Thermoplastic Deformation of Ladle-Treated Hadfield Steel with Free Crack Susceptibility

Ladle treatment technology is expected to be a new approach for prevailing over the hot crack susceptibility of conventional high-manganese steel. The liquefaction and solidification mechanisms of the conventional and ladle-treated high-manganese steel were detected by DTA. Their solidification structures were observed by optical microscope and scanning electron microscope. Multistage deformation process of the two steels was carried out by using thermomechanical simulator (Bahr TTS-820) from 700 to 1200 °C. In addition, their thermoplastic character was detected by dilatometer (DIL-805/D) from 800 to 1200 °C. On the other hand, TEM was used for explaining the nucleation of cementite and austenite at magnesium sulfide nuclei in ladle-treated high-manganese steel. The results refer to the peculiar microstructure after ladle treatment of high-manganese steel causes a great enhancement in the hot forming character of high-manganese steel in terms of crack susceptibility and flow stress. In addition, the good formability of the ladle-treated high-manganese steel was confirmed by comparing with the low-carbon steel at hot working temperatures.