To deal with the problem of poor yield strength and hardness in the initial use of high-manganese austenitic steel, we investigated the alloying design, microstructure, precipitates, mechanical properties, and comprehensive strengthening mechanism of high-manganese austenitic steel through two novel heat-treatment processes, namely continuous heating process (CHP) and segmented heat preservation process (SHPP). In this work, austenitic Fe-0.9C-17Mn-0.8Si-2.0Cr-0.3Ni-0.5Cu-0.7Mo steels alloyed with Ti, V, and Nb were designed. The grain size of SHPP steels was smaller than that of CHP steels due to the smaller size of precipitates. The results of mechanical experiments showed that the yield strength and impact toughness of SHPP steel were obviously higher than those of CHP steel, but the Brinell hardness of CHP steel was higher than that of SHPP steel. The higher Brinell hardness and poorer impact toughness of CHP steel were mainly due to the larger-sized precipitates. Finally, solid-solution strengthening played the most effective role of increasing the yield and tensile strengths of the two steels.
The collaboration of precipitated particles and austenitic matrix plays a significant role in the overall wear performance of high‐manganese (high‐Mn) austenitic steels. The austenitic matrix cannot support micrometer‐sized precipitates because of its poor Young's modulus and hardness before work hardening, and the relative sliding of abrasive particles over the matrix may result in the precipitates detaching from the matrix and deteriorating the overall wear performance of the steels. Herein, a solid‐solution temperature of 1100 °C is applied to balance the size of the austenite grains and precipitates. Different volume fractions of submicrometer V2C are precipitated in the austenitic matrix by aging at different temperatures, and the volume fraction of submicrometer V2C precipitates increases with aging treatment temperature. When the aging temperatures are higher than 450 °C, Young's modulus and nanohardness of the austenitic matrix are significantly enhanced, and the overall Brinell hardness and strength of the specimens are also improved. The improvement in the mechanical properties of the matrix is mostly related to the precipitation strengthening of nanoscale precipitates, and the enhancement in the overall hardness of the steels is mainly related to a sufficient amount of precipitated submicrometer V2C particles in the austenitic matrix.
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