Detailed knowledge of the mechanical seal Corrosion Protection |
Because mechanical seals particular layout and working environment and conditions are not the same, the shape of corrosion damage are also diverse. Tetrafluoroethylene seals, PTFE gasket seals and other mechanical damage to the common main methods of corrosion damage, thermal damage and mechanical damage. During corrosion damage greater harm.
A metal ring corrosion
1, the appearance of uniform corrosion. If the metal ring appearance touch corrosive media, while the metal itself and impatience corrosion, it will attack the appearance of corrosion, the phenomenon is leaked, pre-worn, damaged, sound and so on. Appearance of uniform corrosion of metal film and no film has two shapes, no film is the risk of metal corrosion, stress corrosion called break, use surfacing alloy and cast iron, tungsten carbide, titanium and other sealing ring, simply showing stress corrosion break. Corrosion processes to speed definitely make galvanic corrosion worse.
2, stress corrosion break. Metal cartridge mechanical seals, wear and corrosion effects in conjunction tensile stress. F4 ring filled corrosion populated mainly refers to the selection of corrosion, dissolution or transformation damage. Such as hydrofluoric acid, the glass fiber molecules hot corrosion, these cracks to communicate the entire seal face, the end face of accelerated wear and tear, so that leaked amount added.
Two non-metallic ring corrosion
A graphite ring corrosion. Company Information Network comes with a resin-impregnated graphite impermeable ring, its corrosion has three reasons: First, when the end face of overheating when the temperature is higher than 180oC, resin impregnated graphite rings to fold away, so ring wear lower; Second, if the selection of resin impregnated wrong, so sealing the cooling system and establish factory sealed, it is mainly the fault of the formation of the selection. Film of corrosion, passivation film usually has the effect of maintaining properties, but the metal seal ring used materials such as stainless steel, cobalt, chromium alloy, its appearance in the end face of the friction in the passive film is damaged, the new under hypoxic conditions the film is difficult to generate, the selection of corrosion resistant resin-impregnated, the choice of a high pressure impregnation, it is necessary to add the immersion depth.
2, the oxidation of the graphite ring. In an oxidizing medium, or the end face of a conflict in a poor dry-cooling, the onset temperature of 350 ~ 40o ℃ graphite ring enables reaction with oxygen attack, seizure CO, gas can end surface roughening, or even break. Non-metallic ring in the chemical medium and stress effects together will break.
3, polytetrafluoroethylene (PTFE gasket) corrosion of the sealing ring. Will attack the chemical changes in the medium, but also to reduce the wear resistance; third resin impregnation depth is not, when rubbed impregnated layer, wear is reduced. F4 filling such as glass fiber, the first attack in the thin zone cracks, and then to develop in depth, attack break, crack sealing ring is usually radial divergence can be one or more so. Graphite, metal powder in order to progress their temperature resistance, abrasion resistance. F4 ring filled corrosion populated mainly refers to the selection of corrosion, dissolution or transformation damage. Such as hydrofluoric acid, the glass fiber molecules hot corrosion, so what things should be filled, as the case may be.
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