Obrabotka Metallov 2015 No. 4

ОБРАБОТКА МЕТАЛЛОВ № 4 (69) 2015 28 ОБОРУДОВАНИЕ. ИНСТРУМЕНТЫ OBRABOTKAMETALLOV (METAL WORKING AND MATERIAL SCIENCE) N 4(69), October – December 2015, Pages 18–30 Select of abrasive wheels while pendular grinding of parts from titanium alloy VT22 by high roughness parameters Soler Ya. I. , Ph.D. (Engineering), Associate Professor, e-mail: solera@istu.irk.ru Mai D. S. , Ph.D. student, e-mail: mdsmm07@gmail.com National Research Irkutsk State Technical University, 83, Lermontov st., Irkutsk, 664074, Russian Federation Abstract At the present time, grinding of the titanium alloys parts is performed much less than other constructional materials that don’t meet the demands of branches of engineering industries: aircraft, rocket, energy and others. This is due to the sticking of chips on the working surface of the abrasive tools from silicon carbide and electrocorundum because of the high adhesion activity between the titanium and the traditional abrasives at cutting working temperatures. To solve this problem, the high porous wheels (HPW) made of cubic boron nitride CBN30 with 100% concentration on a bond V (K27), a pore-forming KF40, varied grains: B76, B126, B151 (GOST R 53922 – 2010) – and hardness: M and O (GOST R 52587 – 2006) were used to grind titanium workpieces. Additionally the Norton wheels from green silicon carbide with a normal porosity 39C (46; 60) K8 VK and with different grain size were tested. With account for the instability of the grinding process and the random nature of roughness formation, the observation analysis was led using the statistical approaches. It allowed considering the random variables (RV), the characteristics of the one-dimensional frequency distribution which are measures of position (mean, median) and measures of scattering (standard deviation, range and quartile latitudes (QL)). In the technical applications parametric and nonparametric statistical methods were used. The first direction requires that the RV have homoscedasticity and normal distribution that is not fully secured in this study. For this reason, the nonparametric method was selected priority. Its characteristics are medians and QL. It is established that varying the process variables for each group of instruments is insignificant by measures of position. Norton wheels provide reduction of roughness height 1.6 – 1.7 times in comparison with boron nitride HPW. These are recommended for the finishing grinding stage and HPW CBN30 – the preliminary to reduce the thermal effects on workpieces. By processing stability, the Norton wheels with grain 46 rank the first, and among boron nitride HPW - CBN30 B76 100 OV K27–KF40. Keywords : grinding, titanium alloy, roughness, statistic, mean, median, measure of position. DOI: 10.17212/1994-6309-2015-4-18-30 References 1. Balla O.M., Zamashchikov Yu.I., Livshits O.P. et al. Frezy i frezerovanie [Mills and milling]. Irkutsk, IrGTU Publ., 2006. 172 p. ISBN 5803803774 2. Chechulin B.B., Ushkov S.S., Razuvaeva I.N., Gol’dfain V.N. Titanovye splavy v mashinostroenii [Titanium alloys in mechanical engineering]. Leningrad, Mashinostroenie Publ., 1977. 248 p. 3. Nosenko V.A., Nosenko S.V. Tekhnologiya shlifovaniya metallov [Metal grinding technology]. Stary Oskol, TNT Publ., 2013. 616 p. ISBN 978-5-94178-373-1 4. Leyens C., Peters M., eds. Titanium and titanium alloys: fundamentals and applications. Weinheim, Wiley- VCH Verlag, 2003. 532 p. ISBN 978-3-527-30534-6 5. Kremen’ Z.I., Yur’ev V.G. Shlifovanie superabrazivami vysokoplastichnykh splavov [Super abrasive grinding of superplastic alloys]. Saint Petersburg, St. Petersburg Polytechnic University Publ., 2013. 167 p. ISBN 978-5-7422- 1034-1 6. Nosenko S.V., Nosenko V.A., Krutinova A.A., Kremenetskii L.L. Issledovanie khimicheskogo sostava poverkhnostnogo sloya titanovogo splava pri shlifovanii ego krugom iz karbida kremniya bez ispol’zovaniya SOTS [The study of the chemical composition of the surface layer of the titanium alloy at grinding by silicon carbide wheel without lubricant-cooling agent]. STIN – Russian Engineering Research , 2015, no. 1, pp. 26–29. (In Russian)