Effect of Slag-Metal Reaction on Transformation of Al2O3 inclusions in Pipeline Steel
For high grade pipeline steel, elimination of Al2O3 inclusions can improve the susceptibility of hydrogen-induced cracking (HIC) and stress corrosion cracking (SCC). In the present work, the transformation of Al2O3 inclusions with slag-metal reaction was studied by controlling ladle slag and relative technologies in LF-RH refining process. It is found that Al2O3 inclusions decrease with increasing refining time, and no pure Al2O3 inclusions exist in molten steel at the end of secondary refining; the remained inclusions in molten steel are liquid calcium aluminates and semi-liquid CaO-MgO-Al2O3 complex inclusions. The analysis of thermodynamic equilibrium proves that CaO and MgO in slag can be reduced by aluminum in molten steel, which is the source of calcium and magnesium in molten steel.
Xiaoming Sang, Pengcheng Wang, Liqun Ai, Yungang Li and Jinglong Bu
Q. Li et al., "Effect of Slag-Metal Reaction on Transformation of Al2O3 inclusions in Pipeline Steel", Advanced Materials Research, Vols. 284-286, pp. 1143-1147, 2011