INVESTIGATION OF TRIBOLOGICAL PROPERTIES OF TOOTHED HARROW COATED WITH DIFFERENT SURFACE COATING METHODS
Project no. 20452 · Status: Kapanmış (Yayın bekleniyor) · 2019
Summary
Soil tillage in agricultural production has great importance for the continuing operations. Various machines such as mold board plows, cultivators and harrows are used in tillage. Wear occurs in the active components of tillage machines and causes the machines to lose the expected functionality of them by over the time. Although different methods and procedures are carried out to reduce the effects of wear as much as possible, problems still remain. In this study, new methods were tested on a toothed harrow active element in order to reduce the wear effects. For this purpose, different coating materials and methods were applied to the harrow teeth to increase wear resistance and consequently wear behavior was investigated. In this study, harrow teeth were coated with four different coating methods and special alloy powders. As coating materials, TiCN was used in PVD method and WC-Ni-Co-Cr-Si-Fe-B powder mixture was used in HVOF method. Uncoated (witness – control group) sample (S), PVD (2 µm thickness) coated sample (A), PVD (5 µm thickness) coated sample (B), HVOF (500 µm thickness) coated sample (C) and HVOF + PVD methods together (500 µm + 2 µm thickness) coated sample (D) was prepared and used in wear tests. The tests were carried out in the laboratory conditions for all harrow teeth at a 50 km wear distance with the aid of a system which has double speed gearbox and converts the rotational motion into a circular motion. As a result of the wear tests in the same conditions, the total material loss was determined 3.99 g in uncoated (witness) samples. Due to the increasing wear resistance, less loss was observed in the samples treated with coating. Sample A has the lowest value with a material loss of 0.14 g. The A coated samples, followed from low to high with D sample 0.18 g, B sample 0.19 g and C sample 0.28 g respectively. When the coating method and materials were compared, it was calculated that the applied coating processes reduced the wear loss by an average of 21.5 times. Keywords: Harrow Teeth, Wear, PVD, HVOF, Coating.