Issue with the outer diameter of the welded end of DN700 large-diameter reinforced butt weld flanges, Series B
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Hello everyone, according to standard HG/T 20623 or ASME B16.47, for the large-diameter flange series B, DN700-Class300 flanges have an outer diameter of 716 at the welded end, while the outer diameter of ordinary steel pipes is 711. Won’t this cause misalignment during welding? How is this problem usually solved? (Is it possible to specify when placing an order that the welded end be made as 711?) ), this problem does not exist with the A-series flanges.
Tubes with flanges can be rolled by oneself, or tubes with an outer diameter of 716 can also be purchased
This post was last edited by lovepds on 2022-4-2 at 16:06. The inner diameter of the flange in Series B is the same as that of the steel pipe; the outer diameter of the welded end is larger than that of the steel pipe, and this can be addressed by creating bevels. It is possible to request that the inner and outer diameters at the flange’s welded end match those of the steel pipe at the time of manufacturing. If no such requirement is specified, it is still possible to handle the flange bevels during construction. When welding the flange to the steel pipe, their inner diameters are aligned, so welding is not a problem.
Thank you for your reply. I’ve discussed this with the supplier; it was stipulated that during procurement, the outer diameter and wall thickness of the flanged weld end should match those of the steel pipe. Thank you