Are openings allowed in the welds of pressure vessels?

Piercing the welds should not be allowed. The pressure vessel design codes also specify the required distance between openings and welds!

According to 10.8.2.2 of GB150: All weld joints contained within a circle with the center at the opening center and a radius of 1.5 times the opening diameter shall be subject to full radiographic or ultrasonic testing; the testing level shall be determined in accordance with the drawings.

Generally, it depends on what kind of equipment you have; for ordinary devices, 100% inspection is required after activation

Under normal circumstances, holes are not made near welds. When it is necessary to make such holes due to structural reasons, they can be created; however, as mentioned on the 3rd floor, 100% radiographic or ultrasonic testing must be conducted on the butt welds within a certain range around the hole.

It is possible; two aspects need to be considered. One is strength – the weld coefficient for the shell at the opening should be taken as that of the shell’s welds at that location (or 1 if the opening is not located at a weld). The other aspect is radiographic inspection: all welded joints within a circle centered on the opening’s center with a radius of 1.5 times the opening diameter must undergo radiographic or ultrasonic testing. The level of inspection shall be in accordance with the specifications provided in the drawings, and the area within the circle of radius equal to the opening diameter can be included in the scope of inspection

100% flaw detection of the welds is carried out over an area corresponding to 1.5 times the diameter of the opening; indeed, there are no regulations or standards prohibiting the creation of openings in the welds. For 100% non-destructive testing near the openings, attention should be paid to the required qualification level. Additionally, if there are reinforcement rings, the welds must also be smoothed out.

Try to avoid welds, but if it is not possible due to structural reasons, holes can be made. All weld joints within the circle centered on the opening center with a radius of 1.5 times the opening diameter shall undergo full radiographic or ultrasonic testing.

It is not mandatory; it is sufficient to perform expanded testing on the welds.

It’s best to avoid it under normal circumstances, but it’s not prohibited. If it actually forms on the weld, the inspection rate should be increased, and measures such as grinding to relieve some of the welding stress should be taken

It is generally recommended not to make holes at welds; if a hole must be made, then 100% radiographic or ultrasonic inspection should be carried out on the weld area within a circle with a diameter 1.5 times that of the hole, centered on the hole’s location.

Holes can be made, but this should be avoided as much as possible; after all, the welds intersecting with each other can lead to the accumulation of welding residual stresses, resulting in higher stress levels. Non-destructive testing shall be carried out in accordance with GB150.

There is no explicit prohibition on making holes; it’s sufficient to perform 100% flaw detection for those holes! But now, CNPC’s equipment does not allow any holes to be made in the welds! !

Yes, it is necessary to carry out additional testing in accordance with GB150, and 20% of the testing volume should be included in this

The standards do not impose a requirement prohibiting openings, but stress buildup can occur as a result of them, so it is best to avoid them. If openings must be made, 100% radiographic testing of the welds is required. Vibration aging is recommended to relieve stress after welding.

It is possible, but efforts should be made to avoid welds. When it is not feasible to do so due to structural constraints, two factors need to be taken into account: one is strength – the weld coefficient for the shell at the opening location should be used, which is 1 if the opening is not located at a weld; the other factor is radiographic inspection. All weld joints within a circle with a radius of 1.5 times the opening diameter, centered on the opening, must undergo radiographic or ultrasonic testing. The level of inspection shall be as specified in the drawings, and the area within that circular range can be included in the inspection scope

Under normal circumstances, holes are not made near welds. When it is necessary to make such holes due to structural reasons, they can be created; however, as mentioned on the 3rd floor, 100% radiographic or ultrasonic testing must be conducted on the butt welds within a certain range around the hole.

We have encountered this issue before: due to carelessness in the process layout, openings were placed on Class B welds. After consulting AI, we were given permission to do so. For welds that have undergone 100% radiographic inspection, there is no standard provision stating that openings are not allowed! So, let’s be a bit ambiguous!

Does anyone know what compensatory measures should be taken if holes are made in the welds? 100% flaw detection is merely a testing method. . . .

The pipe holes of pipe fittings should be avoided as much as possible from being located on the welds, and it should be prevented that the joint welds of the pipe fittings overlap with the heat-affected zones of adjacent welds. If it cannot be avoided, holes can be made in the weld or its heat-affected zone, but the following requirements must be met: the weld within 100 mm around the hole (or the diameter of the hole, if the equivalent aperture is greater than 100 mm) must pass flaw detection, and there must be no defects in the weld at the edges of the hole ； The welds at the pipe joint connections are stress-relieved through post-weld heat treatment. http://www.safe001.com/2003wen/guobiao3/086.htm These are the regulations regarding boilers: stress-relief annealing is required after welding, which involves heating the workpiece to around 650 degrees, holding it at that temperature for one hour, and then cooling it slowly inside the furnace