Nauka ta progres transportu (Feb 2020)
THE INFLUENCE OF THE CHEMICAL COMPOSITION OF WEAR-RESISTANT CAST IRON ON THE INTERPHASE DISTRIBUTION OF MN AFTER ANNEALING AT 690°C
Abstract
Purpose. The article is aimed to obtain the regression dependences of manganese distribution between carbides and the metal base on the content of pig iron C, Cr, Mn and Ni after annealing at 690°C. Methodology. To achieve this purpose cast iron containing 1.09… 3.91% С; 11.43… 25.57% Cr; 0.6… 5.4% Mn; 0.19… 3.01% Ni and 0.8… 1.2% Si have been studied. To obtain reliable results analytical analysis of publications, microstructural and local micro-X-ray spectral methods, mathematical statistics and regression analysis of the obtained dependences were used. Findings. Using the methods of mathematical statistics, regression dependences of the manganese distribution between the phases and the magnitude of its concentration in the metallic basis of high-chromium cast iron on the content of C, Cr, Mn, and Ni after annealing at 690°C were obtained. During annealing, manganese was redistributed by replacing its atoms with chromium atoms in carbides. The effect of chromium and nickel varied significantly according to the content of manganese in cast iron. The minimum values of the manganese distribution coefficient of 0.16 were observed at the minimum carbon and manganese content and the maximum amount of chromium and nickel. The maximum concentration of manganese in the basis of 5.79% was determined with the minimum content of carbon and nickel and the maximum content of chromium and manganese. This made it possible to determine the chemical compositions of cast iron, which provide the required content of manganese in the metal base after annealing at 690°C. Originality. The regression dependences of the manganese content in the base and the coefficient of its interphase distribution on the content in cast iron of C, Cr, Mn and Ni after annealing at 690°C were obtained. Practical value. The obtained dependences of manganese distribution between phases in high-chromium cast iron after annealing at 690°C can be used during the development of the new wear resistant cast irons in the system Fe-C-Cr-Mn-Ni for castings that require heat treatment.
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