Can a single cylinder section of a pressure vessel be tailor welded?

I think there can be more than two A-seams, as long as the weld spacing can meet the requirements of 150.4 and 6.5.5.

Let me tell you my opinion first. If there are any mistakes, please feel free to correct me. A single barrel section can be tailor welded (in other words, it can have 2 longitudinal welds). Cause analysis 1: As the equipment becomes larger and larger, the diameter of the equipment becomes larger and larger. Currently, there are more and more tower equipment with a diameter of 6 meters and 8 meters in petrochemical equipment. However, transportation restrictions ultimately lead to the length of the plate. If two longitudinal welds are not allowed, it may not be possible to implement large-diameter equipment. Cause analysis 2: GB/T 150.4-2011 6.5.5 c) stipulates the minimum length requirements of a single barrel section. The starting point is to avoid the use of leftover materials and scraps by manufacturing units and to avoid excessive welding joints that affect the quality of the equipment. If understood from this extension, a single barrel section should also be splicable (diameter limit). How to control the minimum spacing between adjacent longitudinal welds of a single longitudinal weld? Personally, I think that a single barrel section is only allowed to have a maximum of 2 longitudinal welds (the more welds, the harder it is to ensure quality). The layout of the welds should consider not only the influence of the heat affected zone of the welded joint, but also the distance requirements for non-destructive testing. The distance between adjacent A seams should be as large as possible, at least greater than 300mm, and should be controlled to 0.5D (symmetrical arrangement).

There is no relevant provision or description for the distance of "single barrel section" type A joints in Article 6.5.5.

In addition, I personally feel that if a single cylinder section has more than one weld, it will be more difficult to control the rolling difficulty and the roundness of the cylinder.

So I think this issue can be solved by thinking about it. There is no need to stipulate how many A-seams a single barrel section can have. There can be 2 or even more than 2, because when the A-seams can be minimized (welding quality and non-destructive inspection), as long as you can buy such a long plate, you will definitely try to consider only one A-seam. Why do you need to patch the seams?

A friend from a manufacturing unit asked me a question today and asked me where the standards were stipulated. I was stunned by the question. So I still want to find out.

You can tell him that as long as you want, it doesn't matter how many welds are, as long as they can meet the spacing requirements of adjacent barrel section welds, but the quality of the welds must be guaranteed:lol:lol:lol

Discussions are discussions, but bad ideas cannot be made randomly. There has to be a basic judgment and basis, right? What do you think? Although you can do whatever you say without any prohibition, you can't walk on the edge of the law, right?

The lengths of our tube section boards are all purchased according to the calculated circumference, and each section has one A seam. Who would eat too much and make so many seams? Right, sir? * * !

The common practice is definitely to use one weld, but there are indeed bosses who want to use two welds to save costs for various reasons. In the Chinese market, there are only things you can't think of. All kinds of weird events are commonplace. Let's just discuss the technical issues. If you want to think about it, just think about it. If you think it's meaningless and unnecessary, don't take it to heart. It's just a discussion anyway.