For the welding of the partition plate in a double-shell pass, is it done as continuous double-sided welding or can it be done in intermittent welds?
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Question: In a heat exchanger with a DN800 shell, should the partition plate between the two flow paths be welded continuously on both sides, or should welding be done in intervals to prevent deformation?
The partitions and tube boxes should be welded continuously on both sides; if they are made of carbon steel or low-alloy steel, post-weld heat treatment is also required. Welding can affect the sealing surfaces of the tube box flanges, and post-weld heat treatment is necessary for those made of carbon steel or low-alloy steel. The sealing surfaces of the tube box flanges should be processed after welding (after heat treatment).
This partition should be fully welded to prevent cross-contamination
The casing of DN800 is too small; can a welder get inside to carry out welding? If only preventing short circuits in the shell side is considered, you can refer to clause 6.8.4.4 of GB/T151, which discusses the use of elastic sealing gaskets to prevent such short circuits.
The partition in the shell side is connected to the tube bundle, and the sealing between it and the shell side of the shell is achieved through sealing strips.
I want to ask whether continuous angular seam welding can cause deformation of the housing. If the component only needs to have a sealing function and strength is not required, it is possible to carry out intermittent welding on both sides, as long as the welds on those two sides remain continuous so that the medium does not leak between chambers. I was wondering if this approach would work
Regarding the intermittent welding you mentioned, I’ve thought about your manufacturing plan and there are a few issues; please consider how to address them: 1. Weld intermittently on both sides, but ensure that the welds on each side remain continuous. I’ve thought about your idea – a bevel must be created on the side of the partition in order to prevent the medium from flowing across it. What is the bevel angle? Leave roots or not? Can full penetration be guaranteed after leaving the root? Liquid will accumulate in the area between the two intermittent welds; could corrosion occur if the concentration of this liquid is too high? 2. With intermittent welding, it is not possible to avoid welding around the shell’s circumferential seams; moreover, the welds on the partitions cannot overlap those circumferential seams. How can you ensure no cross-flow occurs in such areas? If you insist on pressing the ring seam, can your RT inspection of that ring seam pass? These are my views; if we have different opinions, we can continue to discuss them.
The partition plates do not require grooves; intermittent welding is performed on both sides, but the welding must ensure sealing. The ring seam was also welded; no RT fabric was used in this area.