Experimental and First‐Principles Study on the Effect of Cu Content on High Temperature Oxidation Behavior of Low Carbon Steel

Residual copper (Cu) in recycled steel scrap is difficult to remove and tends to accumulate, degrading the surface quality of steel products. To investigate the role of Cu in high‐temperature oxidation, the behavior of low‐carbon steels with varying Cu contents was examined at 1100 °C through a combination of experiments and first‐principles calculations. Oxidation kinetics were measured, and the morphology and structural evolution of the oxide layer were characterized using scanning electron microscopy and electron probe microanalysis. First‐principles calculations were employed to clarify the effect of Cu on oxygen adsorption at the atomic and electronic levels. The results indicate that the addition of Cu accelerates the oxidation of the steel, leading to increased surface topographical irregularity and structural discontinuities. As the Cu content increased, the amount and size of Cu‐enriched phases within the oxide layer and at the interface also increased significantly. In the initial oxidation stage, these Cu‐enriched phases were granularly dispersed at the interface. As oxidation proceeded, they evolved to form continuous segregated layers and eventually a network‐like structure. First‐principles calculations show that Cu doping lowers the adsorption energy of O 2 , which strengthens the adsorption capacity of the interface and accelerates the oxidation reaction. This study provides a basis for mitigating hot shortness in steel caused by Cu contamination in recycled scrap.