Continuously cast near net shape blanks have been widely used in industry owing to the benefit of producing items close to final shape. However, for complicated shaped blanks, such as I and H beams, using near net shape blanks is not enough to prevent unwanted mass flow and deformation during hot rolling. The strength of the rolled material, pre-existing defects, and hot rolling parameters all have a major influence on the final shape of the rolled beam. In this study, the shaping of a low carbon steel during the breakdown mill hot rolling process was investigated using finite element analysis. The geometry of the as cast beam blank, mill roll profiles and hot rolling pass schedule were modeled identically to that used during the production hot rolling operation. The results showed that the I-beam has more deformation in the flange than in the web for breakdown mill rolling. A small depression or waviness was found to develop along the beam flange during the simulation. A parametric study of the effect of the roll gap on mass flow and beam blank surface depressions was performed. It was observed that for a larger roll gap, the surface depression increased in size. In contrast, the depression was found to decrease with a smaller rolling gap due to greater mass flow. These results agreed with the industrial produced I-beam. It was also predicted that the presence of a pre-existing surface defect on the beam blank flange has a significant influence on final size of the depression.