In- situ observation of liquid zinc-induced erosion behavior diffusion mechanism in zinc-coated 22MnB5 steel

摘要

In this study, the erosion of liquid zinc penetrating 22MnB5 steel during austenitization was investigated by anin situmethod. High-temperature confocal laser scanning microscopy (HT-CLSM) results show that erosion occurred in several areas after melting of the galvanized coating. Meanwhile, the morphology of the erosion tip at the substrate side was transformed from a cutting edge into a flat shape with increasing temperature. In addition, an inhibiting layer was presented on the substrate after the galvanizing coating melted; the inhibiting layer disappeared with further temperature increases. The erosion sample of liquid zinc penetrating the 22MnB5 substrate at different dwell times was captured by an austenitization experiment. The results show that the erosion occurred after the rupture of the Fe2Al5inhibiting layer; in addition, the inhibiting layer found in the HT-CLSM experiment was shown to be Fe2Al5. Finally, the diffusion coefficient of zinc in α-Fe and γ-Fe at different temperatures was obtained by dynamic calculation based on zinc concentration; the results show that the relationship of zinc in α-Fe and γ-Fe is nonlinear and linear, respectively.