2019-2-23 8:27:29 点击率：
good mechanical technological parameters,e.g. high abrasion resistance, low gas permeability and good resistance to mineral oil based lubricating oils and greases, hydraulic oils,highlynon-flammable hydraulic fluids hfa, hfb, hfc, silicone oils and greases, water up to approx. 80°c.nbr is generally not resistant to polar solvents, glycol-based brake fluids and highly non-flammable hydraulic fluids hfd. it has a low resistance to ozone, weathering and ageing. in most hydraulic applications this has no effect because the hydraulicseals are installed internally in the hydraulic components.
nbr is frequently used in the hydraulic field due to its good mechanical characteristics and resistance to mineral oil based lubricating oils and greases.
fkm is a fluorocarbon elastomer with high thermal and chemical
resistance.its broad spectrum of resistance and relatively good
compression set, even at high temperatures.
fkm is known especially for its non-
flammability, low gas permeability and excellent
resistance to ozone, weathering and aging.
pu materials display higher mechanical strength,high abrasion, wear and extrusion resistance, high pressure load capacity,as well as a high tear and elongation at break resistance. also have good flexibility and very good ageing and ozone resistance.
pu materials are suitable for application in
mineral oils and greases,hydraulic oils, silicone
oils and greases, highly non-flammable hydraulic fluids hfa and hfb and water up
have high wear resistance, good low temperature resistance and high pressure load and extrusion resistance. in addition rubber fabric hydraulic seals are inherently very dimensionally stable and have a low moisture expansion tendency in hydraulic media.
particularly well suited for rough application
conditions, such as in mobile hydraulics or other
heavy duty applications.
vmqshows excellent heat resistance, cold flexibility,dielectric properties and especially good resistance to weather, ozone and uv rays.not suitable for oil based fluid.
foodstuff and cryogenic engineering.
acm shows excellent resistance to ozone, weathering and hot air, although it shows only a medium physical strength,low elasticity and a relatively limited low temperature capability.
acm materials are mainly used in automotive applications which
require special resistance to lubricants containing many additives
(incl. sulfur) at high temperatures.
epdm shows good heat, ozone and aging resistance. in addition they also exhibit high levels of elasticity, good low temperature behavior as well as good insulating properties
epdm can often be found in applications with
brake fluids (based on glycol) and hot water.
hnbr shows good mechanical properties.the operating temperature of hnbr ranges between -30°c and 140°c(for a short period of time up to 160°c) in contact with mineral oils.special types can be used down to -40°c.
mainly use in mineral oil at high temperature.
in general the cr materials show relatively good resistances to ozone, weathering, chemicals and aging.also they show good nonflammability, good mechanical properties and cold flexibility.
cr materials are found in sealing applications such as refrigerants, for outdoor applications.
ptfe display almost universal chemical resistance,an extremely low friction value which results in very good sliding characteristics, no stick-slip effect,particular rigidity and almost unlimited ozone, weathering and ageing resistance. ptfe is impervious to almost all known hydraulic media, lubricants,chemicals and solvents.ptfe is non-flammable and so does not constitute an additional hazard in case of fire.pure ptfe is not totally without disadvantages as it has a tendency to cold flow or crawl under pressure load.these weaknesses are counteracted by the use of seal compounds mixed with fillers.
pure ptfe is particularly suitable for food and
beverage applications, pharmaceuticals and
medical application areas. ptfe is not or only
slightly elastic. for this reason, ptfe seal
elements are activated by elastic energising
elements in the form of o-rings or stainless steel springs. compounds filled with bronze for example, give ptfe the ability to adapt to most application conditions.
pa has a good wear resistance.water absorption and resulting change
in volume can be catered for by increasing housing tolerances.
pa is a high-molecular polyamide from which
even large elements can be produced
economically,is used for large bearings and
excellent sliding characteristics, particularly in the dry-running range
of the bearing element.the material is tough and maintains good
stability of shape at different temperatures. its chemical structure also
gives it high resistance to various fluids with low water absorbtion.
particularly suitable for the functions which
guide rings and back-up rings are required to
utra high molecular
excellent wear and abrasion resistance.
best in aqueous solutions and cryogenic
|酚醛夹布phenolic resin with
with the selection of the optimal material combinations (fabric/resin), a
long product life, high restoring force, low friction and very high
contact pressure (load capacity) can be achieved. no moisture
expansion in water; or measurable absorption of water.
selected for application areas in hydraulics with
high loads and shear forces,heavry duty wear
ring for example.