Influence of Si content on selective oxidation and oxide scale phase transition during hot-rolled coiling

The internal oxidation formed during the advanced high-strength steels hot-rolled coiling process can be inherited into the cold-rolled sheet and impact the final product quality. Herein, the influence of Si on the internal oxidation and oxide scale phase transition behavior of Fe-Mn-Si advanced high-strength steel after hot-rolled coiling are investigated. The results indicate that the internal oxidation depth increases with the increase of Si content and is accompanied by severe intragranular oxidation. Moreover, the interface between Mn-Si oxide and substrate provides a direct diffusion path, which accelerates the rate of internal oxidation. In addition, the displacement reaction of Si/Mn is the primary cause for the formation of continuous pure Fe at the interface of oxide scale/substrate.