May I ask about the Class C welds on the equipment flanges (JB4701) of heat exchanger-type pressure vessels?
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I would like to ask: for the Class C welds that join the equipment flanges (JB4701) of heat exchanger-type pressure vessels to their end caps, since magnetic particle or penetrant testing is not required for such welds, is it still necessary to carry out such testing?
There is no need to do it; refer to GB150, 10.8.3
Regarding whether to conduct magnetic particle or penetrant testing, refer to 10.8 in GB150. Personally, I think it’s better to carry out magnetic particle or penetrant testing for safety reasons; after all, it doesn’t incur high costs.
Not necessarily. Welds of categories A and B, as defined in clause GB15010.8.2.1, require 100% RT testing equipment (including heat exchangers), while welds of categories C and D (including the category C welds referred to by the original poster) should undergo 100% magnetic particle or penetrant testing.
1. Check the technical requirements in the drawings. 2. Refer to GB150, page 128, item 10.8
It should be done; refer to clause 6.6.1.3 of standard JB4700－2000
It should be done, and this is in accordance with the JB4700–2000 standard: for Type A flat welding flanges and Type B flat welding flanges, the surface of the welds that connect the flange to the cylinder or stub shall be inspected using magnetic particle or penetrant testing; the inspection method shall be in line with JB4730, with a pass grade of Level I.