Regarding the issue of extended non-destructive testing after weld repair
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According to clause 4.2.5.2.(2) on page 38 of TSG21-2016, for welded joints that have undergone partial non-destructive testing, if any defects exceeding the allowable limits are found in the areas that were tested, supplementary testing covering at least 250 mm each in the areas extending from both ends of those tested areas is required. If unacceptable defects still exist, then a full non-destructive testing of the entire welded joint must be carried out； ”Unlike GB/T150-2011, TSG21 requires extension outward from both ends of the inspected area, while GB/T150-2011 requires extension outward from both ends of the defect. Which standard should be followed?
The quality of the non-destructive testing section of the fixed-volume gauge is rather poor; this can be seen from the subsequent revisions. It’s better to follow GB150 instead
The standards are not strict enough; in other words, if a film is deemed unqualified, two additional films are taken at each end of that unqualified film, meaning a total of two additional films are taken； So, if two films need to be taken on the first try and one of them is not satisfactory, how can two more films be taken? Similarly, if three images are taken at once and only the one in the middle is unsatisfactory, how should additional shots be taken? ? ? :o:L
According to TSG21, one is a mandatory standard and the other is a recommended standard
Extended inspection is carried out on the areas that have not been inspected, up to 100%. Ten images have been taken, numbered from 1 to 10; if any of these images are found to be defective, inspection is conducted at positions -1 and 11. If defects are detected there as well, then the entire weld seam is inspected. Inspection at 20% level is only permitted if the manufacturer can guarantee that the quality of the entire weld seam is satisfactory; if the manufacturer cannot ensure the welding quality, then 100% inspection is required
150 extending outward from both ends of the defect means that, in some cases, after repair, it may not be necessary to perform further testing
What are the two ends of a defect? If 10 sheets are used and sheets 5 and 6 are defective, how many more sheets should be added? How to expand?
The last edit to this post was made by Forgetting = Forgetting on 2019-8-22 at 09:43. The edge of the valid inspection area on the defective flaw detection film indicates that the location of the defect extends to both sides within 150 units
1. “GB/T150-2011 involves extending from both ends of the defect” – this assumes that the length and location of the defect are already known. If the length and location are already known, then why is it necessary to extend the detection area? 2. \"...additional testing of at least 250 mm each at the extensions at both ends of the tested area is required...\" This refers to situations where defects have been detected but their length has not yet been determined; in such cases, it is necessary to extend the testing range in order to determine the exact length and location of the defects. Which one do you think is reasonable?
150 extending outward from both ends of the defect means that, in some cases, after repair, it may not be necessary to conduct further testing. Can you give an example?
What is the difference between these 2? It seems to convey the same meaning