To study the influence of different deformation parameters of the hot working process on the microstructure of 20Cr2Ni4A gear steel during the plastic forming process, the heat deformation experiment of 20Cr2Ni4A gear steel was carried out using the Gleeble-3500 Thermal Machanical Simulator, and the heat deformation behavior of hot 20Cr2Ni4A gear steel under different deformation conditions was investigated. Through the dislocation density model, recrystallization nucleation and grain growth model, we innovatively wrote the cellular automaton program to simulate the dynamic recrystallization behavior during the heat deformation process. The simulation results were verified through EBSD and metallographic diagrams.
This paper studied the high-temperature stability of dissimilar steel welded joints between G115 and Sanicro25 steel. The joints were exposed to 700 C-degrees for time up to 2000h. The microstructure evolution of base metal (BM) and fine-grain heat-affected zone (FGHAZ) were analyzed. Tensile, microhardness, and impact experiments were conducted on the joints, and the explanations for the changes in mechanical performance are derived from the microstructure. The results showed that the Laves phase were precipitated after aging for 100 h, which has two nucleation methods. Nucleation adjacent to M23C6 is the main way in this research. Laves phase mainly grows up to consume M23C6. The microstructure in BM and FGHAZ is obviously different after aging. After aging for 1000 h, mechanical properties such as tensile strength, Vickers hardness, impact energy, elongation and area reduction are reduced, except for the yield strength. The softening caused by the microstructure evolution of FGHAZ is the main reason for the joint fracture in FGHAZ.
Effect of aging rolling on the microstructure,texture and magnetic properties of the low-temperature oriented silicon steel was studied by conducting aging rolling tests at 250 ℃ for different time using a single cold rolling method.The results indicate that the aging rolling has no significant effect on the cold rolling and primary recrystallization microstructure of low-temperature oriented silicon steel,but it can significantly improve the primary recrystallization texture.The contents of favorable Goss and { 111 }<112>textures in the primary recrystallization microstructure increase first and then decrease with the increase of aging rolling time,reaching the maximum value at 5 min.An increase in favorable texture content can improve the secondary recrystallization microstructure and enhance the magnetic properties of the final sheet.The magnetic induction intensity of the final sheet increases first and then decreases with the prolongation of aging rolling time,and the iron loss shows the opposite trend.When the aging rolling time is 3-7 min,the final sheet has excellent magnetic properties.
The reutilization of granite sludge generated in granite cutting and processing possesses economic and ecological benefits. In this study, high-strength glazed glass-ceramics were prepared entirely from granite powder using dense sintering and instantaneous glaze firing. The densification and glaze formation are clarified in terms of phase evolution to study their effects on the flexural strength and surface glossiness of the glass-ceramics. The milling process promotes particle refinement and the removal of colored minerals, thus increasing the powder whiteness and sinterability. After dense sintering at 1100 degrees C, instantaneous glaze firing at high temperatures decreases the flexural strength while greatly increases the surface glossiness of the glass-ceramics due to the dissolution of quartz and feldspars in the liquid phase. After the acid-leached powder was densely sintered and fired with a rapid heating of 50 degrees C/min to 1300 degrees C, the pinhole-free glazed glass-ceramic has a flexural strength of 112.5 MPa and a surface glossiness of 54.7 GU (glossiness unit), meeting the quality requirements of the bright glazed tiles in the market. The stepwise sintering process provides a simple processing route for recycling granite sludge into decorative construction tiles and high-temperature glazes, promising the scalable and value-added utilization of granite sludge.
The effects of Sc and/or excess Mg on the microstructure characteristics, tensile properties, and fracture behavior of a hypoeutectic Al-10Mg2Si alloy were systematically studied. The results showed that adding 0.25
