Kaxite R-oval ring joint gasket is a solid metal sealing ring CNC-machined from forging to ASME B16.20, fitting ASME B16.5, ASME B16.47 Series A and API 605 flanges from Class 150 to Class 2500. The oval cross-section uses a rounded line-contact profile rather than the 23° face of the octagonal ring, which makes it the correct choice when the flange groove was cut to the original oval specification or when the joint runs at steady pressure and temperature without thermal cycling. On modern flanges machined to accept both profiles, R-oval and R-octagonal are interchangeable, so the decision comes down to groove history and service condition rather than bolt load.
Size range. R-oval rings follow the ASME B16.20 R-number table from R11 upward. Nominal size, bore and OD are fixed by the R number, so a replacement ring matches the flange without re-measuring.
Oval cross-section. The rounded profile seats on a line contact inside the groove. It tolerates slight groove wear and misalignment, but is less forgiving than the octagonal face under pressure cycling.
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| Dimension | Tolerance | Inspection method |
|---|---|---|
| Width of ring | ±0.20 mm | Calipers, three positions per ring |
| Height of ring | ±0.40 mm | Height gauge against the ASME B16.20 R-number table |
| Outside diameter | +0.00 / -0.15 mm | Outside micrometer |
| Bore (inside diameter) | ±0.20 mm | Inside micrometer |
| Pitch diameter | ±0.18 mm | Derived from OD and bore, cross-checked on surface plate |
| Sealing face flatness | ≤ 0.05 mm | Surface plate and dial gauge |
| Surface condition | Free of cracks, pits, tool marks and rust | Visual, 100% inspection |
| Hardness | Per material specification | Portable hardness tester, batch record |
Note that the R-oval profile has no 23° face angle — that parameter belongs to the octagonal ring only. If your inspection sheet was written for an octagonal ring, remove the angle line before comparing. Ring hardness stays below the flange groove hardness; if the ring is harder than the groove, the groove deforms first and the joint leaks. Dimensional and hardness records travel with every batch.
Soft iron (90 HB), low carbon steel (120 HB). Default grades on Class 150–600 carbon steel flanges in refinery, water and non-corrosive hydrocarbon service.
SS304, SS304L, SS316, SS316L, SS321, SS347, SS410, 310, 316Ti, 3CR12, duplex, 160–170 HB. SS304 and SS316 are the everyday stainless grades; SS347 suits high-temperature cycling; SS410 gives mild wear resistance for slurry-exposed seats.
Monel 400, Nickel 200, Inconel 600, Inconel 625, Inconel X-750, Incoloy 800, Incoloy 825, 150 HB typical. Sour service follows NACE MR0175 / ISO 15156, and the final grade depends on H2S partial pressure, chloride content and temperature. Send the media data and Kaxite will return a matching grade.
Hastelloy B2, Hastelloy C276, titanium, zirconium, copper, and PTFE (inner rings only — never as the R-oval sealing body). For seawater, strong acids, high-purity processes and other exotic media.
The R-oval profile covers the same flange range as R-octagonal. For the higher-pressure wellhead families, see the RX ring joint gasket (API 6B, 5,000 PSI) and BX ring joint gasket (API 6BX, up to 20,000 PSI) pages, or the ring joint gaskets parent page for the complete family.
Kaxite Sealing machines R-oval ring joint gaskets in Ningbo, Zhejiang, on the same CNC line that produces R-octagonal, RX, BX and lens rings, so a mixed project package can ship from one facility with one set of certificates. Standard sizes follow the ASME B16.20 R-number table; non-standard groove dimensions and special alloy rings are quoted from drawings. Free samples are available for qualified projects, with the mill certificate attached. Factory visits and video audits are welcome by appointment; ISO 9001 certificate details are available on request. For non-RTJ soft gasket alternatives on the same project, compare the spiral wound gasket range.
Request an R-oval ring joint gasket quote
Tell us flange size, pressure class, R-number, material grade and working media. Free samples, dimensional records and mill certificates available for qualified projects.
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No. 432 Zhenhai Middle Road, Luotuo Street, Zhenhai District, Ningbo City, Zhejiang China
