Student M. M., Hvozdets'kyi V. M., Holovchuk M. Y. Influence of chemical composition of powder wire on structure and determinants of coatings of different chemical composition.

Abstract

The properties of electric arc coatings from powdered wires are investigated. Determine the content of doping elements in powder wire, which increase resistance to wear of the coating. The composition of the powder wire under the spraying of which in the microcrystal coating is not formed is established. The quantitative content of doping elements that reduce the porosity and content of oxides in coatings is determined. Coatings determine the carbon content and boron, which provides a minimum level of stress. Molybdenum oxide forms fusible oxides in the process of spraying and protects the melt from oxidation. When spraying the coating a large part of carbon burns out and in the coating remains no more than 0,6 - 0,7 % by weight. This amount of carbon in the coating provides a low level of residual tensile stress due to the formation of a martensitic matrix and, as a consequence, a high wear resistance of the coatings. In the presence of boron in the coating, fine-dispersed borides are formed in its structure, which determine the high wear resistance of the coating. At high content of boron, 5 % by weight. in PD 50ХН2ГР5 the hardness of the coating is significantly increased, however, the coating creates a grid of microcracks, which significantly reduces the wear resistance of the coatings. Key words: electric arc metalization, powder wires, coating, wear resistance.