What is the corrosion mechanism of NBR O-ring seals?
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This post was last edited by GUANGWEI8.26 on 2009-5-11 at 15:47. What is the principle behind the corrosion of Dingqing rubber O-rings? Thank you. The medium used is an ester (vinyl acetate); after use, it was observed that the O-rings expanded and became brittle. I wonder if anyone has used KTM’s high-pressure valves – they claim that their O-rings are made of fluororubber, but ours also expanded and became brittle, failing to provide a proper seal. We thought that fluororubber should be suitable for our applications.
What medium is used in the O-ring that everyone uses?
Fluororubber should work; are the O-rings counterfeit?
Ordinary fluororubber is sufficient; why isn’t a metal gasket used at high pressures?
Rubber O-rings definitely cannot come into contact with solvents; they will swell and deteriorate； We all use soft PTFE, and the results are good
Triply/biologically based EPDM O-rings – I wonder who has used them and what the results were like?
Triply/bielylene propylene rubber O-rings, which we use in mechanical seals for media such as amine solutions or alkaline solutions
Fluororubber is generally used in equipment operating with oils as the medium, while NBR is typically used in environments with water or liquefied gas. For corrosive media at slightly higher temperatures, PTFE is usually the preferred choice
Fluororubber should be quite stable; yours might not be genuine. It is possible to look up the solubility of those O-ring materials in vinyl acetate, as well as the temperature and pressure ranges for their use. Problems generally arise in these areas.
Vinyl acetate is a highly soluble organic solvent to which many rubbers cannot resist, as they swell as a result. It is normal for the fluororubber rings you use not to provide a sealing effect, as ordinary fluororubber cannot resist vinyl acetate either; it will swell and harden as well. Special grades need to be used. Please send me information about your situation; based on that, I will consider which type of rubber to choose.