The influences of S and Ti contents as well as slab reheating temperature on the precipitation behavior of sulfides in hot-rolled bands in Ti-added ultra low-carbon steels have been investigated. The results obtained are as follows: In the specimens with the same 0.02%Ti content, Ti₄C₂S₂ decreases and TiS increases in number as S content increases while in the specimens with the same 0.008% S content, TiS decreases and Ti₄C₂S₂ increases in number as Ti content increases. The number of TiS increases when the slab reheating temperature is high.
The solubility prodects of TiS and Ti₄C₂S₂ in austenite have been also experimentally determined as follows:
log [Ti][S] = -3252/T-2.01
log [Ti][C]^0.5[S]^0.5 = -5208/T-0.78
The experimental results above agree well with the results calculated using these solubility products. The reliability of solubility products determined in this study are checked and it is confirmed that the solubility products in this study is in good agreement with the published experimental results.