In the smelting process of high manganese steel, the volatilization of manganese will be accompanied. In this article, the volatilization of manganese in high manganese steel was studied by simultaneous thermal analyzer. The results show that the volatilization rate of manganese in high manganese steel increases with increasing temperature and holding time. It is proved by experimental study and data analysis that manganese volatilization follows the first-order kinetics model, and the empirical formula of manganese evaporation is derived. The volatile products of manganese were analyzed by scanning electron microscopy and X-ray photoelectron spectroscopy. It was found that the volatile components of manganese mainly consisted of MnO, Mn ₃ O ₄ , Mn ₂ O ₃ , and MnO ₂ . Combined with thermodynamics, the mechanism of manganese volatilization is further analyzed, and two forms of manganese volatilization in high manganese steel are revealed. One is that manganese atoms on the surface of high manganese steel and oxygen atoms in the gas form different types of manganese oxides and then volatilize at high temperature. The other way is that Mn atoms vaporize into Mn vapor and evaporate in high temperature environment, and then are oxidized into different types of manganese oxides. The results of theoretical calculation and experiment show that manganese volatilization is mainly in the first form.

The aluminum oxide inclusions in SWRS82B steel seriously affect the drawing performance of the steel strand. In this study, the influence of different additions of cerium (within the range of 0–0.034%) on the composition, morphology, size, number, and distribution of alumina inclusions was studied by scanning electron microscope and energy spectrum analyzer. The evolution of the composition of inclusions with different cerium additions was calculated based on classical thermodynamics and Factsage software calculation. The thermodynamic calculated results were consistent with the experimental results. It indicates that the modification route of Al₂O₃ inclusions in SWRS82B steel by increased cerium additions is as follows: Al₂O₃ → Ce₂S₃ + CeAlO₃ + Ce₂O₂S + Al₂O₃ → Ce₂S₃ + CeAlO₃ + Ce₂O₂S/Ce₂S₃ + Ce₂O₂S → Ce₂S₃ + Ce₂O₂S. Besides, when the amount of cerium is in the range of 0.023% to 0.030%, CeAlO₃ inclusions gradually disappear. The best characteristics of inclusions in this study were obtained in experimental samples with cerium addition of 0.023%, in which the minimum size of inclusions is in the range of 3.52–4.84 μm and mostly uniform distribution. Finally, the mechanism on the modification by cerium was discussed based on the composition evolution of inclusion during solidification with Factsage calculation and experimental results. The compositions of inclusions were also analyzed based on the inclusion evolution model.

In this study, high-temperature tensile tests were carried out on a Gleeble-3500 thermal simulator under a strain rate of ε = 1 × 10⁻³ s⁻¹ in the temperature range of 600–1310 °C. The hot deformation process of Fe–15.3Mn–0.58C–2.3Al TWIP/TRIP at different temperatures was studied. In the whole tested temperature range, the reduction of area ranged from 47.3 to 89.4% and reached the maximum value of 89.4% at 1275 °C. Assuming that 60% reduction of area is relative ductility trough, the high-temperature ductility trough was from 1275 °C to the melting point temperature, the medium-temperature ductility trough was 1000–1250 °C, and the low-temperature ductility trough was around 600 °C. The phase transformation process of the steel was analyzed by Thermo-Calc thermodynamics software. It was found that ferrite transformation occurred at 646 °C, and the austenite was softened by a small amount of ferrite, resulting in the reduction of thermoplastic and formation of the low-temperature ductility trough. However, the small difference in thermoplasticity in the low-temperature ductility trough was attributed to the small amount of ferrite and the low transformation temperature of ferrite. The tensile fracture at different temperatures was characterized by means of optical microscopy and scanning electron microscopy. It was found that there were Al₂O₃, AlN, MnO, and MnS(Se) impurities in the fracture. The abnormal points of thermoplasticity showed that the inclusions had a significant effect on the high-temperature mechanical properties. The results of EBSD local orientation difference analysis showed that the temperature range with good plasticity was around 1275 °C. Under large deformation extent, the phase difference in the internal position of the grain was larger than that in the grain boundary. The defect density in the grain was large, and the high dislocation density was the main deformation mechanism in the high-temperature tensile process.

Thermal deformation has a significant influence on the microstructure of high-strength antiseismic steel. The effect of hot deformation on the microstructure of experimental steel was studied by the Gleeble-3800 thermal simulator. The microstructure of the steel was characterized by the metallographic microscope, microhardness, tensile test, field emission scanning electron microscope, electron backscatter diffraction, and high-resolution transmission electron microscope. The results show that the core microstructure of the test steel is composed of polygonal ferrite and lamellar pearlite. The test steel is mainly ductile fracture. Tensile strength and hardness increase with the decrease of temperature. At 650 °C isothermal temperature, the ferrite distribution was uniform, the average grain size was 7.78 μm, the grain size grade reached 11, the pearlite lamellar spacing was 0.208 μm, and the tensile fracture was distributed with uniform equiaxed dimples. Polygonal ferrite grain boundaries have high density dislocations that can effectively block the initiation and propagation of cracks. However, there are some low dislocation boundaries and subgrain boundaries in ferrite grains. Precipitation strengthening is mainly provided by fine precipitates of V-rich carbonitride in experimental steel. The precipitates are round or narrow strips, about 70–100 nm in size, distributed along ferrite grain boundaries and matrix.