Ningbo Zhonggao Rubber & Plastic Manufacturing Co., Ltd. is one of the most reliable manufacturers and suppliers of bonded seal in China. The company has world-leading production equipment and strong manufacturing capabilities. Welcome to wholesale custom made bonded seal from our factory.
What Are Bonded Seals
Bonded seals are sealing components consisting of a metal washer and a bonded elastomer sealing element. They provide reliable static sealing for threaded connections by combining the strength of metal with the flexibility of rubber. Bonded seals are widely used in hydraulic, pneumatic, and industrial fluid systems and are available in various materials, standards, and configurations for different applications.
Types of Custom Bonded Seals We Manufacture
As a bonded seal manufacturer, we supply bonded seals in different material combinations and international size standards based on application requirements, supporting both standard products and OEM customization. Our engineering and manufacturing capabilities cover material selection, product design, tooling development, precision manufacturing, and quality inspection, allowing us to supply bonded seals for a wide range of industrial applications.
- Carbon Steel Bonded Seals: Suitable for general hydraulic and industrial sealing applications where cost-effective performance and reliable strength are required.
- Stainless Steel Bonded Seals: Recommended for corrosive environments requiring improved corrosion resistance and extended service life.
- NBR Bonded Seals: Suitable for hydraulic oils, lubricants, and general industrial fluids.
- FKM Bonded Seals: Recommended for higher temperatures, fuels, chemicals, and aggressive industrial media.
- EPDM Bonded Seals: Suitable for water, steam, glycol-based fluids, and weather-resistant sealing applications.
- Silicone Bonded Seals: Recommended for applications requiring flexibility across a wide operating temperature range.
- Brass Bonded Seals: Suitable for applications requiring good corrosion resistance, machinability, and compatibility with specific industrial media.
- Aluminum Bonded Seals: A lightweight option for applications where weight reduction and corrosion resistance are important.
- Metric Bonded Seals: Manufactured according to commonly used metric dimensions for a wide range of industrial and hydraulic sealing applications.
- BSP Bonded Seals: Designed for British Standard Pipe-threaded fittings that require reliable static sealing performance.
- Self-Centering Bonded Seals: Feature an integrated locating lip that simplifies installation and improves alignment during assembly.
Various customization options are available to support different project requirements.
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Capability |
What Can Be Customized |
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Size |
ID, OD, Thickness, Metric & BSP Dimensions |
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Material Combinations |
Carbon Steel, Stainless Steel, Brass, Aluminum, NBR, FKM, EPDM, Silicone |
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Surface Finish |
Zinc-Plated, Stainless Steel Finish, Project-Specific Treatment |
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Standards |
Metric & BSP |
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Packaging |
Standard Packaging, Custom Labels, OEM Packaging |
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Order Type |
Samples, Trial Orders, Bulk Orders, OEM Projects |
Industry Applications
Hydraulic Systems
Bonded seals are widely used in hydraulic systems to provide reliable static sealing for threaded connections under high pressure and continuous operating conditions.
Construction Equipment
Construction machinery uses bonded seals in hydraulic circuits to help prevent fluid leakage and maintain reliable sealing in demanding operating environments.
Agricultural Machinery
Agricultural equipment relies on bonded seals to support dependable sealing in hydraulic components exposed to vibration, dust, moisture, and changing weather conditions.
Oil & Gas
Bonded seals are used in oil and gas systems where sealing components must withstand high pressure, aggressive media, and harsh industrial environments.
Fluid Power Systems
Fluid power equipment uses bonded seals to improve sealing performance in pumps, valves, and hydraulic fittings carrying pressurized fluids.
General Industrial Equipment
Bonded seals are suitable for a wide range of industrial machinery that requires reliable sealing of threaded ports, connectors, and fluid transmission systems.
Equipment Applications
Hydraulic Fittings
Bonded seals provide dependable sealing between threaded fittings and mating surfaces to reduce leakage in hydraulic connections.
Hydraulic Valves
Hydraulic valves use bonded seals to maintain sealing integrity around threaded ports operating under pressure and repeated service cycles.
Hydraulic Pumps
Bonded seals help prevent hydraulic fluid leakage at threaded interfaces, supporting stable pump operation and long-term sealing performance.
Hydraulic Cylinders
Hydraulic cylinders apply bonded seals to threaded connections where reliable static sealing is required under continuous pressure.
Power Units
Hydraulic power units use bonded seals to seal threaded ports and fluid connections throughout integrated hydraulic systems.
Industrial Pipe Connections
Bonded seals are used in industrial piping systems to provide effective sealing for threaded joints handling hydraulic oil, lubricants, and other industrial fluids.
Why Bonded Seals Matter for Your Application
Bonded seals combine the strength of a metal washer with the sealing performance of an elastomer insert, helping improve sealing reliability, reduce leakage risks, and support stable operation in demanding applications.
Multi-layer structure design
Our bonded seal is usually composed of a metal frame (such as stainless steel, copper) and a non-metallic sealing layer rubber. The metal layer provides support strength, and the non-metallic rubber layer ensures sealing.
Excellent sealing performance
Non-metal parts generally fill microscopic uneven surfaces, which are very suitable for filling tiny defects in flanges or joint surfaces to prevent medium leakage.
Chemical corrosion resistance
PTFE material is resistant to acid and alkali, and can adapt to a variety of media such as oil, water vapor, acid and alkali.
Anti-creep and resilience
The metal frame of the bonded seal can prevent the non-metallic material from plastic deformation under long-term pressure, thereby extending the service life.
Technical Parameters
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Parameter Category |
Technical Item |
Reference Value / Range |
Notes |
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Thermal Performance |
Operating Temperature |
NBR: -30°C to +100°C FKM: -20°C to +200°C |
Depends on Rubber Material |
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Short-Term Temperature |
Up to +230°C (FKM) |
Short-duration Exposure Only |
|
|
Mechanical & Physical Properties |
Rubber Hardness |
70±5 Shore A (Typical) |
Custom Hardness Available |
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Metal Washer Material |
Carbon Steel / Stainless Steel (Typical) |
Selected According to Application |
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Compression Set |
Material-dependent |
Affects Long-term Sealing |
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Pressure & Sealing Parameters |
Working Pressure |
Up to 40 MPa (Typical Hydraulic Applications) |
Depends on Installation Conditions |
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Sealing Method |
Axial Static Sealing |
Used for Hydraulic Threaded Connections |
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Thread Compatibility |
Metric / BSP |
Other Standards Available upon Request |
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Chemical Properties |
Oil Resistance |
Excellent (NBR / FKM) |
Suitable for Hydraulic Oils |
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Chemical Compatibility |
Depends on Elastomer |
Confirm Media Compatibility before Selection |
|
|
Corrosion Resistance |
Stainless Steel Version Available |
Suitable for Corrosive Environments |
Customized Specifications
Bonded seal specifications can be configured to match different equipment requirements, sealing conditions, and supply preferences. The following options support flexible selection for both standard and OEM projects.
Custom bonded seals can be manufactured according to drawings, samples, thread specifications, or sealing requirements to ensure reliable installation and sealing performance.
ID & OD: Inner diameter and outer diameter are customized to match threaded fittings, bolts, ports, and sealing interfaces.
Thickness: Selected according to sealing pressure, installation space, compression requirements, and operating conditions.
Metric: Manufactured to metric dimensions for hydraulic systems and industrial equipment using metric threaded connections.
BSP Dimensions: Produced to BSP thread dimensions for compatibility with British Standard Pipe sealing applications.
Bonded seals can be supplied in different structural designs according to installation requirements and sealing conditions.
Standard Design: Suitable for conventional threaded sealing applications.
Self-Centering Design: Features a locating lip to simplify installation and improve alignment during assembly.
Custom bonded seals can be supplied with different metal and elastomer combinations to meet specific application requirements.
Metal Washer: Carbon steel, stainless steel, brass, or aluminum can be selected according to strength, corrosion resistance, and application requirements.
Elastomer: NBR, FKM, EPDM, or silicone can be selected according to media compatibility, operating temperature, and sealing performance.
Material Matching: Suitable metal and rubber combinations are recommended based on the actual operating environment and equipment requirements.
Surface finishes can be selected according to corrosion resistance, appearance, and application requirements.
Zinc-Plated: Suitable for general industrial applications requiring corrosion protection.
Stainless Steel Finish: Provides natural corrosion resistance without additional coating.
Project-Specific Treatment: Surface treatments can be customized according to customer specifications.
Custom bonded seals can be manufactured according to international thread standards or customer-specific requirements.
Common Standards: Metric and BSP
Custom Dimensions: Customized diameters, thicknesses, tolerances, and sealing configurations according to customer drawings.
Sample-Based Matching: Existing bonded seal samples can be reverse-engineered when technical drawings are unavailable.
Packaging solutions can be customized according to procurement methods, logistics requirements, and supply chain management.
Standard Packaging: Suitable for routine inventory supply and bulk industrial orders.
OEM Labeling: Custom labels, part numbers, and brand identification are available for OEM projects.
Protective Packaging: Individual or customized packaging options help protect products during storage and international transportation.
Manufacturing Process
We manufacture bonded seals through a controlled production process according to seal dimensions, material combinations, performance requirements, and application conditions to ensure consistent sealing quality and product reliability.
Step 1 Metal Washer Preparation
Metal washers are stamped, machined, and surface-treated according to the required dimensions, material specifications, and corrosion protection requirements.
Step 2 Rubber Bonding
Metal washers are stamped, machined, and surface-treated according to the required dimensions, material specifications, and corrosion protection requirements.
Step 3 Vulcanization & Forming
The bonded seal is vulcanized under controlled temperature and pressure to achieve the required mechanical properties and sealing integrity.
Step 4 Final Inspection
Each bonded seal is inspected for dimensions, surface quality, rubber bonding integrity, and overall sealing performance before shipment.
Our controlled manufacturing process enables us to supply standard and custom bonded seals for hydraulic, fluid power, construction equipment, and general industrial sealing applications.
Quality Control
To help ensure that each custom Bonded seals matches your drawing, sample, equipment interface, and sealing requirements, we apply strict quality checks from material confirmation to final packaging. This helps reduce production errors, improve installation fit, and support more consistent repeat orders.
- Material Confirmation: checks the selected Bonded seal type, metal material, and rubber material before production
- Drawing Review: verifies size, hole position, shape, and tolerance to reduce production errors
- Dimension Inspection: checks ID, OD, thickness, thread standard dimensions for proper installation fit
- Surface Check: reviews burrs, coating quality, rubber bonding condition, and edge quality to support better sealing performance
- Batch Check: confirms quantity, labeling, and packaging consistency for easier storage, delivery, and repeat orders
Order Support from Sample to Delivery
We support custom Bonded seal projects from sample confirmation to mass production and delivery. Whether you need a trial sample, repeated wholesale supply, OEM packaging, or technical assistance before production, our team can help make the sourcing process more efficient and reliable.
Sample support before bulk production.
Packaging by size, material, drawing number or batch.
Support for wholesale and bulk Bonded seal orders.
Technical consultation for material selection and drawing confirmation.
Assistance with required inspection or audit documents when available.
Send Inquiry for Custom Bonded Seals
FAQ
Q: How Does a Bonded Seal Work?
A: A bonded seal combines a metal washer with an elastomer insert. Under compression, the rubber deforms to create a leakproof seal while the metal prevents over-compression.
Q: Bonded Seal vs Copper Washer: What Is the Difference?
A: Bonded seals provide elastic sealing with higher reliability, while copper washers rely on metal deformation and are mainly used in high-temperature static sealing.
Q: Bonded Seal vs O-Ring: Which Should I Choose?
A: Choose bonded seals for threaded hydraulic fittings. O-rings are better for groove sealing in dynamic or static sealing applications.
Q: Which Bonded Seal Material Is Best for Different Applications?
A: NBR suits hydraulic oil, FKM fits fuel and high temperatures, EPDM handles water, and silicone performs across wide temperature ranges.
Q: How Do I Choose the Right Bonded Seal Size?
A: Select bonded seal dimensions according to thread standard, fitting size, groove dimensions, and operating conditions to ensure proper sealing performance.
Q: What Bonded Seal Size Standard Should I Choose?
A: Choose Metric (including German Metric and French Metric), BSP, Inch bonded seals according to your equipment standard and fitting specifications.
Q: What Pressure Can a Bonded Seal Withstand?
A: Pressure capability depends on material, size, installation quality, and application conditions. Proper selection ensures reliable sealing in high-pressure systems.
Q: How Should a Bonded Seal Be Installed?
A: Install bonded seals on clean, undamaged sealing surfaces with proper tightening torque to prevent leakage and maximize sealing performance.
Q: Are Bonded Seals Reusable?
A: Bonded seals are generally recommended for single use. Replacing them after disassembly helps maintain sealing reliability and reduces leakage risks.
Q: Can You Supply Custom Bonded Seals for OEM Projects?
A: Yes. We supply custom bonded seals based on drawings or samples, supporting OEM projects with customized sizes, materials, international standards, and packaging.
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