The role of sulfide growth on the segregation behavior of sulfur at the grain boundary in a high-nickel steel

The role of sulfide growth behavior on the sulfur segregation at the grain boundary was studied in high-nickel steel. The alloy shows recrystallization, grain growth, and M(Ca, Mn)S growth during the holding at 800-1100 & DEG;C after applying rapid heating of 50 & DEG;C/s. As the annealing temperature increases, faster grain refinement (recrystallization) of the matrix and the growth behavior of MS are confirmed by electron backscatter diffraction and electron probe X-ray microanalyzer analyses. The segregation behavior of sulfur at the grain boundary was analyzed using Auger electron spectroscopy. The kinetics of intergranular sulfur segregation after holding at 800 & DEG;C showed time-dependent enrichment behavior, but sulfur seemed to be less segregated time-dependently during annealing at 900-1100 & DEG;C. Based on McLean's theory, a semi-quantitative calculation on the grain boundary sulfur segregation was applied without considering the sulfur-scavenging of MS and with thinking about the sulfur-scavenging of MS. The calculated result considering the sulfur-scavenging of MS better explained the experimental tendency of the grain boundary sulfur segregation at 800 & DEG;C. However, the difference between both calculations was negligible at 900-1100 & DEG;C due to the critical contribution of grain refinement.