1. Dušan Ješić, International technology Management Academy, Trg D.Obradovića 7, 21000 Novi Sad, 2. Pavel Kovač, University of Novi Sad, Faculty of tehnical science, Serbia
3. Borislav Savković, Faculty of Technical Sciences, University of Novi Sad, Serbia
4. Dražen Sarjanović, Sara-Mont. Doo, Milića Rakić 7, Beograd, Serbia
5. D Golubović, University of Banja Luka, Faculty of Engineering, 7800 Banja Luka, V. Stepe Stepanovica 75, Republic of Srpska, Bosnia and Herzegovina
In this paper the heat treatment of ductile iron in tribological properties of contact pairs (pin and disk) was tested. Two types of nodular cast iron EN-GJS-500-7 and EN-GJS-700-2, austempered by isothermal and conventional procedure were tested. Friction and wear test was carried using the PIN and DISC Tribometer and PQ test. The methodology of classical and nodular cast iron isothermal austempering and a methodology in the examination are shown as well. By analyzing the results, it was concluded that the tribological characteristics depend on the structural characteristic of nodular cast iron which are determined by heat treatment. The tested sample, austempered by classic approach, gives the best indication in terms of friction, but it also showed the worst in terms of wear. In the same heat treatment regime EN-GJS-500-7 it is characterized by better tribological characteristics compared to EN-GJS-700-2. The obtained results can be used for proper selecting of type and regime of nodular cast iron heat treatment, with the aim for improving exploitation characteristics of contact pairs. By converting the laminar form of graphite into the nodular form, the modifier is added, prior to the spillage of smaller amounts of magnesium or Cerium as well as other materials if the specific properties of the nodular livers are required.
In this way, the concentration of the voltage due to the inclusion of graphite in the ductile iron is considerably lower than the gray cast.