PECULIARITIES OF CRYSTALLOGRAPHIC PARAMETERS OF NANODISPERSED COMPOSITIONS AND THEIR IMPACT ON THE PROPERTIES OF LOW-ALLOYED STEEL

Annotation. Purpose. Investigation of the role of refractory nanoparticles with the necessary thermodynamic and crystallographic parameters and application of the data obtained to develop a method for surface modification of low-alloy structural steels. Methodology. The object of the study was cast casts of low-alloy steel 09G2S, modified with nanopowder compositions of carbide and carbonitride class based on Al, Ti, Si. Nanodispersed powders up to 100 nm in size were obtained by the method of plasma-chemical synthesis. Findings. To assess the modifying efficiency of refractory compositions, the data on the molar enthalpy of their formation, melting point, solubility in the melt, and conductivity type are summarized. Technological parameters of plasmachemical synthesis of nanopowders have been worked out. The granulometric composition was studied by X-ray diffraction analysis and electron microscopy. The optimal amount of modifier particles was determined by calculation: 0,08 ... 0,15% of the melt weight. On the surface of the cast samples, the depth of the layer impregnated with Ti(CN), TiC nanocomposites in various ratios was determined. Dependence of the impregnation depth on the temperature of the cast steel and the time of exposure of the melt is established. Originality. A mechanism is established for the interaction of a steel melt with a layer of nanodispersed composition, including heating the nanopowder layer on the surface of the casting, filtering the melt into the pores of the powder, diffusion processes in the distribution of particles in the liquid phase and in the cooling of the casting. Practical value. The carried out experiments to determine the wear resistance showed that the steel wear rate was the highest coefficient of wear resistance, which was impregnated with Ti (CN) nanodispersed powder.