Inspection of circumferential seams in heat exchanger tube sheets and shell sections
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As shown in GB151, the welds between the tube sheet and shell sections, which feature this stress groove structure, are classified as Category B. How should such welds be inspected? Is flaw detection needed?
Inspection is required; RT should be used where possible, and UT should be used in cases where RT is not feasible
What was said on the 2nd floor is right! Inspection is required within the tolerance range. PT can be performed if it is not within the tolerance specifications
TOFD and UT that can record data are both acceptable; if a UT that cannot record data is used, one of the first two options must be added as a local feature
It is clearly classified as a Class B weld in the specifications; it seems that testing is necessary. The issue is merely the method of testing – RT probably won’t work, as it’s difficult to apply the inspection film properly
In accordance with clause 4.6.4 of GB/T151-2014, for the circumferential weld joints of the shell side cylinder in fixed-end plate heat exchangers where non-destructive testing is not possible, TIG welding should be used for the root pass, or gussets that are in close contact with the base metal should be used along the entire length of the weld root; the weld joint coefficient in such cases is 0.6.