Using In Situ Observation to Reveal the Targeted Effect of Electric Current and to Clarify the Mechanism of Rapid Elimination of Network Carbides in Hot‐Rolled GCr15 Bearing Steel

The presence of coarse network carbides and lamellar cementite seriously reduces the material properties of hot‐rolled bearing steel. Due to the fact that network carbides are more difficult to dissolve under heat treatment, they become a key factor hindering the regulation of carbides in hot‐rolled bearing steel. Therefore, this study innovatively uses electric current treatment to effectively regulate the network carbides in bearing steel. In situ observation shows that electric current treatment promotes the dissolution of network carbides as a priority target. This phenomenon may be due to the difference in electrical properties between the grain boundary and the matrix, resulting in an increase in temperature and current density at the grain boundary. In addition, molecular dynamics simulations also indicate that the electric field reduces the diffusion activation energy of carbon atoms, thereby accelerating the dissolution of carbides. This work proposes a new strategy for controlling network carbides in bearing steel and provides direct evidence for the target effect of current.