference and affects the tightness of the fit. The high-precision machining capabilities of carburized steel make the tolerance zone of the bearing more precise, allowing for better control of the size and scope of the clearance fit. This precise control helps ensure the accuracy of the fit between the bearing and the shaft, improving the stability and performance of the mechanical system.

Third, the carburized steel material also plays a positive role in the lubrication and error compensation of clearance fit. An important function of clearance fit is to store lubricating oil to compensate for various errors. The high hardness and wear resistance of carburized steel make the bearing surface smoother, which is beneficial to the even distribution of lubricating oil and reducing friction. At the same time, the elastic modulus and toughness of carburized steel can also effectively absorb and compensate for errors and impacts during the fitting process, ensuring the smooth operation of the mechanical system.

To sum up, the reasons why small-size cylindrical roller bearings are made of carburized steel mainly include its excellent physical properties, good processing performance, cost-effectiveness, and special application requirements. The high hardness, wear resistance, and load-bearing capacity of carburized steel enable small-size cylindrical roller bearings to maintain stable operation in various harsh working environments, improving the performance and reliability of mechanical systems. At the same time, the processing performance and cost-effectiveness of carburized steel also make this bearing have widespread promotion value in practical applications. The characteristics of carburized steel material enable the bearings to adapt to relative motion in clearance fits, improving fit accuracy and reliability. At the same time, carburized steel materials also play a positive role in the control of fit tolerances, lubrication, and error compensation, further improving the performance and stability of mechanical systems. Therefore, when selecting materials for small-size cylindrical roller bearings, carburized steel is an ideal choice, which can meet the clearance fit requirements and improve overall performance.

The picture above is a four-row cylindrical roller bearing Z-580510.ZL. The inner ring is made of carburized steel G20CrNi2MoA, which is used for the roll neck and matches the roll neck clearance.

The above analysis aims to deeply explore the reasons why small-size cylindrical roller bearings are made of carburized steel and elaborate on its rationality and advantages from multiple dimensions. However, there may be some special situations or complex factors that need to be considered in actual applications, so comprehensive analysis and judgment must be made based on actual conditions during the specific design and manufacturing process.

In short, the use of carburized steel for small-size cylindrical roller bearings is based on considerations such as its excellent physical properties, processing performance, cost-effectiveness, and special application requirements. This choice can not only meet the performance requirements of the bearings under various working conditions but also improve the overall performance and economic benefits of the mechanical system. With the expansion of applications, more innovations in materials and designs of small-size cylindrical roller bearings will emerge in the future.