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This article details the hardness requirements for RX ring joint gaskets, essential for ensuring leak-tight seals in high-pressure flange connections.

Octagonal ring joint gaskets are high-integrity metallic seals used in oil and gas flanges. The primary standard governing their design, dimensions, and materials is ASME B16.20, which defines ring numbers, oval and octagonal cross-sections, hardness levels, and groove compatibility with ASME B16.5 and B16.47 flanges.

R-type oval ring joint gaskets are standard gaskets with an oval or octagonal cross-section used in conventional ring joint flanges, while RX-type gaskets are designed for high-pressure API flanges with a modified contour that enables a pressure-energized seal for improved performance.

A tanged metal graphite gasket works by using a metal core with serrated tangs that grip and compress a flexible graphite facing, allowing the graphite to conform tightly to flange surfaces and fill microscopic irregularities for a reliable seal under high temperatures and pressures.

Pure expanded graphite gaskets are generally suitable for steam applications due to their high heat tolerance and chemical resistance. They provide reliable sealing at elevated temperatures, though their performance can be limited by oxidation in oxygen-rich steam environments and potential long-term degradation above certain pressure and temperature thresholds.

Non-rounded spiral wound gaskets feature custom shapes to fit non-circular flange geometries, unlike standard round gaskets designed for circular flanges. Their construction allows for precise sealing on oval, rectangular, or irregular profiles, requiring tailored winding and centering methods to maintain uniform compression and leak resistance. This adapts the core spiral wound seal to applications where round gaskets cannot provide an adequate fit.