Premium O-Ring Manufacturer & Supplier in China – Reliable Global Supply
Savvy Rubber is a trusted o-ring manufacturer and supplier in China, serving global industries with reliable sealing solutions. We stock millions of standard metric and imperial o-rings in NBR and FKM (Viton®), offering low MOQ and fast global door-to-door delivery. Custom orders are welcome, with competitive tooling costs and short lead times.
O-Ring Products
Besides standard o-rings, we also manufacture encapsulated o-rings, backup rings, x-rings, o-ring cord, o-ring kits, etc. Additionally, as we are a factory, we can produce custom o-rings at very low mold and product costs, while maintaining good quality.
O-Ring Overview
O-Ring Materials
O-rings can be made of rubber, metal, or other materials, but rubber is the most commonly used. Savvy can produce popular rubber compound o-rings, as well as some special compounds. Depending on working conditions, different materials need to be carefully selected to achieve the best sealing. The most commonly used o-ring materials are NBR, FKM, Silicone, and EPDM.
NBR is the first material we suggest. About 50% of o-rings worldwide are made from NBR compounds due to their good performance and low cost. Strong oil resistance is one of the biggest advantages of NBR o-rings.
FKM / Viton is an o-ring material with excellent overall performance and is widely used in various high-standard sealing applications. It was initially invented by DuPont and introduced under the trademark “Viton”. Over time, more and more people have come to refer to this material as Viton.
Silicone is increasingly used in the medical and food industries, especially FDA-grade silicone. It is tasteless, non-toxic, and resistant to both high temperatures and severe cold.
EPDM is a common o-ring material chosen for its exceptional resistance to weathering, ozone, and steam. It performs excellently in hot water and with brake fluids. Its key advantages lie in outstanding weatherability and good electrical insulation properties.
In addition to the popular rubber materials mentioned above, other compounds such as HNBR, FFKM, CR, NR, ACM, AFLAS, etc., are also widely used in various equipment for specific demanding conditions.
We produce high-quality o-rings in the following primary rubber materials at competitive prices.
O-Ring Material Selection Guide
Selecting the right rubber material is critical, as each rubber elastomer offers unique resistance to chemicals, temperatures, and physical demands. Use our comprehensive rubber compatibility guide below to compare properties and make an informed decision. Find the most cost-effective rubber o-ring solution for your application with Savvy Rubber.
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O-Ring Sizes
An o-ring is defined by three sizes: the Inside Diameter (ID), the Outside Diameter (OD), and the Cross-Section (CS) or Width (W). A standard o-ring size is typically specified using just the ID and CS (e.g., ID 20 x CS 2 mm).
Outside Diameter = Inside Diameter + Cross Section * 2
OD = ID + CS*2
Historically, different countries have established their own standard O-ring sizing systems, such as AS568 in the USA, BS1516 in the UK, DIN 3771 in Germany, JIS B 2401 in Japan, ISO 3601 internationally, and GB 3452.1 in China.
| Country | Standard | Cross Section / Width (mm) | ||||
|---|---|---|---|---|---|---|
| USA | AS568 | 1.78 | 2.62 | 3.53 | 5.33 | 6.99 |
| UK | BS1516 | |||||
| Universal | ISO 3601 | 1.8 | 2.65 | 3.53 | 5.3 | 7 |
| Germany | DIN 3771 | |||||
| France | NFT47 501 | |||||
| Sweden | SMS l586 | 1.6 | 2.4 | 3 | 5.7 | 8.4 |
| Japan | JIS B 2401 | 1.9 | 2 | 2.4 | 3.1 | 3.5 |
| 4 | 5.7 | 6 | 8.4 | 10 | ||
| Others | Preferred Metric Sizes | 1 | 1.5 | 2 | 2.5 | 3 |
| 3.5 | 4 | 4.5 | 5 | 5.5 | ||
| 6 | 7 | 8 | 10 | 12 | ||
O-Ring Hardness
The hardness of an o-ring is measured in Shore A, which can be easily determined using a Shore A durometer. Typically, o-rings have a hardness ranging from Shore A 50 to 90. A hardness of Shore A 70 is generally the most suitable for most applications, although silicone rubber is an exception, for which Shore A 60 is commonly used.
The selection of o-ring hardness is critical. If the hardness is too low, installation is easy, but the o-ring becomes prone to peeling, damage during handling and installation, extrusion, and even pressure burst. Conversely, if the hardness is too high, installation becomes difficult.
Generally, 50–60 is considered low hardness, 70–80 is medium hardness, and 88 (or 90) is high hardness. When the sealing pressure is between 30 and 60 MPa, the o-ring hardness should be 85–90. In some special cases, silicone o-rings can have a hardness as low as Shore A 25.
| Material | NBR | HNBR | FKM | FFKM | AFLAS | Silicone | FVMQ | EPDM | Neoprene | PU | PTFE |
| Hardness (Shore A) | 70 | 70 | 75 | 75 | 75 | 60-70 | 70 | 70 | 70 | 70-90 | 50 (D) |
| Color | Black | Green | Brown | Black | Black | Red | Blue | Black | Black | Yellow | White |
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O-Ring Colors
Savvy can produce o-rings in various colors for customers, who need to provide the standard RAL or Pantone color code. However, considering cost and ease of identification, it is generally recommended to choose from several commonly used colors. These include Black for NBR, Green for HNBR, Brown for FKM (Viton), Red, Translucent, or White for VMQ (Silicone), Blue for FVMQ, and Yellow for PU, among others. If you order a unique color that is not commonly used, it may increase the cost and require a higher MOQ with a longer delivery time.
If you need a custom color but do not have a specific color code, you can refer to the RAL color chart website at https://www.ralcolorchart.com.
O-Ring Tolerances
O-ring tolerances refer to the allowable deviations in its inner diameter (ID) and cross-sectional (CS) dimensions during the manufacturing process. Correctly understanding and applying these tolerances is crucial for ensuring optimal performance of the o-ring in sealing applications.
If the ID is below the lower tolerance limit, excessive stretching may be required during installation, leading to assembly difficulties or even damage. If the CS is below the lower tolerance limit, insufficient compression may prevent the formation of an effective seal, resulting in leakage.
Conversely, if the ID exceeds the upper tolerance limit, it may lead to insufficient pre-compression, similarly compromising the sealing effectiveness. If the CS exceeds the upper tolerance limit, it may cause over-compression, leading to extrusion, permanent set, or premature failure.
Therefore, strict control of manufacturing tolerances, ensuring both the ID and CS remain within specified limits, is a prerequisite for guaranteeing sealing reliability.
| CS (mm) | 0-1.79 | 1.80-2.64 | 2.65-3.54 | 3.55-5.29 | 5.30-6.99 | 7.00-8 | 8.01-10 | 10.01-15 | 15.01-25 | 25.01-100 |
| Tolerance | ± 0.07 | ± 0.08 | ± 0.09 | ± 0.1 | ± 0.13 | ± 0.15 | ± 0.2 | ± 0.25 | ± 0.35 | ± 0.45 |
The most widely adopted international standards for o-ring dimensional tolerances are the American AS568 series and the European ISO 3601-1. Currently, ISO 3601-1, with its metric system, clear tolerance grades (General Class B and Precision Class A), and global acceptance, is the industry-recognized standard.
At Savvy Rubber, our standard o-rings comply with both ISO 3601-1 Class B (General Grade) and AS568 tolerances, providing cost-effective and reliable sealing for most industrial applications.
For critical applications requiring extreme precision (e.g., high-pressure, dynamic, or vacuum environments), we offer custom o-rings made to ISO 3601-1 Class A (Precision Grade). While the stricter manufacturing and QC processes result in a higher cost, they deliver unmatched reliability and longevity for your systems.
O-Ring Advantages & Disadvantages
O-rings are widely used in various dynamic and static sealing applications due to their low manufacturing cost and ease of use.
Advantages: O-rings feature a simple and reliable structure with compact dimensions that enable space-efficient installation. They provide consistent self-sealing performance without requiring periodic maintenance adjustments and can achieve zero leakage in static applications. Their wide selection of material compounds ensures good compatibility with various media, while their strong environmental adaptability makes them suitable for diverse operating conditions, offering versatile and cost-effective sealing solutions.
Disadvantages: O-rings have high breakout friction resistance when used as compression seals. They are also prone to issues such as cutting, twisting, extrusion, or rupture if improperly installed or used. Achieving zero leakage is difficult in dynamic sealing applications, and leakage can only be controlled within specified permissible limits. In some cases, protective backup rings or wiper rings may be necessary, and for pneumatic or hydraulic sealing, auxiliary lubrication systems might be required.
Special-Section O-Rings
O-rings are prone to damage, such as extrusion and spiral twisting during installation and use, leading to seal failure. To address this, special-section o-ring designs have been developed. These designs enhance structural stability and improve sealing performance under demanding conditions.
Due to difficulties in mould processing and high manufacturing costs, special-section o-rings are currently only used in certain specific industries. Savvy has the expertise in mould design and production to offer these special-section o-rings at a minimal tooling cost and competitive price, ensuring superior quality and precision for your specific application.
- The square section offers high-pressure resistance, vibration resistance, and good stability, but has high friction and is mainly used for static seals.
- The D-ring, with its flat sealing surface, is often used in applications where a specific mating surface geometry is required, such as in hydraulic flanges or static face seals.
- The triangular ring provides a line contact or a well-defined sealing surface, making it suitable for static seals in confined spaces or as a wiper ring.
- The T-section, equipped with two spiral retaining rings on both sides, provides particularly excellent resistance to twisting and extrusion.
- The heart-shaped section is a seal for light-duty, low-pressure, small rotating shafts.
- The X-section has lower friction than the square section and offers good resistance to extrusion and twisting.
- The Angle-O section, equivalent to three O-rings in series, is characterised by high-pressure extrusion resistance.
- The polygonal ring, typically with a hexagonal or octagonal cross-section, offers multiple sealing lines and can be effective in high-pressure static applications, sometimes serving as a cost-effective alternative to metal seals.
