| The deformation behavior of commercial austenitic stainless steels under hot rolling conditions was investigated by means of hot compression tests performed in the temperature range 900℃ to 1200℃. Based on the variation of dislocation density due to strain hardening and dynamic recovery during hot deformation, the high temperature flow stress was formulated as a function of strain and steady-state flow stress by employing a modified Laasraoui-Jonas` model. The strain rate and temperature dependence of the steady-state flow stress was analyzed by using Sellars-Tegart`s model. The resultant constitutive equation, which correlates the flow stress with strain rate, temperature and strain, fitted well with the measured stress-strain curves. Type 304N1 steel exhibited a lower dynamic recovery rate than Type 304 and 316L steels, which was attributed to the enhancec planar slip due to nitrogen addition. The temperature dependency of steady-state flow stress was found to increase in the order : Type 304, 316L, 304N1. |
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