ABSTRACT
When pressures to be sealed rose to higher levels, and welding was used as the joining technique in constructing pressure vessels, the forged-steel flange became popular. To reduce the bolt area required to compress a gasket, its area was reduced and the ring gasket, lying fully within the bolt circle of a bolted
flanged connection, became the industry standard (see Fig. 1). The full-face gasket did not disappear, however. It has been used for a number of low-pressure applications, also for noncircular flanges, and certainly for flanges of cast-iron valves. For such cases, the accepted practice in industry has been to remove the raised face from a standard forged-steel flange and use this modified flange with a full-face gasket as mating flange on cast-iron valves.
