Regarding the issue of the coefficient for welded joints with openings in SW6
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The welding joint coefficient for the cylinder body has been set at 0.85. I would like to ask: is the welding joint coefficient for the shell at the opening site 1? This means that 100% inspection of the welds at that opening is carried out to ensure their safety. Is this welding joint coefficient always 1 at such openings, with no possibility of it being 0.85? The welding joint coefficient for the takeover joint is 1, as seamless steel pipes are used and there is no welding involved; hence it is 1. If steel plates are welded together, then the welding joint coefficient will be the same as 0.85, which was chosen for the welding joints of the cylinder sections.
This post was last edited by zhangjuhua on 2018-7-12 at 20:22. If the hole is located on the weld seam, then if the length of the longitudinal weld seam is 0.85, it can’t be 1, right?
You open a hole in the head, then you use the welding coefficient for the cylinder body; check the input values on the side of the head. The amount that is missing needs to be compensated for, and whatever can be used for compensation constitutes design margin. This design margin requires the use of the welding coefficient
If it is driven onto the weld, the coefficient for the cylinder welding joint must be set at 0.85; as a precaution, 0.85 should be used if certainty cannot be ensured.
As a design, it is not possible to guarantee that the openings at the manufacturing stage will be located on the welds, especially with circumferential welds; this is sometimes unavoidable unless the design drawings specify exact requirements for the openings. Under normal circumstances, the opening is considered based on the weld coefficient of the main weld.
The head welding joint coefficient is also 0.85; I want to figure out these three values – I just captured them randomly
We have also encountered this issue; usually, when 0.85 is entered during the calculation of the front cylinder, the weld coefficient for the shell welds at the openings on the first page is automatically set to 1. Can it be understood that welds are not allowed at those openings, which is why the value is 1.0? Hope for a better answer; let’s discuss together :)
If the opening is not located on a weld, or if the weld is not within the effective reinforcement range of the opening, the welding joint coefficient for the shell at that opening is taken as 1; otherwise, it is 0.85. In addition, 100% radiographic inspection must be carried out over the specified weld length, with the inspection level depending on the equipment. To increase the inspection level, the coefficient for welded joints can be set to 1.
Well, my master told me that for the welding joints of the housing at the openings in the equipment we manufacture, a coefficient of 1 is used only; there is no such thing as 0.85, in order to ensure the quality of welding at those openings. But I think there is a 0.85 factor in the calculations; with 0.85, the calculated thickness tends to be on the higher side, which results in less excess area of the shell and thus a greater requirement for reinforcement area. This makes it easier to determine whether the selected reinforcement ring meets the requirements.