Siberian Federal University (Krasnoyarsk, Russia):

T. R. Gilmanshina, Cand. Eng., Associate Prof., E-mail: gtr1977@mail.ru
S. A. Khudonogov, Senior Lecturer
S. I. Lytkina, Cand. Eng., Associate Prof.
N. S. Perfilyeva, Cand. Eng., Associate Prof.

Dr. Eng., Prof. I. E. Illarionov participated in this work.

Development of the technique for choice of the optimal composition of non-stick coatings based on the filling mass quality evaluation (taking into account the results of differential scanning calorimetry) is the aim of this research. Non-stick coating for iron casting based on filling mass and polyvinyl butyral lacquer was taken for investigations with the following relation – filling mass : polymer composition (2% polyvinyl butyral lacquer) = 1:1. The mixture of natural and mechanically activated graphite with their different correlation was used as a filling mass. Calculation of the conditional activation criterion displayed that the most optimal relation between selfdrying coatings of natural and mechanically activated graphite in a filling mass is 50:50. It was established in this case that increase of activated graphite in a filling mass of non-stick coatings leads to increase of density, toughness and reduced strength. The most essential improvement of the properties is observed if the content of activated graphite in a filling mass increased up to 50%. Additional increase of GLS-2A graphite content does not lead to substantial improvement of the properties. The developed non-stick coatings were tested during fabrication of the casting “Centrifugal soil pump. Internal pump shell” with mass 70 kg and size 510×615×128 mm, made of 320Kh20N (320Х20Н) iron. Use of non-stick coating on the base of the mixture of natural and mechanically activated graphite (with their relation 50:50) is characterized by decrease of burning-on thickness by 1.8 times (on the bottom surface of a casting) and by 1.9 times (on the side surface of a casting) in comparison with thickness values for non-painted castings. The obtained results can be explained in the following way: if we apply the coating containing 50% GLS-2 (ГЛС-2) and 50% GLS-2A (ГЛС-2А), large particles of natural graphite don’t penetrate in mould pores and remain on the surface, what leads to decrease of burning-on on the casting surface.

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