High‐Temperature Tensile Properties and Deformation Behavior of Three As‐Cast High‐Manganese Steels

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Herein, the high‐temperature tensile properties and deformation behavior of three as‐cast high‐manganese steels with various carbon contents (0.028, 0.28, and 0.64 wt%) are investigated using a combination of hot tensile tests and isothermal hot compression on a Gleeble‐3500 thermomechanical simulator with different temperatures and strain rates. The results indicate that the carbon content increase makes a greater number of Mn–C dipoles available for a short‐range ordering and increases in the peak stress and the maximum flow stress at a constant test temperature and strain rate. In contrast, the stress decreases with increasing test temperatures. The change in carbon content affects the phase transformation at high temperatures, leading to differences in hot ductility. Steels with a carbon content of 0.028 and 0.28 wt% have similar hot brittle temperature ranges, whereas the ductility of the steel improves with increasing temperatures when the carbon content increases to 0.64 wt%. For the hot compression test, the influence of strain rates in increasing the maximum stress grows with increasing carbon content. The hot deformation activation energies of different steels are confirmed, with which the peak stresses could be predicted by the Z parameter in the hyperbolic sine equation. A good correlation is obtained between model predictions and experimental observations in the peak stress.