How many longitudinal seams can there be in a tube section? ~

Do you intend to assemble a cylinder by using small sections of arc-shaped plates? The standards do specify only the minimum spacing, but personally I think the fewer longitudinal seams there are, the better, as they represent the weak points of the container

There is no standard that prohibits multiple longitudinal seams, but this is a sensitive issue; after all, since these areas are under the greatest stress, it’s better to have as few as possible

To ensure a uniform distribution of welds on boilers and pressure vessels and to prevent the accumulation of welding residual stresses, relevant regulations for boilers and pressure vessels specify the number and arrangement of welds. (1) When joining the cylinder sections, the length of the shortest section should be no less than 300 mm for medium and low pressure boilers, and no less than 600 mm for high pressure boilers ； For each cylinder section, the number of longitudinal welds: when the inner diameter Di of the cylinder is ≤ 1800 mm, there shall be no more than 2 joint welds; when Di > 1800 mm, there shall be no more than 3 joint welds ； The length of the outer arc between the centerlines of the two longitudinal welds in each cylinder section shall be not less than 300 mm for medium and low pressure boilers, and not less than 600 mm for high pressure boilers ； The longitudinal welds of adjacent tube sections should be offset from each other; the length of the outer arc between the centers of the two welds must be at least 3 times the thickness of the steel plate, and must also be at least 100 mm. (2) The head and tube sheet should be made from a single piece of steel plate as much as possible. If welding is necessary, when the inner diameter Di of the end caps and tube sheets is ≤ 2200 mm, there shall be no more than 1 weld seam; when Di > 2200 mm, there shall be no more than 2 weld seams ； The distance from the head splicing weld to the center line of the head shall not exceed 0.3Di; it must not pass through the flanging manhole, nor shall it be located on the flanging arc of the manhole ； The entire weld seam on the tube sheet must not be located on the bend radius, nor must it pass through the bend hole ； For a convex head composed of a central disc and sector plates, the weld directions are limited to radial and circumferential. The minimum distance between radial welds shall be not less than 3 times the wall thickness, and not less than 100 mm. (3) The requirements for the welds joining the furnace shell are the same as those for the cylinder. The lap welds of the U-shaped foot ring must be arranged radially, and the shortest arc length between the centerlines of the two welds should not be less than 300 mm. (4) The butt weld of the pipe shall not be located at the bent part of the pipe. For medium and low-pressure boilers, it is the distance from the center line of the butt weld on the straight section of the heating surface tube to the starting point of the tube’s curvature (or the outer wall of the boiler drum or header, or the edge of the tube support). At least 50 mm; for high-pressure boilers, the above distance must be at least 70 mm ； The distance from the center line of the pipe weld within the boiler area to the starting point of the pipe bend shall not be less than the outer diameter of the pipe, nor less than 100 mm ； On the straight sections of the heat-exposed tubes, the distance between butt welds must not be less than 150 mm. (5) Welded parts should be avoided in the main welds of the stressed components and their adjacent areas. If unavoidable, the weld of the welded part may pass through the main weld, rather than stopping at the weld or in its adjacent areas. (6) Holes, welds, and corners should be staggered. The distance between the edge of the opening and the weld shall be not less than 3 times the actual wall thickness at the opening, and not less than 100 mm. When making a hole in a convex head, the projected distance between the edge of the hole and the perimeter of the head should be no less than 10% of the outer diameter of the head. Holes and welds must not be located at the corners of components or on the bend radii, and should be kept at a certain distance away.

This requirement comes from the pot regulations; there is no specification regarding the number of longitudinal seams in the pressure vessel standards~

I can only tell you that if it has three longitudinal seams at this diameter. I won’t accept the delivery, hehe

The original poster is actually asking about on-site layout creation, right? Haha. . . Those upstairs have already answered that \"in order to ensure a uniform distribution of welds on boilers and pressure vessels and to avoid the accumulation of welding residual stresses, relevant regulations for boilers and pressure vessels specify the number and arrangement of welds.\" (1) When joining the cylinder sections, the length of the shortest section should be no less than 300 mm for medium and low pressure boilers, and no less than 600 mm for high pressure boilers ； For each cylinder section, the number of longitudinal welds: when the inner diameter Di of the cylinder is ≤ 1800 mm, there shall be no more than 2 joint welds; when Di > 1800 mm, there shall be no more than 3 joint welds ； The length of the outer arc between the centerlines of the two longitudinal welds in each cylinder section shall be not less than 300 mm for medium and low pressure boilers, and not less than 600 mm for high pressure boilers ； The longitudinal welds of adjacent tube sections should be offset from each other; the length of the outer arc between the centers of the two welds must be at least 3 times the thickness of the steel plate, and must also be at least 100 mm. ” The steel storage tank specifications state that \"the distance between two longitudinal welds should not be less than 300 mm\"”

In accordance with the applicable standard requirements for each； But the fewer welds, the better. With so many welds and them meeting the standards, there should be no problems ； But it is not aesthetically pleasing, which raises suspicions among users that scraps or leftover material have been used; it causes difficulties when delivering the product, and even gives some people… an excuse.

The fewer, the better; it also reduces the workload for colleagues

If it’s possible to use one vertical seam, avoid using two; this is the best option from both a labor and quality control perspective

If the plate length permits, it is best to have 1 weld; too many welds result in wasted labor and welding material, as well as increased risks.