ISO 6164 square flange standard specifies Material of flange clamps, flange heads, screws, o-rings.
ISO 6164 4 Flange clamps, which shall be of ferrous material with the following properties in the finished condition:
— minimum yield strength: 330 MPa;
— minimum elongation at fracture: 5 %.
ISO 6164 4 Flanged heads, which shall be of ferrous material with the following properties in the finished condition:
— minimum yield strength: 330 MPa;
— minimum elongation at fracture: 10 %.
ISO 6164 4 Screws. Unless otherwise specified, one of the following screw options shall be used:
a) hexagon head screws conforming to ISO 4017 of property class 10.9 (minimum) in accordance with ISO 898-1;
b) socket head screws conforming to ISO 4762 of property class 10.9 (minimum) in accordance with ISO 898-1.
ISO 6164 4 O-rings. Unless otherwise specified, the O-rings shall be made of NBR (nitrile) with a hardness of (90 ± 5) IRHD, measured in accordance with ISO 48, for use at the pressure and temperature requirements given in Clause 8 and for testing. The O-rings specified in Table B.1 shall conform to the dimensions given in ISO 3601-1 for the relevant size code. They shall also conform to 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. If the flange connection will be used at temperatures higher than specified in Clause 8, O-rings made of materials that meet the higher temperature requirements shall be used.
Unless otherwise specified, tolerances shall be in accordance with ISO 2768-m (medium)
