Thick flat cover with perforated welded small tube structural format
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In equipment design, it is common to encounter structural configurations where thin pipes need to be welded through openings in thick flat covers, with full penetration required. This is especially true in composite plate structures, where the interior consists of stainless steel while the exterior is made of carbon steel. Since the pipes are thin, weld overlay is not an option; how then can full penetration be achieved? Please refer to the attached drawings for details. Thank you
Using the structure in your diagram will meet the requirements. Full penetration does not mean full penetration of the entire cross-section.
Thank you. I searched online and found two opinions: one is that full penetration and cross-sectional penetration mean the same thing, while the other is that full penetration simply means that the thickness of the weld metal is equal to the thickness of the base material; everyone agrees on the concept of cross-sectional full penetration. I tend to agree with the second view. What’s your opinion?
Thank you. I searched online and found two opinions: one is that full penetration and cross-sectional penetration mean the same thing, while the other is that full penetration simply means that the thickness of the weld metal is equal to the thickness of the base material; everyone agrees on the concept of cross-sectional full penetration. I tend to agree with the second view. What’s your opinion?
Thank you. I searched online and found two opinions: one is that full penetration and cross-sectional penetration mean the same thing, while the other is that full penetration simply means that the thickness of the weld metal is equal to the thickness of the base material; everyone agrees on the concept of cross-sectional full penetration. I tend to agree with the second view. What’s your opinion?
This structure only requires that the groove depth be ≥ the wall thickness of the pipe, and the weld angle height be ≥ 6； This is how we all weld ；
Okay, thank you. I also want to understand the difference between full penetration and full cross-sectional penetration, hehe
In my personal understanding, full penetration here refers to the condition where the entire groove surface as well as its root are properly welded together, with no defects such as slag inclusions or lack of fusion that exceed the specified requirements, and no underpenetration at the root； (Such as the welding of heat exchange tubes, the welding of various instrument connections on flange covers, etc.) Full-thickness penetration means that the entire cross-section is welded through, without any defects such as slag inclusions or lack of fusion that exceed the specified requirements. (Flat plate butt joints / Pipe and plate corner joints – such as single-sided full-thickness penetration achieved through TIG welding as a root pass, or full-thickness penetration achieved through welding on both the inner and outer sides.) This is my personal opinion; please let me know if you have different views! ! ! !
Agree with the view from floor 6. It is impossible to achieve full-thickness welding at the joint where a flat cover meets a small tube.
Thank you for your reply; I fully agree with your views as well. I contacted the relevant inspection officers at the Special Inspection Agency yesterday, and they were unable to provide any insights on this matter. Their opinions are basically the same as yours. I was wondering if there are any official statements on this topic? There is certainly no disagreement regarding full penetration across the entire cross-section; the key point is indeed full penetration. In section 3.2.2.2 on page P21 of the standards, it is specified that components such as pipe flanges should have a full-penetration structure. I wonder if there is any official clarification or explanation regarding this structure Thank you