J518/1_201301 Hydraulic Flanged Tube, Pipe, and Hose Connections, 4-Screw Flange Connection Part 1: 3.5 MPa to 35 MPa (Code 61)

Numerous changes have occurred in the industry since this standard was last updated. ISO 6162 was adopted and it added metric bolts. Over the years, SAE J518 has gone from hard inch to inch (metric referenced) and with this revision metric. The metric dimensions needed to be fine-tuned to eliminate conversion errors. The metric numbers in the SAE standard were reference numbers in the old document that moved the acceptance range by as much as 30% of the tolerance when compared to the inch numbers. At the same time, the standard is to be harmonized with the current ISO 6162-1 with the intent of incorporating the changes into an ISO 6162-1 proposed revision. To help eliminate confusion and improve the connection, a minimum of class 10.9 metric (SAE grade 8 or better) screws are now required. This revision corrects the numbers, corrects problems with the O-ring groove, increases the radius between the d₈ and d₉ flange head dimension, uses a common clearance hole for inch and metric bolts, adds burst pressure and other requirements, changes & recommends a washer, and numerous other changes from the 1993 revision. The pad spacing has also been changed to recognize that it could be a cavity as well as a raised or flat surface.