Effect of Mn on Solubility of Ti-sulfide and Ti-carbosulfide in Ultra-low C Steels

Abstract

To clarify the thermodynamic stability of Ti₄C₂S₂ and TiS in ULC Ti-added IF steels, extraction by potentiostatic electrolysis method and chemical analysis were conducted with ULC Ti-added IF steels containing various amounts of Mn and heated at various temperatures. As the results, the solubilities of Ti₄C₂S₂ and TiS increased with an increase in Mn content. Ti₄C₂S₂ was more stable than TiS between 950 and 1250°C. Following solubility products were obtained.
log[Ti]·[C]^0.5·[S]^0.5=0.392−7004/T−(4.783−7401/T)·[Mn]
log[Ti]^2/3·[S]=−0.021−5847/T−(3.360−5195/T)·[Mn]