Carbon steel deep groove ball bearings
Carbon steel deep groove ball bearings are manufactured from carbon structural steel or carbon tool steel. While they offer slightly lower wear resistance and service life than bearings made from high-carbon chromium bearing steel, they offer advantages such as low cost and excellent processability. They are widely used in general-purpose machinery applications where precision and service life are less critical, such as agricultural machinery, textile machinery, and household appliances. Their structure is identical to that of standard deep groove ball bearings, consisting of an inner ring, outer ring, steel balls, and a cage. They can withstand radial and bidirectional axial loads and exhibit excellent self-aligning properties. Application data from an agricultural machinery parts manufacturer shows that deep groove ball bearings made from 45 steel can achieve a service life of over 2,000 hours in tractor transmissions, fully meeting the requirements of agricultural production.
The material selection for carbon steel deep groove ball bearings requires a balance between performance and cost. Commonly used carbon steel materials include high-quality carbon structural steel (such as 45 steel) and carbon tool steel (such as T10A). After quenching and tempering, 45 steel exhibits excellent strength and toughness, reaching a hardness of 220-250 HB, making it suitable for bearings with medium loads. After quenching and tempering, T10A steel achieves a surface hardness of 55-60 HRC, offering superior wear resistance compared to 45 steel, making it suitable for applications requiring high wear resistance. Compared to high-carbon chromium bearing steel (GCr15), carbon steel has poorer hardenability and a lower core hardness after quenching. Therefore, the load capacity of carbon steel deep groove ball bearings is approximately 60%-70% of that of GCr15 bearings. An electric motor manufacturer used T10A steel bearings in fan motors. By optimizing the heat treatment process, the bearings’ wear resistance was improved by 15%, while the cost was reduced by 30% compared to GCr15 bearings.
The machining process for carbon steel deep groove ball bearings requires tailoring to the material’s characteristics. The inner and outer ring machining process is: forging → annealing → rough turning → quenching → tempering → finish turning → grinding. Due to carbon steel’s high thermal conductivity, a rapid cooling rate is required during quenching. 45 steel is typically water quenched, while T10A steel is oil quenched to prevent cracking. The tempering temperature is determined by the required hardness, generally between 180-220°C, to ensure the bearing components remain within the specified hardness range. Steel balls are typically cold-formed. 45 steel balls undergo quenching and tempering, achieving a hardness of 50-55 HRC and a surface roughness of Ra 0.8μm. Cages are typically made of low-carbon steel (such as 08F) and formed by stamping, resulting in a significantly lower cost than brass cages. A small bearing manufacturer, while machining 45 steel deep groove ball bearings, improved the quenching hardness uniformity of the inner ring by 20% by improving the cooling medium during quenching, thereby reducing grinding wheel consumption during the grinding process.
The precision grade of carbon steel deep groove ball bearings is closely related to their application. According to the GB/T 307.1 standard, carbon steel deep groove ball bearings are typically available in grades 0 (normal) and 6. Grade 0 bearings have greater radial clearance and lower rotational accuracy, making them suitable for low-speed applications, such as washing machine motors. Grade 6 bearings, through precision grinding, achieve improved radial clearance and rotational accuracy, making them suitable for equipment with high vibration and noise requirements, such as blowers. Compared to high-precision bearings, carbon steel deep groove ball bearings have relatively loose dimensional and form tolerances. The inner ring inner diameter tolerance is generally H7, the outer ring outer diameter tolerance is H7, and the roundness error does not exceed 0.01mm. A household refrigerator manufacturer uses grade 0 carbon steel deep groove ball bearings. By optimizing the assembly process, they have reduced the vibration noise of their compressors to below 45 decibels, meeting the noise standards for household appliances.
The use and maintenance of carbon steel deep groove ball bearings require careful consideration of environmental factors. Carbon steel has poor corrosion resistance and is prone to rusting in humid or dusty environments. Therefore, necessary protective measures are necessary, such as applying anti-rust oil to the bearing surface and installing dust covers or seals. During use, the bearings should be protected from excessive impact loads. Carbon steel bearings have poor impact resistance, and excessive impact loads can cause cracking in the inner or outer rings. During regular maintenance, check the bearing clearance and wear. If the radial clearance exceeds 1.5 times the initial clearance, the bearing should be replaced promptly. A textile machinery factory has extended the life of its spinning frame bearings by 25% and reduced equipment maintenance costs by regularly cleaning and regreasing carbon steel bearings. With the manufacturing industry’s emphasis on cost control, the application of carbon steel deep groove ball bearings in general machinery will become more widespread. Through material modification and process optimization, their performance will continue to improve, providing reliable support for low-cost machinery and equipment.
