To solve the copper brittleness problem of copper-bearing steel, support the ferritic rolling process, and ensure the continuity of rolling across different phase regions, this study focused on copper-bearing steel with w(Cu) = 1.56%. Gleeble thermal simulation tests were conducted to investigate the deformation behavior of Cu-bearing steel, and a corresponding deformation resistance model was established; meanwhile, the precipitation characteristics of the second phase were characterized by high-resolution transmission electron microscopy (HRTEM). The results show that the deformation resistance of copper-bearing steel increases with decreasing temperature and increasing strain rate, and its deformation resistance–temperature curve shows a unique bimodal trend, where the inflection point at 840 °C is attributed to the austenite–ferrite phase transformation, and the inflection point at 920 °C is caused by the precipitation of B2-FeCu ordered nanoclusters. HRTEM observations confirm that these nanoclusters are metastable phases with a size of less than 5 nm, and their orientation relationship with the matrix is (011)B2//(011)α-Fe and 001B2//001α-Fe. The area fraction of B2-FeCu ordered nano-precipitates is in the range of 4.27% to 5.32%, which can reduce the lattice distortion of the matrix and thus decrease dislocation slip resistance. The segmented modified Zhou-Guan model has a coefficient of determination (R2) greater than 0.96 between the predicted and experimental values, which can accurately guide the optimization of low-temperature rolling process parameters for copper-bearing steel.
Wang et al. (Thu,) studied this question.