Surface inspection issues
Thread Content
Fixed tube sheet heat exchanger, with the tube sheet serving as a flange, and stubs on the tube box. The specifications state that surface MT testing is to be carried out on the Class C joints between the equipment flanges and the tube sections; it is certainly the intention of the design to perform surface testing on the Class C joints between the shell flanges and the short sections. People are wondering whether MT testing is required for the Class C joints between the tube sheet and the shell when it is written this way in the drawings
Based on the poster’s description, it is impossible to determine what tests should be performed on the tube sheet and shell; the requirements can only be ascertained by reviewing the drawings
Under normal circumstances, this position is also MT
There are requirements in NB/T47020
The welds between the tube sheet and the cylinder face much more severe stress conditions than those at the tube box flanges; therefore, inspecting them is of primary importance
Why are no testing requirements specified for this in GB151, whereas equipment flange standards do require tests for such joints?
The common practice in China’s industry is to choose the higher option rather than the lower one, so that’s what should be done
The domestic standard is that as long as a requirement is specified in any book, it must be implemented in the drawings; the standard must be followed without exception. If the standard isn’t reflected in the drawings, then it must be carried out in accordance with the standard, or changes must be agreed upon through negotiation. If there’s no paper form, it must be done anyway.