Hot Deformation Behavior and Processing Maps of 0.3C–15Cr–1Mo–0.5N High Nitrogen Martensitic Stainless Steel

Hot deformation behavior of 0.3C–15Cr–1Mo–0.5N high nitrogen martensitic stainless steel (HNMSS) was investigated in the temperature range of 1173–1473 K and at strain rates of 0.001–10 s−1 using a Gleeble 3500 thermal–mechanical simulator. The true stress–strain curves of the studied HNMSS were measured and corrected to eliminate the effect of friction on the flow stress. The relationship between the flow stress and Zener–Hollomon parameter for the studied HNMSS was analyzed in the Arrhenius hyperbolic sine constitutive model by the law of Z=3.76×1015sinh0.004979σp7.5022\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$Z = 3.76 \times 10^{15} \sinh \left( {0.004979\sigma_{\text{p}} } \right)^{7.5022}$$\end{document}. The processing maps at different strains of the studied HNMSS were plotted, and its flow instability regions in hot working were also confirmed in combination with the microstructure examination. Moreover, the optimal hot deformation parameters of the studied HNMSS could be suggested at T = 1303–1423 K 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} = 5–10 s−1 or T = 1273–1473 K 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} = 0.005–0.04 s−1.