Estimation of triboelectric properties of high-speed steels

Introduction. The paper is devoted to forecasting the operational properties of the existing and newly developed high speed steels depending on their chemical composition by the investigation of thermodynamic processes in the friction zone under cutting, and by receiving analytical dependences for evaluating friction and wear characteristics. The work objective is the prediction of wear resistance of high speed steels on the base of the structural sensitive parameters of the absolute or relative thermo-EMF and entropy of the material which can be calculated by the additivity rule at the known chemical composition. Materials and Methods . The theoretical relationship between the change in entropy of steels and their thermo-EMF is obtained. According to it, a smaller value of the absolute thermo-EMF corresponds to a larger value of the material entropy. This theoretical relationship is experimentally tested on various compositions of high speed steels. Research Results. To determine the relationship between entropy as a thermoelectric characteristic of high speed steels and their wear resistance, experimental tests on friction for the cylindrical samples of high speed steels of different types, and study on the wear properties of drills under steels machining are carried out. Measurements of relative thermo-EMF of these samples are performed; and their absolute values are calculated. The results of these tests show maximum wear resistance of high-speed steels having high values of entropy and low values of the absolute (relative) thermo-EMF. Discussion and Conclusions . The relationship between the wear resistance parameters of high speed steels and their structurally-sensitive characteristics at the micro-level - entropy and absolute thermo-EMF, is established. To reduce wear during friction and cutting, it is necessary to apply the types of high speed steels with maximal entropy and minimal thermo-EMF. Entropy, which with ease can be calculated on the known chemical composition of the material, can be used to assess the operating properties and to predict the wear resistance of both existing and newly developed compositions of high speed steels.

инструментальные режущие материалы, быстрорежущие стали, термо-ЭДС, энтропия, износостойкость, высокоэнтропийные быстрорежущие стали, tool cutting materials, high speed steels, thermo-EMF, entropy, wear resistance, high entropy quick-speed steels

1. Ryzhkin, A.A. Obrabotka materialov rezaniem: fizicheskie osnovy. [Processing of materials by cutting: physical basics.] Rostov-on-Don: DSTU Publ. Centre, 1996, 242 p. (in Russian).

2. Ryzhkin, A.A. Sinergetika iznashivaniya instrumental'nykh rezhushchikh materialov (triboelektricheskiy aspekt). [Synergetics of cutting-tool materials wear (triboelectric aspect)]. Rostov-on-Don: DSTU Publ. Centre, 2004, 322 p. (in Russian).

3. Ryzhkin, A.A., Ilyasov, V.V. O svyazi mezhdu iznosostoykost'yu i fizicheskimi svoystvami instrumental'nykh materialov. [On the relationship between wear resistance and physical properties of tool materials.]Vestnik Mashinostroeniya, 2000, no. 12, pp. 32–40 (in Russian).

4. Morgner, W., Becker, B., Spies, H.-J. Untersuchung mikroskopischer Inhomogenitaten in Stahlen durch Kontaktthermokraftmessung. WZ der TH Otto von Goricke, Magdeburg, 1970, Heft 1, №14, S. 3–11.

5. Ryzhkin, A.A., et al. Vybor optimal'nykh rezhimov iznashivaniya po triboelektricheskim kharakteristikam zony rezaniya. [Selection of optimal wear modes due to triboelectric characteristics of the cutting zone.] Problemy triboelektrokhimii: sb. trudov Mezhdunar. nauch.-tekhn. konf. [Problems of triboelectrochemistry: Proc. Int. Sci.-Tech. Conf.] Novocherkassk, 2006, pp. 207–210 (in Russian).

6. Ryshkin, A. Uber die elektrischen Erscheinungen beim Spanen von Metallen. WZ der Karl-Marx-Stadt, 1973, Heft 4, №1, S.711–725.

7. Karapetyants, M.K. Vvedenie v teoriyu khimicheskikh protsessov. [Introduction to the theory of chemical processes.] Moscow: Vysshaya shkola, 1975, 330 p. (in Russian).

8. Ryzhkin, A.A. et al. Otsenka rabotosposobnosti vysokoentropiynykh instrumental'nykh rezhushchikh materialov. [Determination of the efficiency of high- entropy cutting tool materials.] Journal of Friction and Wear, 2016, no. 1, pp. 60– 69 (in Russian).

9. Ryzhkin, A.A. et al. Iznosostoykost' novykh marok bystrorezhushchikh staley. [Wear resistance of new types of high-speed steels.] Metallorezhushchie stanki i progressivnye metody obrabotki metallov rezaniem: sbornik statey. [Metalcutting machines and advanced methods of metal cutting: coll. of sci. papers.] Rostov-on- Don: RISKhM Publ. Centre, 1972, pp. 82–87 (in Russian).

10. Montgomery, D.C. Design and analysis of experiments. Eighth edition, John Wiley & Sons, 2013, 757 p.