Model alloys were developed to investigate the interaction of Mn, Si, and C during hot rolling. The alloy samples prepared by the method of vacuum-sealed tube heat treatment exhibited unique microstructural features: surface reduced Fe layer, interface reduced Fe layer and internal oxidation layer. The experimental results revealed that scale reduction is mainly controlled by the effect of Si and decarburization behavior, as well as the contribution of Si is more significant. The competing reactions of decarburization substantially reduce the depth of internal oxidation of the alloy. Additionally, combination of Mn and Si greatly facilitated the process of internal oxidation, with Si playing a role in inducing the inward oxidation of Mn. These insights will contribute to a better understanding of hot rolling coiling process, especially the complex interactions of Mn, Si, and C. •Complex interactions of Mn, Si and C during hot rolling coiling process are revealed.•The transformation of the oxide scale to pure iron occurs first at the scales/substrate interface, mainly is controlled by the replacement reaction of Si as well as decarburization behavior.•Mn and Si have a mutually reinforcing effect on internal oxidation, especially the preferential nucleation of Si promotes the internal oxidation of Mn.