HG standard flanges paired with SH standard pipes
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I checked, and the outer diameter of the pipes specified in SH/T 3405-2012 is different from the wall thickness of the pipes specified in HG/T 20553-2011. So, if I choose the pipe series SH/T 3405, can I use flanges from HG/T 20592–20635-2009?
The pipe series of SH/T3405 can be paired with flanges from the American Standard Class system, namely HG20592～20635－2009.
It is best to use pipes with uniform specifications and standards; detailed descriptions should be provided in the design notes of the drawings!
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Thank you. I originally thought that differences in wall thickness could be a problem; for example, in HG/T20615, the wall thickness of the flange for DN300 class150 sch40 is 10.2, while in SH/T3405, the wall thickness of the pipe for DN300 sch40 is 10.31. These two values are different. After checking, I found that the corresponding wall thickness in HG/T20553 is 10.0. It turns out that even under standards from the same series, there are still differences in wall thickness
Please explain in detail why it is unqualified
This difference is due to the large number of domestic standards. In the past, these standards were based on American standards, with values being adjusted accordingly; now, they are generally aligned with American standards. In other words, for DN300/12”, the wall thickness corresponding to SCH40 is 10.31 mm
Generally speaking, it is best for steel pipe standards and fitting standards to belong to separate systems. For example, GB/T5310 pairs well with GB/T9119–9125; HG/T20533 pairs well with HG/T20592–20635; and SH/T3405 pairs well with SH/T3406. These pairing methods are generally acceptable. However, standards in China are rather chaotic – there are various industry standards. Even though there are many such standards, they mostly follow two systems: the European system and the American system. Only SH/T and JB/T standards tend to be more straightforward, while standards like GB and HG incorporate elements from both systems. The dimensions in these standards are generally similar. Returning to the original question, what the poster asked is feasible – SH/T3405 can be paired with flanges from series such as HG/T20616 and 20617. A slight difference in pipe wall thickness is not a problem, as both American and Chinese standards, as well as German standards, allow for a tolerance of -102.5% in terms of wall thickness; as long as it remains within this range, it’s fine