Hot Deformation Behavior and Processing Map of Cu-Bearing Ship Plate Steels

Cu-bearing steels are widely used in the shipbuilding and medical industries because of their excellent strength, corrosion resistance, and antibacterial properties. In this study, the instability behavior of ship plate steels with the Cu contents of 0.98 and 1.62% during hot deformation was studied through a hot compression deformation experiment. The hot processing maps of the Cu-bearing ship plate steels were constructed based on the dynamic material model and Prasad instability criterion. Then, the preparation process of the test steel was analyzed and predicted. Results showed that the hot working instability zone of the ship plate steels with different Cu contents decreased with the increase in strain, and the addition of the alloying element Cu can significantly increase the hot working instability zone of the ship plate steels. The optimal parameters for the hot deformation of the tested steels were obtained as follows: temperatures T(0.98% Cu) of 1323-1423 K and T(1.62% Cu) of 1323-1423 K and strain rates ε˙\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\dot{\varepsilon }$$\end{document}(0.98Cu) of 3-7 s−1 and ε˙\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\dot{\varepsilon }$$\end{document}(0.98Cu) of 0.01-0.1 s−1. The existence of an instability zone in the test steels during thermal deformation could be ascribed to the preferential segregation of Cu at the grain boundary during processing. Then, grain boundary cracking, which reduced the machinability of the ship plate steels, correspondingly occurred. The hot working construction of test steels can enable optimal control of the preparation process.