I would like to ask for advice on the inspection of Class C and D welds.
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This post was last edited by deus on 2010-9-8 15:29. Under what circumstances do Class C and D welds require 100% non-destructive testing? Today I came into contact with a set of equipment that is exposed to hydrogen and wet H2S. The design pressure is 7Mpa and the design temperature is 280°C. One of the technical requirements states that "C and D class welded joints with an inner diameter greater than 200mm shall be ultrasonic tested according to JB/T4730-2005 and qualified for Level I." Which standard is the basis and source of this statement? Please give me some advice, thanks! ———————————————————————————— I'm very sorry, it's an ultrasonic test, not a radiographic test ~ I was negligent.~
So are Class A and B welds also qualified as Class I? If it is qualified at level II, it may be written incorrectly. It may be qualified at level I by magnetic particle testing.
I guess only if the client asks for it
The technical requirements are generally written in accordance with JB/T4730.2(.3.4.5)-2005 for testing, so that you can know what method to use for testing. Class C and D welds generally require surface testing, and ultrasonic testing is more stringent. Radiographic testing may not be possible. How to attach the patch? Contact the design institute to see if there is a clerical error.
Contact the owner and designer to see if there is a clerical error. Fillet welding cannot be used to attach patches
The national standard stipulates that designers can improve testing standards. The requirement for 100% ultrasonic welds for CD type welds raises the requirements. 4710.2 ultrasonic testing has requirements for the inner diameter of the pipe, and it can only be done if it is larger than the diameter.
Generally, it is magnetic particle and penetrant testing, and the qualification level is Level I.
According to page 23 of the "Fixed Pressure Capacity Safety Technical Supervision Regulations" for Class C and D welded joints, corner joints and T-shaped joints can be subjected to radiographic and ultrasonic testing. There are also other standards that state that Class D welds can be subjected to ultrasonic testing, but in fact each manufacturer only performs surface testing. It’s really hard to say whether it will work or not.