The peculiarities of coating formation by the gas-thermal method at application of powder wires are considered. This is due to the presence of pores and solid inclusions in the resulting layer. Therefore, it is important to investigate the influence of the mechanical processing parameters and the composition of the powder wire on the roughness of the polished surface of the electric arc coatings. Coatings in the thickness of 1.2 ... 1.5 mm were applied with a serial electro-arc metalizer EM-14 on a pre-treated surface of both flat and cylindrical specimens. The microstructure and chemical composition of the coatings were studied on an electron microscope of Carl Zeiss EVO XVP 40 with an INCA Energy 350 (Oxford Instruments) X-ray Spectral Microanalysis. It is shown that the surface of the electric arc coating has a typical composite structure, in contrast to the steel, in which there are lamellae with different microhardness. The volumetric amount of oxides in coatings varies from 6 to 20%. depending on the amount and chemical composition of the doping elements. Analysis of the results shows that the maximum content of oxides in the coating is observed when added to the charge of ferrophosphorus, ferrochrome and ferrotitanium. The roughness of the sprayed non-polished coating decreases with increasing the pressure of the air jet cutting when spraying the coating on the steel base from Rz 85, at a pressure of 0.4 MPa, to Rz 55 - 0.65 MPa. It was established that with increasing air pressure, the size of the structural components of the surface of the coating decreases, while its wear resistance in the conditions of limiting lubrication increases.