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SAE J518-3-2021: Two-Screw Flange Clamps for Low-Pressure Hydraulic Connections
This standard provides the general and dimensional specifications for two-screw flange clamps intended for low-pressure applications with SAE J518-1 (Code 61) four-screw flange connections. The clamps are also compatible with ISO 6162-1 port connections and flange heads.
Standard Specifications and Engineering Insights
🛠️ Design Insight: The working pressure of an assembly is limited by the lowest rated component. Always verify the pressure rating of clamps, screws, washers, and O-rings to ensure system safety.
The following table summarizes key material and dimensional specifications from the standard.
| Component | Specification |
|---|---|
| Flange Clamp Material | Ferrous; min yield 415 MPa; min elongation 3% |
| Screws (Metric) | Property class 10.9 per ISO 898-1; inch screws not allowed for new designs |
| Washers | ISO 7089 Type A, HV300 or ASME B18.22.1 Type B narrow (HV300) |
| O-Rings | ISO 3601-1 size code, tolerance class A; grade N per ISO 3601-3 |
| Corrosion Protection | 96h coating/144h base metal salt spray (ISO 9227/ASTM B117); no cadmium or hexavalent chromate |
All dimensions have tolerances of ±0.4 mm unless otherwise noted. A maximum draft angle of 6 degrees from surface B is allowed. For complete port and flange head dimensions, refer to SAE J518-1.
Frequently Asked Questions
⚠️ Can two-screw clamps be used with Code 61 ports? Yes, they are designed for use with SAE J518-1 (Code 61) connections, but only in low-pressure applications.
🔍 What screws are permitted for new designs? Only metric screws of property class 10.9 or higher are allowed for new designs. Inch screws should not be used in new projects.
What is the maximum working pressure? The assembly pressure must not exceed the lowest rated component pressure.
What quality criteria do O-rings need to meet? O-rings must conform to grade N acceptance criteria in ISO 3601-3.
