Siberian Federal University (Krasnoyarsk, Germany):

T. R. Gilmanshina, Cand. Eng., Associate Prof., e-mail: gtr1977@mail.ru
A. A. Kovaleva, Cand. Eng., Associate Prof., e-mail: angeli-kovaleva@yandex.ru
S. I. Lytkina, Cand. Eng., Associate Prof., e-mail: tmilp@rambler.ru

I. N. Ulyanov Chuvash State University (Cheboksary, Russia):

I. E. Illarionov, Dr. Eng., Prof, Head of the Chair “Materials science and metallurgical processes”

The study of dependence of the cast iron castings surface quality in relation to the burning-in thickness, graphite inclusions parameters on the method of the natural graphite preparation has been presented. For research, an aqueous graphite coating based on natural, mechanically, chemically and chemically-mechanically activated graphite was chosen. The structure of cast iron was investigated according to GOST 3443–87. X-ray microanalysis of the burning-in layer was carried out using the EVO 50 XVP scanning microscope. The thickness of the castings burning-in layer was determined using the QNIX 7500 thickness gauge. Microstructure analysis was carried out using the Axio OberServert.A1m microscope. The research results showed that the replacement of natural graphite with mechanically, chemically and chemically-mechanically activated graphite brings about a decrease in the burning-in layer thickness from 3370–3500 to 900–1000, 600–700 and 20–25 μm, respectively. In this case, the surface area of the casting with burning-in is reduced from 85 (for natural graphite) to ≤40 (for mechanically and chemically activated graphite) and ≤5 (for chemically-mechanically activated graphite). Introduction of mechanical activation as a stage of graphite preparation enables to reduce the castings surface roughness from Rz40 to Rz20. In addition, the use of activated graphite in the composition of antiburning coatings decreases the burning-in thickness, the graphite inclusions size in the surface layer of castings. The sizes of graphite inclusions in the core of the castings are the same for all samples studied.

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