Is the thickness of the pressure vessel shell compliant?

During welding, the outer wall must also have shifted outward, right?

Design and manufacturing have been mixed up, haven’t they?

During the manufacturing process, the misalignment of welds must meet the requirements specified in GB150.4; this is separate from the design thickness of the container

However, although such a large amount of misalignment in stainless steel containers meets the standard requirements, it looks very unsightly and affects the manufacturer’s reputation

Design is design, and manufacturing is manufacturing; they cannot be confused

If we have to argue, then take the welds into consideration

It fails; firstly, there is confusion in the design and manufacturing process, and secondly, the negative deviation in the thickness of the sheets needs to be taken into account – it is generally 0.3 mm, which indicates that the design regarding thickness is unreasonable.

First, assume the hypothetical scenario proposed by the original poster is valid; therefore, the issue of insufficient strength resulting from 11mm being less than the calculated thickness arises from treating the misalignment at the weld seam as one that is subjected only to overall membrane stress. In actual containers under pressure, at the weld misalignment areas, the stress is not merely a uniform film stress similar to that in the base material; there are also local film stresses, local bending stresses, and so on. The stress conditions are very complex. Similar situations occur at the joints where pipes are connected to the cylinder, at areas with large angles, and at areas with large burrs. There are many finite element analysis resources available online; if the poster is interested, they can take a look. So how to deal with so many complex stress areas? We can’t conduct a stress analysis on every single part, right? Therefore, GB150 specifies allowable ranges for the misalignment amount to ensure that the stress levels at the misaligned areas remain below the allowable values. It also provides recommended methods for connecting the nozzles to the shell, so as to ensure that the welds connecting them have equal strength to that of the shell itself. Additionally, it specifies allowable ranges for the weld height, in order to prevent the peak stress from exceeding permissible limits. In summary, as long as the misalignment is within the standard allowable range, the alignment between the container components is considered to be satisfactory.

A standard is a set of guidelines that include safety factors; when determining calculation formulas and allowable stresses, the errors that occur during the manufacturing process are taken into account. As long as these errors remain within acceptable limits, the results obtained using those formulas and allowable stresses are sufficiently safe. Edge misalignment is also a type of error that occurs during construction; the standards specify that the allowable value for such misalignment is one that meets the required safety factor, so it can be considered safe. When the pressure is low and the wall thickness is small, manufacturing errors appear to be relatively large. However, the difficulty of rolling such thin sheets is also low, and the stiffness of the sheets is low as well; therefore, the actual deviation may not be that large. Furthermore, welds have their own structure, and standards specify requirements for the types of welded joints; the issue of misalignment should be taken into account here. That’s how I understand it

The misaligned edges should be repaired to create a smooth transition; after repair, check the minimum thickness.