In one of the application, I need to use rotary valve, which contains stator made up of stainless steel and rotor with teflon material. When the rotary valve is connected with electric motor, stator-rotor rubbing starts. I need to find the coefficient of friction between stator and rotor during rotational operation. Stator and rotor are tightly pressed against each other by spring. The rotor is subjected to maximum of 22 bar pressure from back side (opposite site of rubbing).
Paresh, the COF can not be a material constant since it depends on many factors such as load, speed, rougness, temperature, adhesion, transfer film and so on.
Also in spite of low COF there may be intense wear due to intensive transfer of PTFE onto metal surface. Therefore, I believe that only tests carried out at conditions close to the real one may be helpful.
You should definitely check the coefficient of thermal expansion (with teflon being high and SS being low). This will give you an interference fit most likely.
Paresh, the COF can not be a material constant since it depends on many factors such as load, speed, rougness, temperature, adhesion, transfer film and so on.
Also in spite of low COF there may be intense wear due to intensive transfer of PTFE onto metal surface. Therefore, I believe that only tests carried out at conditions close to the real one may be helpful.
Data given in: www.igus.com; www.pgtec.de; www.lubron.com; www.polyfluoroltd.com
might be helpful.
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