Proceedings of SerbiaTrib '13

ollers, that is, the normal contact loadtemperaturee are shown in Table 1:150dTF [N][mm][ ⁰ C]121086412108641210864121086412108641210864121086412108640.174101 0.120903 0.077378 0.043525 0.019345 0.174101 0.120903 0.077378 0.043525 0.019345 0.174101 0.120903 0.077378 0.043525 0.019345 0.174101 0.120903 0.077378 0.043525 0.019345 0.174101 0.120903 0.077378 0.043525 0.019345 0.174101 0.120903 0.077378 0.043525 0.019345 0.174101 0.120903 0.077378 0.043525 0.019345 0.174101 0.120903 0.077378 0.043525 0.019345 202020202050505050501001001001001001501501501501502002002002002002502502502502503003003003003003503503503503500.1965810.1852610.2956190.2438110.2296940.2102290.2124840.2181930.2855140.2273320.1908950.2045410.2056290.2436610.2400490.3104430.2844180.2890480.3309710.3515920.2400520.2286210.234370.3408610.4591680.2702270.2867180.3778370.3225730.5229930.2917250.3666280.5479850.5717560.3891940.2796390.3417810.3540480.3152330.462363andAccording to the data from Table 1 was formeddiagram of static friction coefficientwhichdepending on the normal load and temperatures towhich contact pairs are pre-treated.Figure 5. The static coefficient of friction whichdepending on o the normal l load and temperature4. DISCUSSIOONBased on theoreticalconsiderationsandexperimental investigationss it can be concluded thattthe physical principle p off measuringthe staticcoefficient of friction f overr the steep plane can beeffectively applied in testing conditions at highhvalues of temperature andd low valuess of contacttpressures.It requires a certainprecisionmeasurement instrumentation (precisionmeasuringequipment - Tribometer),Twhich is realized withequipment used for conducting this tests. Theaccuracy of the measurement was the angle of Δα =1'. A large number of measurements and a numberof repetitions of experiments under identicalconditions alloww statistical analysis of the t results ofmeasurements to t minimize random error.Experimental results of f investigation presentedin the form of 3D 3 diagram in Figure 5 indicates thattfor given conditions the temperature treatment t ofcontact pairs have substantial effect on the value ofstaticcoefficient of friction.Theessentialdependenceof frictioncoefficientfromtemperature, which can be seen from the t diagram,expressed that for temperature change from 50⁰ Cto 300⁰ C value of the static frictioncoefficientincreases nearlyy two times. Based on the foregoing,it is obvious that the changes of static frictioncoefficient arise from temperatureeffect onmaterial in contact. It is likely that preheating ofcontact pairs above the temperature values close to200⁰C leads too physical changes in the surfacelayers of contact pairs.With diagram shown inn Figure 5 iss possible toanalyze the effect of normal load on the staticcoefficient of friction. f Normal load in the range of0.019 to 0, 17 N is used during experiment. Fromthe diagram it can c be seen that the minimum valuesof the normal load l in the entire temperature range,13 th International Conference C onn Tribology – Serbiatrib’13