Behavior of MgO • Al2O3 Based Inclusions in Alloy Steel During Refining Process

The transformation of MgO
• Al2O3 based inclusions in alloy steel during refining has been studied by industrial trials. Besides Factsage software is used to study the formation and modification of spinel inclusions in alloy steel using calcium treatment during refining process. The results show that the transformation sequence of inclusions is: MgO
• Al2O3→CaO-Al2O3-MgO complex inclusions→MgO
• Al2O3, and under present experimental condition, in order to avoid forming MgO
• Al2O3 inclusions the content of dissolved Ca in the molten steel has to reach 1×10−6. Also the results show that when more calcium was added to molten steel, the content of Al2O3 and MgO will be lower. Besides, increasing the content of CaO in the inclusions will increase even if the content of SiO2 changes little.