Abstract Elongated inclusions seriously affect the mechanical properties and isotropy of steels, and may also be regarded as causing a reduction of toughness in steels used for making pipes and a deterioration of the formability in hot-rolled steel sheets. The number of elongated inclusions after hot working can be reduced by current methods and, by adding elements such as calcium, zirconium, titanium, or rare earths, it is possible to increase the formability. The authors' aim is to predict, on the basis of chemical composition, the principal characteristics of the inclusion content of low-carbon steels.