Detailed knowledge of the mechanical seal corrosion protection

    Due to the special structure of the different forms of mechanical seal and the working environment and conditions, corrosion damage morphology are also diverse . Common forms of mechanical damage to seals PTFE seals, PTFE gaskets and other major corrosion damage , heat damage and mechanical damage. Greater dangers which corrosion damage .

    One metal ring corrosion

    1 , uniform surface corrosion. If the metal ring surface contact with corrosive media , and the metal itself is prone to corrosion , it will produce a surface corrosion, the phenomenon is leaking , early wear , damage, sound and so on. Uniform corrosion of metal surfaces and non- film forming two forms of metal corrosion is no risk of the film , known as stress corrosion cracking , and the choice of welding iron carbide , tungsten carbide , and titanium carbide seal ring is prone to stress corrosion rupture. Etching process with a constant speed , so that galvanic corrosion intensified.

    2 , stress corrosion cracking . Metal corrosion and tensile stress at the same time the role of abrasion resistance. Fill F4 ring corrosion populated mainly refers to selective corrosion , dissolution or deterioration destruction. As hydrofluoric acid , the thermal etching of glass fiber molecule , these cracks communicate the seal faces , accelerated wear of the end face , an increase of leakage .

    Two non-metallic ring corrosion

    1 , graphite ring corrosion. Enterprise Information Network mentioned ring impregnated with a resin impermeable graphite, its corrosion for three reasons: First, when the end face of overheating when the temperature is higher than 180oC , to break away from the resin impregnated graphite ring, the ring wear fall ; Second, if the inappropriate choice of resin impregnated , so the establishment sealed cooling system , which is mainly caused by the wrong selection . Corrosion film , the passivation film generally has a protective effect characteristics , but the metal seal ring of material, such as a passivation film of stainless steel , cobalt, chromium alloy surface at the end surface of the friction damage , under hypoxic conditions New membranes difficult to generate , select corrosion resistant resin-impregnated , using high pressure impregnation , impregnation depth increase is necessary .

    2 , graphite ring oxidation. In an oxidizing medium, dry friction or poor end surface cooling , a temperature of 350 ~ 40o ℃ graphite ring can react with oxygen to produce CO, gas can end surface roughening , or even rupture . Non-metallic ring in the chemical and stress , while the role of the media , will be broken.

    3 , polytetrafluoroethylene ( PTFE gaskets ) of the sealing ring corrosion. Chemistry occurs in the medium changes, the wear resistance decreased ; Third resin impregnated deep enough, when the impregnated layer is rubbed , the wear resistance . F4 filler such as glass fiber , a weak area in the fracture is first generated , and then the further development , to rupture , crack sealing ring generally radially divergent , and may be one or more . Graphite, metal powder to improve its heat resistance , wear resistance. Fill F4 ring corrosion populated mainly refers to selective corrosion , dissolution or deterioration destruction. As in hydrofluoric acid , the glass fiber molecules hot corrosion , so what things should be filled , as the case may be.