THE STUDY OF FRICTION COEFFICIENT OF SAMPLES WITH THE SPARK-INDUCED COATING

The author analyzed the cutting tool wear behaviour. The method of coatings spark-deposition was chosen as the method of durability extension. Friction criteria were chosen to be the criteria for cutting tool durability evaluation. The author defined the characteristics of influence of friction on cutting tool wear. The article gives the description of the design of experimental assembly for evaluation of test samples tribological characteristics and determines the laboratory testing modes. The author gives the list of materials used in testing both for coating formation and as the friction subjects. The procedure of estimation of friction coefficients in pairs “cutting tool – process material” is determined and explained. The author obtained the results of comparison friction tests of the samples hardened with STIM hard alloy using the spark-deposition of coating, and the rapid steel samples without coating when interacting with AK5M2 aluminum alloy, 40HGNM alloy structure steel and VCh 40-10 cast iron with or without cooling. On the basis of these results the diagrams of dependency of each experimental pair friction coefficient on cutting velocity were constructed. The author defines the minimal friction coefficients for various process materials from the tested list.   These data were processed in logarithmic system of coordinates. The dependencies on cutting velocity were obtained for determination of friction coefficient for various process materials. The author draws the conclusions and gives practical recommendations on selection of cutting tool optimal material when processing various structural materials under the existing machinery production conditions. It will allow to reduce metal-cutting tool flow and to improve economic effectiveness of edge cutting machining of machine elements.