Can holes be made in the welds of pressure vessels?
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This post was last posted by tonghui2008455 on 2009-10-12 10:22 Editor: The company's construction workers have always tried to avoid openings in the welds when typesetting. If they encounter customers who are not very demanding, they can just take pictures at the openings and then open the holes. Now there are a batch of Korean people doing the work. I don't know what the owners' requirements are. Some drawings (Class I, 20% flaw detection) require holes in the welds to facilitate typesetting, and there are external reinforcing rings at the pipe mouth. If the customer's requirements are not taken into account, this should be allowed based on regulations, right?
Circumferential welds are acceptable (100% RT inspection must be done within twice the diameter of the opening), but it is best not to open holes in longitudinal welds.
Regarding whether holes can be opened on the weld of the pressure vessel, it mainly depends on whether the technical requirements of the general drawing are designed according to Chinese standards; if it is designed according to GB150 and capacity regulations, the nozzle can be opened on the weld but attention must be paid (100% RT inspection is required within twice the diameter of the opening).
Yes, but flaw detection is required, and because heat superposition affects performance, try to avoid it.
This post was ended by Wise Man Bu Yu 2009-10-17 10:50 It is possible to edit the circumferential weld because it is determined by the width of the sheet, but it is necessary to avoid the circumferential seam through typesetting as much as possible. Openings on the longitudinal seams are generally not allowed. When assembling, you need to consider avoiding longitudinal seams, and it is very easy.
Personally, I think whether or not we can open holes in the weld mainly depends on the grade of the pressure vessel. High-grade pressure vessels are very dangerous even if they are fully inspected. GB150 is basically applied in accordance with the American ASME standard, so it is best to avoid opening holes in the weld.
Weld openings are not allowed, but they should be avoided if possible. The main reason is that during the welding process, welding will appear on the weld, and the energy will be superimposed. I think the weld will be equivalent to the effect of one repair. In the standard, it is generally required that the distance between adjacent welds is not less than 100. However, if there are difficulties in typesetting, 100% flaw detection must be carried out within 1.5 times the diameter of the weld opening.
Judging from the tone and words of the poster, I suggest that the poster should re-type the layout and put the connecting hole on the weld just for the convenience of typesetting. I think it is wrong. What can be avoided should be avoided as much as possible. GB150 does not impose a mandatory provision, which does not mean that it can be avoided but not avoided.
ASME allows openings in welds, but additional inspections are required. GB150 does not say whether this is allowed or not. Logically speaking, there is no problem. The welds near the openings must be inspected.
There is no prohibition in GB150 and "Content Regulations", but it should be avoided as much as possible through layout. It is indeed unavoidable to conduct flaw detection as required.