Questions regarding pipe flange standards
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I have a humble question for everyone: in the standards for steel pipe flanges, what are the differences between HG 20592-1997 (Forms and parameters of steel pipe flanges) and HG20595-1997 (Waisted butt-welded steel pipe flanges)? For example, I’m referring to a butt-welded flange; should the standard number be 20592 or 20595?
It should be written as HG20595-1997.
We often encounter this issue in actual production. In my opinion, as long as it is clear how to make the marking, any method is acceptable. HG20592-97 is a general standard; by specifying the flange code, it is possible to determine the corresponding smaller size. When providing standards, we always refer to HG20595-97.
You can use 20592 as well; 20595 is more intuitive, as it’s clear at a glance that it refers to a butt-welded flange. For 20592, it depends on the type of flange, so you need to specify whether it’s WN
It should be written as HG20592, with consistent labeling
In fact, the relationship between HG20592-97 and HG20595-97 is similar to that between a street and house numbers: HG20592-97 represents the name of the street, while HG20595-97 is one of the house numbers on that street. Those that fall under HG20592-97 are HG20593-97 to HG20614-97. This is what we refer to as the European system in the standards set by the Ministry of Chemical Industry; whereas HG20615-97 to HG20635-97 represent our American system. According to the provisions of HG20592-97, it should be uniformly marked as HG20592; for details, one can refer to this standard.
Pipe flanges are uniformly designated by the standard code HG 20592-97, which is a general standard. HG20595-97 is more specific. It can also be considered that HG 20592-97 is included in HG20595-97; either one can be used. I work in the field of pressure vessels, and personally I recommend using HG20595-97.
HG20592-97 is a general standard; HG20595-97 would be more appropriate to use.
HG20593-1997 Plate-type butt-welded steel pipe flanges; GB9114-2000 Threaded steel pipe flanges; GB9115-2000 Welded steel pipe flanges; GB9116-2000 Necked plate-type butt-welded steel pipe flanges; GB9119-2000 Plate-type butt-welded steel pipe flanges; GB9120-2000 Welded ring plate-type loose-flange steel pipe flanges; HG20594-1997 Necked plate-type butt-welded steel pipe flanges; HG20595-1997 Necked welded steel pipe flanges; HG20596-1997 Integral steel pipe flanges; HG21547-93 Steel plugs, gaskets, and 8-shaped blind plates for pipelines; JB81-94 Raised-face plate-type butt-welded steel pipe flanges; JB82.1-94 Raised-face welded steel pipe flanges; HG20597-1997 Socket-welded steel pipe flanges; SH3406-96 Petrochemical steel pipe flanges; JB4700-2000 Classification and technical requirements for pressure vessel flanges; JB4701-2000 Type A butt-welded flanges; JB4702-2000 Type B butt-welded flanges; JB4703-2000 Long-necked welded flanges; JB4721-94 Flanges with external covers on the sides; JB82.2-94 Concave-convex face welded steel pipe flanges; JB82.3-94 Grooved-face welded steel pipe flanges; HG21547-93 Steel plugs, gaskets, and 8-shaped blind plates for pipelines; JB83-94 Butt-welded ring plate-type loose-flange steel pipe flanges; JB84-94 Concave-convex face welded ring plate-type loose-flange steel pipe flanges; JB85-94 Flanged plate-type loose-flange steel pipe flanges; JB86.1-94 Raised-face steel pipe flange covers; JB86.2-94 Concave-convex face steel pipe flanges; HG20598-1997 Threaded steel pipe flanges; HG20599-1997 Welded ring loose-flange steel pipe flanges; HG20600-1997 Butt-welded ring loose-flange steel pipe flanges; HG20601-1997 Steel pipe flange covers; HG20602-1997 Stainless-steel-lined pipe flange covers; HG20603-1997 Technical requirements for steel pipe flanges; GB9118-2000 Welded ring necked loose-flange steel pipe flanges; GB9121-2000 Butt-welded ring plate-type loose-flange steel pipe flanges; GB9122-2000 Flanged ring plate-type loose-flange steel pipe flanges; GB9123-2000 Steel pipe flange covers; HG20616-1997 Necked plate-type butt-welded steel pipe flanges; HG20617-1997 Necked welded steel pipe flanges; HG20618-1997 Integral steel pipe flanges; HG20619-1997 Socket-welded steel pipe flanges; HG20620-1997 Threaded steel pipe flanges; HG20621-1997 Welded ring loose-flange steel pipe flanges; HG20622-1997 Steel pipe flange covers; HG20623-1997 Large-diameter steel pipe flanges; JB82.4-94 Ring-connected face welded steel pipe flanges; GB9117-2000 Necked socket-welded steel pipe flanges; JB81-94 Raised-face plate-type butt-welded steel pipe flanges; JB82.1-94 Raised-face welded steel pipe flanges; JB82.2-94 Concave-convex face welded steel pipe flanges; JB82.3-94 Grooved-face steel pipe flanges; JB82.4-94 Ring-connected face steel pipe flanges; JB83-94 Butt-welded ring plate-type loose-flange steel pipe flanges; JB84-94 Concave-convex face butt-plate type loose-flange steel pipe flanges; JB85-94 Flanged plate-type loose-flange steel pipe flanges; JB86.1-94 Raised-face steel pipe flange covers; JB86.2-94 Concave-convex face steel pipe flange covers; SH3406-96 Petrochemical steel pipe flanges
HG20592 specifies clearly that the flange standard should always be indicated as HG20592; for wafer-type butt-welded flanges, it should be written as HG20592 WN100-2.5
Personally, I think it’s better to use HG20592-1997, as this standard applies to all flanges; it’s sufficient to specify the type only. . . :) :)