Influence of calcium carbide slag additions on inclusion characteristics in steel

An investigation into the cleanness of steel manufactured by a major Scandi navian producer of steel for railway wheels has been carried out. Samples t aken before and after secondary refining in the ladle and after degassing w ere compared with samples taken similarly from a heat including the additio n of a calcium carbide (CaC2) slag modifier. The amount, size distribution, and composition of non-metallic inclusions, as well as the slag compositio ns of both heats, were determined. With the addition of CaC2, the total num ber of inclusions in the sample taken before casting was found to decrease, and the size distribution revealed the presence of mostly small inclusions (between 2.8 and 5.6 mum). The assessment of railway wheel specimens revea led that the inclusion content in CaC2 treated steel was lower than that fo r standard steel.