China 6304z Bearing Manufacturer & Supplier

Engineering In-Depth: The 6304z Deep Groove Ball Bearing

A comprehensive technical analysis of the 6304z bearing architecture, performance parameters, and material science.

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Standard Dimensional Profile

The 6304z Deep Groove Ball Bearing features a precise standard physical profile: an inner diameter of 20mm, an outer diameter of 52mm, and a width of 15mm. Designed for high radial load applications, the internal race geometry accommodates optimized contact angles, ensuring robust distribution of stress under peak torque loads.

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Z-Shield Protection

The single-metal "Z" shield is cold-rolled steel stamped directly into the outer ring groove. This configuration offers superior dust prevention while preventing grease purge, retaining optimum lubrication without adding dynamic friction torque, allowing speeds up to 12,000 RPM under ideal conditions.

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GCr15 High-Carbon Steel

Constructed entirely of premium-grade GCr15 bearing steel, our 6304z units undergo standard vacuum degassing and rigorous heat-treatment to achieve a surface hardness of 60 to 65 HRC. This enhances fatigue life and reduces structural elastic deformation under cyclical stress.

Model Parameter	Dimension (Metric)	Limiting Speed (Grease)	Dynamic Load (Cr)	Static Load (Cor)	Vibration & Noise Class
6304z	20mm x 52mm x 15mm	12,000 RPM	15.9 kN	7.8 kN	Z2V2 / Z3V3 Premium Level
6304-2Z (ZZ)	20mm x 52mm x 15mm	11,000 RPM	15.9 kN	7.8 kN	Z3V3 Ultra-Silent Available

Note: The internal clearance (radial clearance) of the 6304z series can be customized to CN (Normal clearance for general applications), C3 (increased clearance for thermal compensation at high operating temperatures), or C4 (heavy duty applications). Proper clearance management directly influences the bearing lifecycle by preventing premature micro-spalling.

China Factory 4.0: Sill Bearing & Anhui TOPB Manufacturing Integration

Combining structural supply-chain advantages with state-of-the-art automated manufacturing processes.

Sill Bearing Factory: Strategic Logistics and Modern Infrastructure

Established strategically within the high-tech industrial cluster of the Hangzhou Bay New Zone, our facility benefits from unmatched domestic and international logistics infrastructure. Located in close proximity to the twin global shipping hubs—Ningbo Port and Shanghai Port—we maintain lead times far superior to landlocked manufacturing hubs. With rapid access to the Hangzhou-Ningbo Expressway, the 329 State Line, and the Hangzhou-Ningbo Railway, regional freight transfers are optimized to support just-in-time delivery schedules. We are positioned only 90 minutes from Hangzhou Xiaoshan International Airport and Ningbo Lishe Airport.

"To expand global production capacity and meet growing demand, our new manufacturing subsidiary, Anhui TOPB IMP. & EXP. Co., Ltd., is under construction. Once commissioned, our annual production capacity will increase by over $20 million."

Our factories specialize in designing, engineering, and manufacturing Deep Groove Ball Bearings (ranging from ￠4mm up to ￠120mm), Tapered Roller Bearings, and bespoke non-standard bearings utilizing premium GCr15 raw materials.

20M+

Annual Capacity Expansion ($)

100%

Inspection Acceptance Rate

90 Min

Access to International Airports

4-120mm

Precision Outer Diameters

Technology Roadmap & Future Horizons

Innovating next-generation tribological designs, smart sensors, and advanced carbon-neutral manufacturing processes.

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E-Mobility Optimization

Developing ultra-high-speed bearings designed specifically for electric vehicle (EV) drivetrains. By incorporating specialized ceramic (silicon nitride) rolling elements and advanced polyurea greases, we mitigate electrical pitting and support rotational speeds exceeding 20,000 RPM.

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Bio-Degradable Lubricants

Committed to global ESG initiatives, our R&D center is formulating synthetic esters and bio-greases that offer thermal stability between -40°C and +150°C, drastically reducing the environmental footprint of heavy agricultural and industrial operations.

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Fully Automated Manufacturing

Transitioning our Anhui TOPB and Hangzhou Bay lines to integrated IoT setups. This involves closed-loop control of grinding geometries, machine-learning-based acoustic screening, and automated robotic handling to guarantee consistency in dimensions.

Macro-Industry Bearing Solutions

Where mechanical stress meets engineering solutions: tailored application pathways for the 6304z bearing.

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Household Appliances

For washing machines, vacuum cleaners, and ventilation fans. Our SILL brand focuses on low vibration and friction, high accuracy, and low-noise profiles (Z3V3 grade) to guarantee quiet performance.

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Automotive Components

Widely applied in alternators, water pumps, tensioner pulleys, and auxiliary motors where high ambient heat and dynamic belt tension demand robust axial and radial load capabilities.

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Agricultural Machinery

Fitted inside tractors, harvesters, and tilling gear. In these harsh environments, the 6304z metal shield acts as an primary barrier against crop residues, soil particles, and moisture ingress.

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Medical Instruments

Integrated in laboratory centrifuges, analytical equipment, and diagnostic pumps requiring minimal friction torque, smooth rotation, and compatibility with cleanroom protocols.

Meeting the Demands of Global Enterprise Procurement

Providing supply stability, customization capacity, and international quality management certifications.

Sill Bearing Warehousing and Quality Testing

The Five-Stage Quality Verification Process

To achieve a 100% acceptance rate, Sill Bearing Factory adheres to a comprehensive, multi-layered quality control framework:

Raw Material Initial Inspection: Chemical composition analysis (spectroscopy) and macro-inclusions inspection of incoming GCr15 bearing steel batches.
Operators' Self-Inspection: In-line micrometric control during grinding, honing, and polishing operations to prevent process deviation.
Inspectors' Full Inspection: 100% automated electronic inspection of dimensions, roundness, and raceway concentricity.
Chief Inspectors' Sampling: Critical metallurgical audits, hardness testing (HRC), and acoustic noise testing (BVT) of random output batches.
Final Ex-Factory Inspection: Visual auditing, dynamic torque verification, and packaging seal integrity assessments before container seal.

Our dedicated brands, SILL and NETB, have secured recognition across markets including the United States, Brazil, Switzerland, the United Arab Emirates, Iran, Turkey, Pakistan, Malaysia, Bangladesh, Egypt, and Nigeria.

Industrial Classification & Product Portfolio

A breakdown of our core bearing designs, each optimized for specific kinetic and kinematic applications.

Deep Groove Ball Bearings

Deep groove ball bearings are versatile, self-retaining bearings with a deep groove raceway that allows them to handle both moderate radial and axial loads in both directions. Key features include their suitability for high-speed applications, low friction, reduced noise and vibration, and low maintenance needs. They are widely used in various industries and are available in single and double-row designs with open or sealed variants.
Tapered Roller Bearings

Tapered roller bearings are separate bearings, and the inner and outer rings of the bearing have tapered raceways. This type of bearing is divided into different structural types such as single row, double row and four row tapered roller bearings according to the number of rows of rollers installed.
Angular Contact Ball Bearings

Angular contact ball bearings are mainly subjected to large one-way axial loads, and the greater the contact angle, the greater the load bearing capacity.
Radial Needle Bearings

The combination of the radial needle bearing and the thrust bearing component is a combined needle roller bearing, which has a compact structure, high rotation precision, and can withstand a certain axial load while receiving a high radial load.

Featured Product Series

A closer look at our high-demand industrial bearing classifications.

6900 Series Bearings

6800 Series Bearings

6300 Series Bearings

6200 Series Bearings

Technical Q&A: 6304z Ball Bearings & Supplier Standards

Detailed technical answers for industrial engineers, procurement officers, and machinery designers.

Q1: What is the main difference between 6304z and 6304zz deep groove ball bearings?

The suffix "Z" designates a single-sided steel shield, whereas "ZZ" represents double-sided steel shields. The single shield (6304z) allows visual inspection and manual lubrication from the unshielded side during assembly and is typically installed inside dynamic housings where a lubricating oil bath is shared. The 6304zz is greased-for-life, preventing the penetration of contaminants from both sides.

Q2: Why is the GCr15 alloy steel preferred for the 6304z bearing?

GCr15 (comparable to AISI 52100 or DIN 100Cr6) is a high-carbon chromium alloy steel containing approximately 1% carbon and 1.5% chromium. Its balanced carbon and chromium content provides high contact fatigue resistance, exceptional dimensional stability, and wear resistance post-hardening, which is crucial for deep groove configurations.

Q3: How do you guarantee the Z3V3 vibration and noise grades in production?

Our factory employs automated vibration velocity (V) and acceleration (Z) analyzers (such as the BVT-1 and S910) to inspect every bearing. We achieve the Z3V3 standard by superfinishing the ball track raceways, using high-precision steel balls, and applying clean grease under strict dust-free conditions.

Q4: Can you provide custom clearances like C3 or C4 for high-temperature operations?

Yes, we provide customizable clearances. If your equipment operates above 120°C (such as inside glass kilns or exhaust fans), a C3 or C4 clearance prevents seizure by allowing for the thermal expansion of the inner ring relative to the outer ring.

Q5: What are your shipping lead times for container orders from Ningbo or Shanghai?

Due to our prime location in Hangzhou Bay New Zone, containerized shipments can reach Ningbo Port or Shanghai Port in under 2 hours. Stocked bearings can be dispatched within 7 days, whereas custom OEM orders are fulfilled within 25 to 40 days, including complete metallurgical testing reports.