What are the materials used for the valve core of high-pressure stop valves, and what is their valve structure?
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What are the materials used for the valve core of high-pressure stop valves, and what is their valve structure? Are the valve spools generally made of Hastelloy?
It is usually hardfaced with cemented carbide
It depends on what operating conditions you use it in Oxygen? High temperature? Is it still corrosive?
I’m a new student; I’m here to learn something new!
This is highly dependent on the temperature, corrosivity, and particle size of the medium; there is no universal rule.
The medium is in a rich state of decarburization solvent (NCMA), and the pressure is 100 bar; it is used to remove acids from natural gas. There is a control valve below, which serves as a bypass for that control valve. Currently, there is severe internal leakage, with the leakage increasing over time. This valve has not been operated before, and I think it’s unlikely that impurities are the cause – could corrosion be the reason?
I’m also very troubled by this issue; the internal leakage is getting worse and worse. I wonder whether cemented carbide could be corroded – what substances can it resist? I’m not sure if the decarburization solvent (NCMA) can cause corrosion to this material
The decarburization solvents commonly used are not highly corrosive; they generally do not cause corrosion to the cemented carbide Stellite used in surfacing. It’s also possible that impurities present at the time of installation, such as welding slag, caused scratches on the sealing surface; this can only be determined by examining the sealing surface itself after removing the valve. If the sealing is not proper, trying to open and close the valve several times might help. As for the corrosive effect of the decarburization solvent, it’s advisable to consult the supplier of that solvent.
I’ve tried turning it on and off several times, but this valve hasn’t moved at all. It wasn’t leaking before, then it started to leak slightly, and now the leakage is quite severe!