The final ring seam of the heat exchanger shell cannot be recorded as an additional RT or TOFD local inspection problem for ultrasonic inspection
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Regarding the non-destructive testing of the final ring seam of the heat exchanger shell, the General Administration of Quality Supervision, Inspection and Quarantine has the following reply: I would like to ask the friends in the design department how they usually deal with such problems? Is the following solution possible? 1 Only 100% UT and surface inspection are performed, no local RT or TOFD inspection is performed, and the weld coefficient of the final girth weld is 0.6. 2 Use GBT 32563-2016 "Nondestructive Testing Ultrasonic Testing Phased Array Ultrasonic Testing Method" for testing, and submit it to the General Administration of Quality Supervision, Inspection and Quarantine for approval.
Option 3: Design the welding joint in the form of b) or c) in the attached figure. The welding joint is classified as Category C. From the perspective of standard specifications, RT does not need to be done. However, the form a) in the attached drawing is beneficial in terms of stress concentration and penetration of the weld root. Because RT cannot be used, a worse structural form can only be used. Is there something wrong with the guidance of the standard specification?
Asking them this kind of question might as well ask the aunt on the roadside. Using B and C type joints is not necessarily the worst. If this type of joint is used, I believe the working conditions will not be very bad. In addition, you can do a stress analysis to determine whether it is necessary to design a butt weld.
Asking them this kind of question might as well ask the aunt on the roadside. Using B and C type joints is not necessarily the worst. If this type of joint is used, I believe the working conditions will not be very bad. In addition, you can do a stress analysis to determine whether it is necessary to design a butt weld.
Who do you mean by "they"? :D The inspection by the Special Inspection Institute is based on standard regulations and design documents. Here I want to discuss how to conduct non-destructive testing of the final circumferential seam of the heat exchanger shell to meet the requirements of standard regulations when RT and TOFD testing is not possible.
This post was finally edited by Pinocchio on 2018-1-19 14:05, a reply from the General Administration of Quality Supervision, Inspection and Quarantine, requesting a design to deal with such problems. But will the design institute have such a problem?: When designing, we don’t know where the final girth weld will be. Is it possible to perform RT or TOFD inspection? This is an issue that the manufacturing unit needs to consider.
Suggested option 3, the first two are not impossible, but if the design institute, the owner, and the special inspection institute do not approve it, you will have to go through the formalities. If option 3 can be used structurally, this is the best and no one will suffer.
Agree with you. 1. For option 3, does GB151 Appendix I Figure 1.1 b) belong to Category C welds? 2. Does adopting option 1 violate the requirements of the standard specification? GB151-2014 §4.6.4 Under what circumstances can it be used?
1. Belongs to Category C welds 2. Feasible. In fact, many companies do this. Stainless steel equipment cannot be mounted for RT inspection due to structural reasons. Argon arc welding is used as the base and 100% PT inspection is performed.
Regarding option 1, our inspector from the Special Inspection Institute does not approve it. They understand that the requirements of the compliance regulations are the minimum requirements, and the AQSIQ's response is to require the design to solve this problem and meet the requirements of the compliance regulations. According to the regulations, Class B welds require at least 20% RT or TOFD inspection. How to convince the Special Prosecution Office?
No matter which method you use, it is already higher than the capacity requirements.