Improving the wear resistance of the clutch by composite galvanic chrome platingClutch wear resistance enhancement by composite galvanic chrome plating

At a time of developing technologies and innovations aimed at restoring and strengthening the working surfaces of machine parts, especially considering special equipment of the agro-industrial complex, technologies for obtaining high-quality chrome wear-resistant composite coatings are of great interest. Their multicomponent structure underlies operability improvement of the restored parts of agricultural machinery. This work presents the study of the wear resistance of samples with electroplated chrome plating coatings. The experimental results provided the basis for clarifying the mechanism of wear resistance of chrome-coated steels obtained by the standard electroplating method, as well as by the method of applying composite coatings. The experimental studies were performed on samples made of steel 30KHGSA TU 14-1-950-74 in the form of a cylinder, which take into account the operational characteristics of special tractor equipment and its working conditions. The size of cylindrical samples made of 30HGSA steel were the following: diameter 25 mm, length 150 mm. The authors used the electrolyte 200—250 g/l CrO3 and 2.0—2.5 g/l H2SO4 for deposition of coatings. An experimental installation was developed by a team of authors, which met the requirements for functional coatings formation on the surfaces of agricultural machinery parts and special equipment. The chrome coating quality criteria were analyzed in detail because of the high probability of excessive residual stresses. The entire cycle of preliminary preparation for coating was performed on these samples. Tests results and summary results on relative wear resistance are presented. In addition, data were obtained on the wear intensity of the studied samples under various loads on the friction unit. The conducted studies have shown that the existing claims about the advantages of composite coatings are confirmed, since the quantitative characteristics of samples wear demonstrated wear resistance increase when using the composite coating method. The type of samples wear with standard galvanic and chrome composite coatings turned out to be similar to that of serial friction pairs.