Welding issues in high-temperature centrifugal pumps
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The company has a heat transfer oil pump operating at 300°C; under normal production conditions, it stops working only 2–3 times per year. There is a drain outlet below the pump chamber, which is sealed with a threaded plug; leakage has been occurring at this plug area ； I now want to weld a section of pipe at the plug area and then attach a valve to it. . . . Could the ladies please advise me whether it’s possible to weld it? After welding, could there be issues such as \"the weld cracking due to high temperatures resulting from residual stresses\"?
Choosing the welding material based on the pump casing material should be no problem! ! !
Soldering it in place isn’t a solution; it’s necessary to find the cause of the leak – is it because the plug is too small, or is there some other reason? Improper welding can easily cause other problems!
I added copper gaskets inside, and now it doesn’t leak anymore!
Welding is no problem. This type of oil leakage is sometimes innate. In other words, the processing quality is not good; more raw tape can be wrapped around the plug.
Theoretically, it is possible to weld it, but in practice it is very difficult to do so well. Replacing the plug with another one and adding a copper gasket is the best and simplest method.
Heat transfer oil pump, temperature 300°C. Tape cannot be used. Cause of the problem: 1. Issue with the gasket material. Annealed copper gaskets, aluminum washers. 2. Thread machining accuracy, fit accuracy. 3. At high temperatures, the thermal expansion rates of the plug material and the pump material differ, resulting in a large clearance between them and leakage. The plugs are manufactured from materials with a high coefficient of thermal expansion. The higher the temperature, the tighter the fit.
As long as the welding material is chosen correctly, there will be no problems with welding!
Well, I originally wanted to add a metal gasket too, but the area where the plug is located isn’t flat........
Well, I’m going to try using a plug with a higher coefficient of expansion. . . . . Due to production reasons, it has been installed, but there is still a slight leak; a tray has been placed underneath as a temporary solution