Research on Behavior and Origin of Non-metallic Inclusions of Bearing Steel in Refining Process

By the methods of optical microscopy and SEM,the transformation of non-metallic inclusions of bearing steel GCr15 has been studied,which was produced in a certain electric strove factory whose smelting process is EAF-LF-VD-CC.Results show that inclusions in LF procedure are mainly Al2O3 like cluster,ametabolic punctuate inclusions and sulfide.After procedure of VD,the amount of Al2O3 and ametabolic punctuate inclusions reduce sharply.Whereas the complicated inclusions with Ca,Mg,Al,S and so on,have a growth in some degree.No ametabolic punctuate inclusions have been found in the sample of finished steel.There are only a bit of small sized Al2O3,sulfide and complicated inclusions with Ca,Mg,Al,S,etc.Inclusions are less and less in the process of refining and the origin of inclusions has been certified.