For heat exchangers classified as Category II, if seamless steel tubes are used for the shell, has their mechanical properties been retested?
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For shell-and-tube heat exchangers classified as Category II, in accordance with HG20581-2011, if seamless steel tubes are used for the shell, their mechanical properties must be retested, and a hydrostatic test must be carried out at the pressure specified for hydraulic testing. Is this the practice followed by everyone? If the design specifications column in the overall diagram only lists GB150 and GB151 without mentioning this standard number, can this requirement be ignored?
It’s best to follow this. Anyway, in our company, whenever we encounter something like this, retesting is basically required.
GB150 and GB151 are the harmonized standards for TSG21-2016; if these two standards can meet all the requirements of the design, there is no need to refer to the HG series of standards, nor is it necessary to comply with the provisions in those standards.
If it is not specified in the design documents, it is not necessary to carry out this step, as long as the quality is maintained. However, since we are ultimately responsible for the product quality, it is still possible to do it
This is generally not mentioned, but it’s best for one’s own sake, and of course that’s ideal.