SAE Flange: O-Ring Size Selection

In SAE flange connections, O-rings play a crucial role in ensuring a secure and leak-free seal, especially in high-pressure hydraulic systems. Selecting the correct O-ring size is essential for maintaining system efficiency, preventing leaks, and extending the service life of hydraulic components. This article explores the key factors in choosing the right O-ring size for SAE flanges, standard sizing guidelines, and best practices for installation.
1. The Importance of O-Ring Selection in SAE Flanges
O-rings serve as sealing elements between the flange surface and mating component, preventing hydraulic fluid leakage. The correct O-ring size ensures:
Optimal sealing performance under high pressure.
Reduced wear and deformation, enhancing durability.
Compatibility with hydraulic fluids, preventing material degradation.
Choosing the wrong O-ring size may lead to fluid leaks, premature wear, and system inefficiency, increasing maintenance costs and downtime.
2. Standard O-Ring Sizes for SAE Flanges
SAE flange O-rings are standardized according to SAE J518 and ISO 6162, ensuring compatibility with Code 61 (standard pressure) and Code 62 (high pressure) SAE flanges.
Common O-Ring Size Chart for SAE Flanges (AS568 Standard)
SAE Flange Size
O-Ring Dash Number (AS568)
Inside Diameter (ID) (inch/mm)
Cross-Section (CS) (inch/mm)
1/2”
-908
0.737” (18.72 mm)
0.103” (2.62 mm)
3/4”
-912
0.978” (24.84 mm)
0.103” (2.62 mm)
1”
-916
1.225” (31.12 mm)
0.103” (2.62 mm)
1-1/4”
-919
1.487” (37.77 mm)
0.103” (2.62 mm)
1-1/2”
-922
1.737” (44.12 mm)
0.103” (2.62 mm)
2”
-926
2.225” (56.52 mm)
0.139” (3.53 mm)
2-1/2”
-932
2.737” (69.55 mm)
0.139” (3.53 mm)
3”
-936
3.237” (82.23 mm)
0.139” (3.53 mm)
4”
-944
4.237” (107.65 mm)
0.139” (3.53 mm)
For high-pressure Code 62 SAE flanges, O-ring sizes may differ slightly due to increased sealing requirements.
3. Factors to Consider When Choosing an O-Ring for SAE Flanges
1. Material Compatibility
O-rings are available in various materials, including:
Nitrile (NBR): Excellent resistance to hydraulic oils, commonly used in industrial applications.
Fluorocarbon (FKM/Viton®): High-temperature and chemical-resistant, ideal for demanding environments.
EPDM: Suitable for water-based fluids but not oil-based hydraulic systems.
2. Operating Pressure and Temperature
Standard pressure SAE Code 61 flanges typically use standard O-rings.
High-pressure SAE Code 62 flanges require reinforced O-rings with higher compression resistance.
3. Installation and Groove Fit
• Ensure the O-ring groove is clean and free of debris.
• Avoid overstretching the O-ring during installation to maintain proper sealing.
• Apply lubrication (compatible with O-ring material) to reduce friction and prevent damage.
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4. Reliable SAE Flange O-Rings from XFJTS
XFJTS offers a complete range of SAE flange O-rings, manufactured to SAE J518 and ISO 6162 standards for superior sealing performance. Our O-rings are designed to withstand high pressure, extreme temperatures, and hydraulic fluids, ensuring long-term reliability in industrial and hydraulic applications.
For more details, visit jetefittings.com.
5. Conclusion
Selecting the correct O-ring size and material is essential for maintaining a leak-free SAE flange connection. By following SAE J518 and AS568 standards, engineers can ensure compatibility, prevent system failures, and extend the lifespan of hydraulic components.
For high-quality SAE flange seals and fittings, trust XFJTS to provide precision-engineered solutions for your hydraulic system needs.



Post time: Feb-12-2025

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