Can a necked flat welding flange be welded directly to elbows?
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Can a necked flat welding flange be welded directly to a reducer? I think direct welding is not possible, because when the tees are inserted into the flange, a cavity is formed between the tees and the inner wall of the flange, making it difficult to ensure proper welding. But after asking several construction companies, they all said there was no problem and that welding could be carried out directly. I checked some standards but couldn’t find any relevant regulations. I would appreciate it if the experts could advise on whether welding can be done directly.
It can be connected as long as it does not affect the installation of the flange bolts. If it is necessary to insert something because the pipe diameter is too small, a section can be cut off to adjust the diameter to fit the flange connection size. The selection of pipe fittings should be done in a standardized manner, with re-matching required, especially for pipes under high pressure; it cannot be taken lightly.
Theoretically, it’s not possible; a short section of straight pipe is required. I can’t remember exactly which standard states this! During on-site construction, this is the method used for the inlets and outlets of many pumps (plate butt welding), and no problems have arisen during operation. Personally, I think the construction party does this just to avoid having to weld one more seam
This is not allowed; it represents a clever trick by some construction companies as well as a one-sided understanding
In fact, it’s even less allowed; you can ask them to redo it right there if you see it
And it’s impossible to insert it into the flange during welding
This design is not standard; as a result, the installation of the bolts may be affected