How is the wall thickness selected in GB/T12459-2017?
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The new version of the GB/T12459-2017 standard has been released, and it will come into effect in September. The wall thickness classification table for steel pipes specified in the 2005 version has been removed; so, how should the wall thickness of these pipe fittings be determined in the new version?
The steel pipe wall thickness classification table in the 2005 version is based on sources elsewhere; see the appendix for reference. . .
This post was last edited by north_star on 2017-5-25 11:26. Is there any standard corresponding to that wall thickness classification table? There is a formula for determining the Sch number, but it always needs to be rounded to a standard value. Is there a corresponding standard for this value? Oh, I saw it after the 2005 version; it is taken from ASME B36.10M and ASME B36.19M. So, when choosing the wall thickness later on, do I still need to refer to these two ASME standards? These two sets of standards are also constantly being updated. They were both issued in 2015, and they are in a foreign language; moreover, the updates in China do not keep up with those abroad. Look at how things have turned out – it’s so exhausting! In Part 3 of GB/T13401-2017, under item c), it is stated that for the nominal wall thickness, one should refer to 4.2.2 of GB/T12459-2017; however, the content of 4.2.2 in GB/T12459-2017 is quite abstract and difficult to understand. According to 4.2.2 of GB/T12459-2017, I understand that there is no fixed standard value thereafter; as long as the manufacturer provides a pressure test to show the maximum pressure that the product can withstand, one can choose it based on that information. What does it mean to determine wall thickness values through verification pressure tests? The wall thickness must be determined first, right? How can tests be carried out without having the product ready? Or do customers order custom ones based on calculation or analysis needs? What is all this? Pardon my ignorance!
This 2017 version of the standard does not clarify the issues related to the labeling of fittings; it is vague, and I spent a long time searching online without finding any answers.
Same question: in the detail table, when specifying the wall thickness grade, should we write SCHxx, or should we directly indicate the specific wall thickness value?
The markings on fittings should be consistent with those on the pipes. The wall thickness of pipes is determined according to Sch, and the wall thickness of fittings is also indicated as Sch. If the pipe wall thickness is not based on the Sch series, then the fitting’s wall thickness is indicated directly (same as that of the pipe).
This 2017 version of the standard is really terrible. . . .
It’s even worse than the old 2005 standard