Analysis of the reasons for the formation of defects in the 12-Cr18-Ni10-Ti steel billets and development of recommendations for its elimination

OBRABOTKAMETALLOV Vol. 25 No. 1 2023 technology Results and Discussion The effect of the various components content on the formation of intergranular corrosion in stainless steel To identify the features of the intergranular corrosion development, stainless steel specimens were investigated according to the method described above. The presence of defects for various chemical compositions is noticed. Thermodynamic simulation was carried out for each composition — the quantity and the thermal nature of the forming carbide and nitride phases are estimated: titanium carbonitrides TiCxNy and Cr23C6 carbides. The relationship between the increased amount of chromium carbides and the defects of stainless steel is found and confirmed. Then temperature dependences of phase components in a wide range of various steel 12-Cr18Ni10-Ti components were calculated (for the initial composition taken: C = 0.08 %, Cr = 18 %, Ni = 10 %, Mn = 1.5 %, Ti = 0.4 %). The most significant elements are carbon and nitrogen. Figure 1 shows the typical thermal nature of the carbide and nitride phases in the stainless steel for the range of nitrogen changes N = 0.05–0.10 %. Fig. 1. Dependence of the content of chromium carbides Cr23C6 and titanium carbonitrides TiCxNy on the nitrogen content in steel: a – [N] = 0.05 %; б – [N] = 0.10 % а b

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