SAE J518-2 standard sepcifies materials for Flange Clamps, screws, washer, o-ring seals as follows:
Shall be made from a ferrous material with the following properties:
− Min yield strength: 415 MPa
− Min elongation at fracture 3%
Unless otherwise specified, use hexagon head screws or socket head screws of property class 10.9 (minimum), as specified in ISO 898-1, or equivalent inch (SAE grade 8 hex head cap screws or ASME 18.3 socket head cap screw of ASTM A574 material) screws. Inch screws shall not be used for new design.
The use of hardened washers is recommended. Washers, if used, shall conform to ISO 7089 Type A, Class 300HV and be sized for the corresponding screw except for the DN 32 (-20) type 2 (inch) size which shall conform to ASME 18.22.1 type B narrow (HV300). Plain washers conforming to ASME B18.22.1, type B narrow (HV300) series, may be substituted
when using Type 2 screws except for the DN 32 (-20) size. The ISO 7089 washer might cause interferences if used with the inch screw in the DN 32 (-20) size.
Connectors conforming to this International Standard use elastomeric seals. Unless otherwise specified, connectors are made and delivered with elastomeric seals for use within the specified working temperature range with petroleum base hydraulic fluids. The use of these connectors and elastomeric seals with other hydraulic fluids can result in a reduced
working temperature range or can render the connectors unsuitable for the application. Manufacturers may supply, upon request, connectors with elastomeric seals for use with hydraulic fluids other than petroleum base hydraulic fluids which meet the specified working temperature range of the connectors.
The O-rings in Tables 1A and 1B shall correspond to the size code, tolerance class A in ISO 3601-1 and shall meet or exceed the O-ring quality acceptance criteria for grade N of ISO 3601-3. Unless otherwise specified, the O-rings shall be of NBR (nitrile) with a hardness of 90 ± 5 IRHD measured in accordance with ISO 48.