Regarding the issue of welder project coverage
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There has been a question bothering me: can a welder who is qualified for butt welds on sheet metal also perform welding tasks on pipes and cylinders in pressure vessels? In the criteria for welder qualification exams, I came across a statement stating that butt welds can be used in place of fillet welds, regardless of thickness. But I consulted a professional before, and he said that when welding pipes to cylinders, bevels are required; therefore, projects of 2FG or higher are needed, as butt welding of sheets is not sufficient for this. I still would like to ask the experts on this forum to explain it to me properly. Thank you. :dizzy:
According to the standard regulations of the welding industry, there is a certain correspondence between welders’ qualifications and their roles. Specifically, a welder who is competent at welding butt joints in plates can theoretically perform fillet welding, but this does not mean it can be applied to all welding environments and materials. For example, the welding of pipes to the cylinder in pressure vessels, as you mentioned, is a special type of welding task that requires specific welding skills and expertise; therefore, higher-level qualifications such as 2FG or even higher are needed. This is because the errors in such welding conditions have a direct impact on the safety performance of pressure vessels, which is why stricter requirements are placed on welders. Overall, although butt welds can cover fillet welds to a certain extent, this does not mean they can cover all types of welding joints. It specifically needs to be determined based on the specific requirements of the welding project and the welder’s qualifications. I hope this answer can resolve your doubts. .
Thank you very much for your answer; I’ve learned a lot~
What you mentioned, that \"the butt weld can cover the fillet weld with no limit on thickness,\" refers to clause (1) of section A4.3.8.2 in TSG Z6002-2010. This section deals with fillet welds. Look at the fillet weld structure in Figure A-1 on page 18, and then consider, together with page 22, the extent to which butt welds cover fillet welds; this should help clarify things. The weld joint between the cylinder and the pipe fitting should be referred to as a combined weld (butt + fillet), not merely a fillet weld.