Slag Inclusion

a defect in metal intermediate and finished products made primarily by rolling or forging. Slag inclusions are elongated accumulations of nonmetallic inclusions, from several millimeters to several centimeters in length; they usually form in the metal during pouring. They are arranged in the direction of the predominant flow of the metal upon deformation (mainly, on the surface of the metal or in the adjacent layers). Slag inclusions are removed mechanically, for example, by chiseling, flame treatment, and other methods.