钢铁钒钛

2025 China’s titanium industry development report

AN Zhongsheng, ZHAO Wei, ZHOU Dawei

2026, 47(4): 1-8. doi: 10.7513/j.issn.1004-7638.2026.04.001

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Based on the full industry chain data of China’s titanium sector in 2025, this study systematically analyzed the production capacity, output, applications, and import-export dynamics of key products including titanium concentrate, sponge titanium, titanium ingots, and titanium materials. It summarized the industry development characteristics, identified core contractions, and proposed targeted recommendations, providing references for industrial optimization and upgrading.

Research progress on preparation methods and hot forming of TiAl alloy ingots

ZHANG Zhaoqun, TIAN Jing, ZHOU Feng, WANG Xin, CHEN Yuyong, JIANG Sida

2026, 47(4): 9-20, 42. doi: 10.7513/j.issn.1004-7638.2026.04.002

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TiAl alloys feature low density and high specific strength in the 600-900 ℃ temperature range and have been implemented in aero-engine components such as low pressure turbine blades. However, restricted by factors such as lacked room temperature ductility, a narrow hot working window, and strong sensitivity to solidification segregation and defects, the stable production of large scale ingots remains a key bottleneck for wider engineering application. This paper reviews the evolution of composition design in TiAl alloy systems and compares the characteristics, advantages, and limitations of typical ingot preparation routes including vacuum arc remelting, induction skull melting, vacuum induction melting, and plasma arc melting. Emphasis is placed on composition uniformity, inclusion and defect control at large ingot sizes, as well as the role of hybrid melting routes in improving quality stability. In addition, the critical roles of subsequent thermomechanical processing such as forging, extrusion, and rolling in densification, microstructure refinement, and property enhancement are summarized, providing references for process optimization and scalable manufacturing of large TiAl ingots.

The influence of Ti content and temperature on the mechanical behavior of FeNiCrCoTi_x high-entropy alloys under tensile and compressive loads: A molecular dynamics simulation study

BAI Peikang, ZHANG Jing, LI Jing, BAI Jiaming, WANG Mengxuan, WANG Zhuoqun

2026, 47(4): 21-34. doi: 10.7513/j.issn.1004-7638.2026.04.003

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Extensive investigations have been conducted currently into the mechanical properties of high-entropy alloys (HEAs), such as FeNiCrCoAl、FeNiCrCoCu、FeNiCrCoMn, etc. While the HEAs doped with Ti element are still lack of systematic research. In this field, the compressive mechanical behavior and intrinsic mechanism in atomic scale of FeNiCrCoTi HEAs have attracted increasing attention. Molecular dynamics (MD) simulations were used to comprehensively investigate how titanium content (4%~10%) and temperature (100~500 K) affect the FeNiCrCoTi_x HEA’s tensile and compressive mechanical properties. The findings highlight a tension–compression asymmetry in the mechanical response of HEAs. Among the different Ti contents, the T3 (x = 0.3) model exhibits the best performance, which is linked to the highest dislocation density, facilitating dislocation entanglement and accumulation, thereby enhancing tensile strength. In contrast, under compressive loading, the C2 model (x = 0.2) demonstrates optimal performance. This phenomenon is attributed to the formation of dislocation network by high-density dislocations within the C2, which contributes to its highest compressive strength. Both tensile and compressive strengths of the HEAs exhibit a monotonic decrease as temperature rises, which is attributed to the intensified atomic thermal motion with increasing temperatures, weakening grain boundary resistance and facilitating dislocation motion across lattice barriers, thus softening the materials at elevated temperatures. Collectively, this investigation offers critical insights into the mechanical behavior of FeNiCrCoTi HEAs and provides a theoretical basis for material applications via Ti content and temperature control.

Effect of holding time on the microstructure and mechanical properties of TC11 framework reinforced WE43 matrix composites

YANG Mingyang, HAN Shengli, GAO Pengfei, LUO Tiegang, CAO Peng, ZHENG Kaihong, PAN Fusheng

2026, 47(4): 35-42. doi: 10.7513/j.issn.1004-7638.2026.04.004

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This study designed a three-dimensional interconnected TC11 alloy framework as a reinforcement and prepared WE43-based composites using powder metallurgy combined with pressureless infiltration technology. Microstructural analysis shows that the TC11 framework reinforcement within the composite is continuously and uniformly distributed, and the pore regions inside the framework are fully filled with the WE43 matrix, forming a stable three-dimensional interpenetrating structure of TC11/WE43. At the same time at the interface of the composite material, a nanoscale Al₂Y transitional layer is formed through diffusion reaction, which enhances the interfacial strength. Mechanical performance test results indicate that when the holding time is 30 minutes, the TC11/WE43 composite material exhibits the best overall mechanical properties, with a yield strength (YS), ultimate tensile strength (UTS), and elongation (EL) of 417 MPa, 438 MPa, and 6.6%, respectively. The improvement in strength is attributed to the load transfer effect of the highly biomimetic TC11 framework and the excellent interfacial bonding strength.

Effect of heat treatment on the microstructure and mechanical properties of Ti₂AlNb alloys

MU Yiqiang, XU Rui, CHENG Chao, YU shuai, LIU yujing, XU Qinsi, ZHAO Zibo

2026, 47(4): 43-50, 65. doi: 10.7513/j.issn.1004-7638.2026.04.005

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This study proposed a duplex solution and aging heat treatment strategy. The volume fraction of the α₂ phase was tailored by controlling the primary solution-treatment temperature, while localized recrystallization was simultaneously suppressed. The secondary solution treatment promoted the precipitation of coarse lamellar O phase along subgrain boundaries, thereby improving the plastic deformability of the alloy. Subsequent aging induced a high density of fine acicular O-phase precipitates, which further enhanced the alloy strength. Through this heat-treatment route, a trimodal microstructure consisting of equiaxed α₂ grains and dual-scale lamellar O phases was obtained. The treated alloy exhibited a room-temperature elongation of 7.5% and a tensile strength of 837 MPa at 750 ℃, demonstrating a synergistic improvement in strength and ductility.

Microstructure, segregation and oxidation mechanism of AlV55 alloy prepared by aluminothermy

HE Zhimin, ZHANG Qi, ZHANG Yang, LI Xiaodong

2026, 47(4): 51-57. doi: 10.7513/j.issn.1004-7638.2026.04.006

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Using vanadium pentoxide and aluminum powder as raw materials, AlV55 vanadium-aluminum alloy was fabricated via the thermite reaction method. The macroscopic stratification, microstructure, elemental distribution and impurity behavior of the alloy ingot were systematically investigated. The results show that distinct upper and lower stratification occurs in the alloy ingot after the thermite reaction. The upper layer features loose microstructure, internal pores and alumina inclusions, with low and highly fluctuating vanadium content. Meanwhile, the lower layer possesses dense microstructure, strong metallic luster, high and uniformly distributed vanadium content. Microscopically, needle-shaped vanadium-aluminum solid solution is formed in the upper layer, while fishbone-shaped vanadium-aluminum solid solution dominates the lower layer. Composition segregation is caused by the coupled effect of diffusion rate difference and density disparity between vanadium and aluminum. The vanadium content is approximately 51.76 wt% in the upper layer and 58.87 wt% in the lower layer. The contents of impurities including oxygen, nitrogen, iron and silicon in the upper layer are remarkably higher than those in the lower layer. Analysis on the oxide layers of the alloy indicates that the binding energy (EB) of V 2p characteristic peaks varies with different colored oxide layers, and higher vanadium valence corresponds to larger binding energy. This study reveals the structural inhomogeneity and oxidation coloration mechanism of vanadium-aluminum alloys prepared by thermite reaction, and provides a theoretical basis for process optimization and high-quality fabrication of vanadium-aluminum alloys.

Differences in microstructure and impurity content among vanadium–aluminum alloys of various grades

ZHANG Qi, YAO Zhengwu, MA Zhilong, HE Zhimin, CHEN Yanxiong, NI Hangxing

2026, 47(4): 58-65. doi: 10.7513/j.issn.1004-7638.2026.04.007

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Titanium alloys are extensively utilized in the aerospace, automotive, and biomedical sectors. Vanadium–aluminum master alloys are key materials for preparing titanium alloys. In this study vanadium–aluminum master alloys of three grades such as AlV55, AlV65, and AlV85 were synthesized via aluminothermic route under identical raw-material inputs while varying stoichiometric ratios. The resulting ingots were characterized with respect to microstructures, impurity inventory, and mechanical response. The results show that AlV55 exhibits the lowest bulk-impurity level; however, its microstructure contains micro-cracks and gas-induced porosity. Phase analysis reveals Al₈V₅ intermetallic and a V-rich solid solution, the former conferring elevated hardness and wear resistance. AlV85, although showing higher tramp-element contents, displays superior inter-ingot consistency; the sole presence of the AlV₃ phase yields reduced hardness and inferior wear performance. AlV65 delivers the most balanced property profile, combining moderate impurity content with advantageous mechanical properties.

Sn²⁺ bridging enhanced oxidation stability of polyether solid-state electrolyte for stable sodium metal batteries

LI Xiaoyu, ZHANG Hongkun, HOU Minjie, ZHOU Huangkai, LIANG Feng

2026, 47(4): 66-76. doi: 10.7513/j.issn.1004-7638.2026.04.008

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Polyether-based solid-state electrolytes suffer from an intrinsically narrow electrochemical oxidation window that limits their compatibility with high-voltage cathode materials, while sodium metal anodes face the challenges of uncontrollable dendrite growth and continuous rupture-reconstruction of the solid electrolyte interphase (SEI) during cycling. These two issues jointly hinder the practical application of solid-state sodium metal batteries. In this work, an "ion-bridging" design strategy is proposed, in which tin(II) trifluoromethanesulfonate (Sn(OTf)₂) serves as a Lewis acid initiator to trigger the in situ ring-opening polymerization of 1,3-dioxolane (DOL) combined with cellulose triacetate (CTA), constructing a SnPDOL-CTA dual-network solid-state electrolyte. Using a metal-ion-free tris(pentafluorophenyl)borane (B(C₆F₅)₃)-initiated system as the control, we systematically analyzed the polymer structure, thermal properties, ionic transport, and electrochemical stability of the electrolyte, together with the deposition morphology and SEI chemical composition at the sodium metal anode. This comparison reveals the synergistic modulation mechanism of the Sn²⁺ ion-bridging structure in electrolyte performance and anode interfacial stability. Sn²⁺ coordinates simultaneously with the ether oxygen functional groups in both the PDOL chains and the CTA backbone, forming a dual-network crosslinked structure that lowers the highest occupied molecular orbital (HOMO) energy level of the system from −7.96 eV to −13.01 eV, expanding the electrochemical stability window beyond 4.5 V. The SnPDOL-CTA electrolyte exhibits a room-temperature ionic conductivity of 3.35×10⁻⁴ S·cm⁻¹ and a Na+ transference number of 0.64. Na||Na symmetric cells achieve stable cycling for over 1100 h with a critical current density of 1.1 mA·cm⁻². Sn²⁺ is in-situ reduced on the sodium metal anode surface, forming an organic-inorganic composite SEI layer rich in NaF and Na-Sn alloys, which effectively guides dense sodium deposition and suppresses dendrite growth. The half cells assembled with Na₃V₂(PO₄)₃ and Na₃V₂(PO₄)₂F₃ cathodes both deliver good cycling stability and rate capability.

Effect of heat treatment duration on microstructure evolution and electrochemical degradation behavior of electrodeposited Fe-4.8Zn alloy

WANG Jiawen, WANG Weiqiang

2026, 47(4): 77-84. doi: 10.7513/j.issn.1004-7638.2026.04.009

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Fe-4.8Zn alloy prepared by pulse electrodeposition was heat-treated at 450 ℃ for different holding times. The effects of heat treatment duration on the microstructure, phase composition, elemental distribution, microhardness, and electrochemical degradation behavior of the alloy were systematically studied. The results showed that heat treatment improved the recovery, rearrangement and homogenization of the microstructure on the surface and cross-section of the alloy. XRD analysis indicated that all samples were mainly composed of the α-Fe solid solution, and the diffraction peaks shifted slightly toward higher angles after heat treatment. The distributions of Fe and Zn were uniform, and no obvious elemental redistribution was observed. With increasing holding time, the microhardness of the alloy gradually increased, the corrosion potential shifted positively, the corrosion current density and corrosion rate decreased continuously, and the charge transfer resistance increased progressively. These results indicate that heat treatment duration has a significant effect on the microstructure, mechanical properties, and electrochemical degradation behavior of Fe-4.8Zn alloy, which provides an experimental support for the heat-treatment optimization of Fe-Zn alloys for biodegradable vascular stent applications.

Experimental study on deep denitrogenation of molten steel via vacuum coupled with carbon-oxygen reaction

WU Huajie, LIU Zuoyu, SUN Yue, ZHANG Ke, HUO Jiaxing, XU Jialong

2026, 47(4): 85-91, 108. doi: 10.7513/j.issn.1004-7638.2026.04.010

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Excessively high nitrogen content in steel significantly deteriorates its mechanical properties and subsequent processing performance. Achieving stable and efficient deep denitrogenation is a key technical challenge in producing high-quality steel during the converter and electric arc furnace steelmaking processes. This study, utilizing experiments in a 10 kg vacuum induction furnace, proposes and validates a method to enhance deep denitrification in molten steel by coupling carbon-oxygen reactions to generate endogenous CO bubbles under vacuum conditions. The effects of carbon-oxygen reaction intensity and initial nitrogen content on the denitrification behavior were systematically investigated and analyzed from both thermodynamic and kinetic perspectives. The results indicate that under vacuum conditions, the endogenous CO bubbles generated by the carbon-oxygen reaction significantly increase the gas-liquid reaction interface, thereby greatly enhancing the denitrification efficiency. As the intensity of the carbon-oxygen reaction increases, the denitrification rate of the molten steel accelerates markedly. With an initial carbon content of 1500×10^-6, the nitrogen content in the steel can be reduced to below 10×10^-6 within 10 minutes. Under the same carbon-oxygen reaction intensity, the initial nitrogen content does not significantly affect the denitrification rate but plays a decisive role in determining the final nitrogen content. Thermodynamic calculations show that the minimum nitrogen content achieved in the experiments is close to the equilibrium solubility under a vacuum of 30 Pa. Kinetic analysis reveals that the denitrification process is controlled by a mixed mechanism involving liquid-phase mass transfer and interfacial chemical reactions. A quantitative relationship was established at the experimental scale, showing that the denitrification rate is proportional to the 2/3 power of the decarburization rate. The study also found that in the ultra-low nitrogen range, as the carbon-oxygen reaction weakens, the molten steel's behavior can easily shift from denitrification to nitrogen absorption, necessitating strict control of vacuum conditions during the later stages of denitrification. The findings of this paper provide a theoretical basis and experimental reference for optimizing deep denitrification processes in vacuum refining processes.

Effect of tempering treatment on the microstructure and impact-corrosion-wear behavior of high chromium cast iron

CHEN Rongqin, SUN Xiao, WANG Shuai, LI Jinwei, ARTUR Pokrovsky, ZHENG Zhibin, LONG Jun

2026, 47(4): 92-99. doi: 10.7513/j.issn.1004-7638.2026.04.011

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In this study, high chromium cast iron was subjected to tempering treatment at different temperatures. The effects of tempering temperature on its microstructure, mechanical properties, and impact corrosion-wear behavior were investigated using OM, SEM, EDS, as well as property tests of hardness, impact toughness and impact-corrosion-wear tests. The results show that the tempered microstructure of high chromium cast iron mainly consists of eutectic carbides, tempered martensite, and secondary carbides. As the tempering temperature increases, the network eutectic carbides undergo reorganization, the characteristic of acicular martensite in the matrix weakens, and the matrix gradually transforms into tempered troostite and tempered sorbite. After low-temperature tempering (≤320 ℃), the hardness(HRC) remains above 60, whereas after high-temperature tempering at 550 ℃, the hardness(HRC) significantly decreases to 48.09. The tempering temperature has a minor effect on impact toughness, and the material still exhibits predominantly brittle fracture characteristics. When tempered below 450 ℃, the mass loss rate under different impact loads remains stable within the range of 21.6-26.2 mg/h. However, when the tempering temperature rises to 550 ℃, the mass loss rate significantly increases to 34.8-38.4 mg/h, indicating a sharp deterioration in the impact-corrosion-wear resistance.

The influence of heating process on the microstructure and properties of 700 MPa grade automobile beam steel

XU Zhen, TIAN Zhiwen, FENG Xiaoyong, ZHANG Fucheng

2026, 47(4): 100-108. doi: 10.7513/j.issn.1004-7638.2026.04.012

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In this study the effects of heating temperature and soaking time on the microstructure and properties of Ti-microalloyed automotive beam steel 700L had been investigated. Optical Microscopy (OM), Transmission Electron Microscopy (TEM), and Electron Backscatter Diffraction (EBSD) had been used to analyze microstructural changes in Ti-microalloyed automotive beam steel 700L under different heating processes. Theoretical calculations had been conducted by using a Thermo-Calc thermodynamic simulation software to analyze the precipitation behavior of the second phase, combined with EDS spectral analysis to examine the morphology and size of the second phase precipitates. Finally, Vickers hardness (HV) testing evaluated the comprehensive mechanical properties of the specimens. Results indicate that heating temperatures between 1230-1260 ℃ suppress primary austenite grain growth, yielding fine-grain strengthening with hardness (HV) ranging from 315 to 332. With soaking at 1290 ℃, abnormal grain coarsening occurs alongside large (2 μm) TiN particles. Extending the holding time from 80 min to 160 min, austenite grain coarsening became pronounced, hardness (HV) decreased from 282 to 251, and the mechanical properties of the test steel deteriorated.

Creep damage evaluation and remaining life prediction method for 12Cr1MoV steel based on high-temperature pneumatic bulging test

WANG Bumei, XIE Yi, GE Zhiqiang, ZHANG Tao, MA Xin

2026, 47(4): 109-116. doi: 10.7513/j.issn.1004-7638.2026.04.013

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Aiming at the problem of creep damage assessment for 12Cr1MoV steel used in the main steam pipeline of in-service power plants during long-term operation, a creep damage evaluation and remaining life prediction method based on micro-specimen high-temperature pneumatic bulging test is proposed. Creep interruption tests under different stress levels were carried out to obtain specimens with different damage states, and the residual mechanical properties of the material were tested by high-temperature pneumatic bulging technology via micro-specimens. Based on the obtained mechanical properties, creep damage evaluation parameters were constructed and coupled as internal variables to the Larson-Miller parameter model, and a prediction model for residual creep life was further established. The test results show that this method can effectively characterize the creep damage degree of the material, and the predicted residual life by the model is in good agreement with the tested results, with all predicted results within 1.5 times scatter band.

Effect of carbide distribution on microstructure and properties of NM500 grade wear-resistant steel

LI Zhengtao, XIONG Jincheng, ZHANG Hongbo, ZHOU Chun, LI Qiyuan

2026, 47(4): 117-124. doi: 10.7513/j.issn.1004-7638.2026.04.014

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Martensitic wear-resistant steel is widely used in metallurgy, building materials due to its excellent wear resistance. However, its insufficient toughness limits the service life of the material. To address this issue, a two-step tempering heat treatment after quenching was adopted to promote the precipitation of carbides within the martensitic laths. The results show that the two-step tempering reduces the proportion of carbides at grain boundaries from 45% after conventional tempering to 25%, leading to superior impact toughness and wear resistance compared to conventional tempering. Orthogonal experimental analysis and variance analysis reveal that the temperature and duration of the first tempering step exert significant effects on impact toughness and hardness, respectively. The optimal two-step tempering process is identified as tempering at 130 ℃ for 45 minutes followed by 200 ℃ for 45 minutes. Compared with conventional tempering at 200 ℃ , this process improves impact energy and wear resistance by 20% and 42%, respectively.

Effect of tempering temperature on the microstructure and low-temperature impact toughness of vanadium-contained X80 pipeline steel

ZHANG Yang, LI Longfei, WANG Chunhui

2026, 47(4): 125-134. doi: 10.7513/j.issn.1004-7638.2026.04.015

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In this paper, in order to clarify the influence of tempering temperature after thermo-mechanical control process on the low-temperature impact toughness of vanadium-contained X80 pipeline steel, the microstructural variation including nano-scale precipitates, microstructure, grain boundaries, and crystallographic characteristics, in experimental steels processed under six different tempering temperatures were investigated by multiple microstructural characterization methods. Furthermore, the relationship between the steel microstructures and low-temperature impact toughness was revealed. The results showed that with increasing tempering temperature from 450 ℃ to 650 ℃, the size and number of nano-scale precipitates in steel increased, while the size and quantity of granular acicular/lath ferrite and bainite decreased. Under these conditions, the low-temperature impact toughness was primarily dominated by the size and quantity of precipitates, exhibiting a gradually decreasing trend. Meanwhile, the number of polygonal ferrite increased and the ratio of high angle grain boundaries decreased. These microstructural changes led to a gradual decrease in low-temperature impact toughness. However, as the tempering temperature increased to 700 ℃, the ratio of fine precipitates in steel decreased and the average size increased. Moreover, the microstructure composed of coarse polygonal ferrite, with a significant increase in the ratio of high angle grain boundaries and Σ3 grain boundaries. Under tempering treatment at 700 ℃, the structural characteristics of grain boundaries were the main factors influencing low-temperature impact toughness. The impact energy of the steel tempered at 700 ℃ has been greatly improved, reaching up to 307.28 J.

Study on regulation of carbide precipitation behavior in GH4141 superalloy

GUO Jiarong, MA Hechuan, XIAO Dongping, ZHOU Yang, ZHANG Hongkai

2026, 47(4): 135-142. doi: 10.7513/j.issn.1004-7638.2026.04.016

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In this study the effects of heat treatment parameters including solution treatment temperatures (1 080-1 190℃), aging temperatures (850-950℃), and aging durations (20-60 min) on the carbide precipitation behavior and the regulation of grain boundary precipitation characteristics in GH4141 superalloy had been investigated. The results indicate that solution temperature is the key factor influencing the carbide precipitation location. Solution treatment at 1 120 ℃ effectively promotes grain boundary segregation of alloy elements, inducing continuous precipitation of MC and M₆C carbides along grain boundaries. In contrast, solution treatment at 1 190 ℃ results in dispersed distribution of carbides within grains and at grain boundaries. During the aging process, aging at 900 ℃ facilitates the formation of stable carbide precipitation characteristics along grain boundaries; however, aging at 900 ℃ for more than 40 min induces synergistic segregation of Mo and Cr elements and the precipitation of coarse MC carbides. By combining the results from precipitation characteristic analysis and mechanical property testing, it is found out that the optimal heat treatment process is determined to be 1 120 ℃ solution (0.5 h) combined with 900 ℃ aging (1 h). This process enables tailoring of MC and M₆C carbides along grain boundaries, it is suitable for alloys with a wide range of grain sizes, and achieves the high strength, providing an important theoretical basis for the manufacturing of high-performance GH4141 superalloy.

Study on the effects of pouring speed and mold heating temperature on shrinkage cavity of superalloy induction ingot

TANG Pingmei, ZHOU Yang, BAI Jingfei, MEN Zhengxing, GAO Xi, ZHANG Xianguang

2026, 47(4): 143-150. doi: 10.7513/j.issn.1004-7638.2026.04.017

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Large-scale shrinkage cavity defects exist in superalloy induction ingots, which significantly affect the yield of the induction ingots, the operational stability of the subsequent remelting processes and the product quality. This paper analyzes the effects of two typical process parameters, namely pouring speed and mold heating temperature, on the depth of shrinkage cavities in induction ingots through numerical simulation. The results indicate that the depth of shrinkage cavities in induction ingots does not change regularly with increasing pouring speed. Since adjusting the pouring speed fails to alter the longitudinal temperature distribution and solidification sequence of the induction ingot during solidification. It is impossible to significantly reduce the depth of shrinkage cavities through optimization of this process parameter. Using mold heating can reduce the temperature difference of the mold and the induction ingot in the longitudinal direction during solidification, which to some extent improves the trend of longitudinal solidification of the induction ingot towards the opposite direction of sequential solidification. Using mold heating can significantly reduce the depth of shrinkage cavities in induction ingots.

Effect of final rolling temperature on microstructure and properties of 500 MPa grade vanadium microalloyed high-strength steel

HAN Chufei, DONG Yi, SHI Xiaoguang, SUN Chengqian, WANG Junxiong, LI Zhi, XU Haijian

2026, 47(4): 151-156. doi: 10.7513/j.issn.1004-7638.2026.04.018

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In this research, low C-Mn-V-Cr-Nb composite microalloyed steel with a yield strength of 500 MPa was designed to meet the requirements of lightweight and high-performance materials in fields such as automotive, shipbuilding, and energy transmission. The effects of different final rolling temperatures (FRT, 920, 870, 820℃and 770 ℃) on the precipitates, microstructural characteristics, strength and toughness of 500 MPa grade high-strength steel were investigated. The -40 ℃ CVN impact energy and room temperature tensile test were performed. The microstructural characterization of the 500 MPa grade microalloyed steels with different final rolling temperatures were observed by using optical microscopy (OM), transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The results showed that with FRTs decreasing, grain size of the steel gradually refines during rolling in the unrecrystallized austenite zone. The volume fraction of V-rich nano carbonitrides inside the grain show a trend of firstly increasing and then decreasing. At the same time, the microstructure gradually evolved from polygonal ferrite (PF) and a small amount of acicular ferrite (AF), granular bainite (GB) to quasi polygonal ferrite (QF), AF and GB. Both strength and −40 ℃impact toughness of the steel are improved. Taking into account performance requirements and shape control during the rolling process, the FRT of 820-870 ℃ can produce the performance which meets the technical requirements for steel used in engineering equipments.

Research status and prospects of titanium component enrichment in titanium-bearing blast furnace slag

LI Haoyu, DU Peipei, LI Chenhui, TIAN Zhiqiang, LONG Yue

2026, 47(4): 157-172. doi: 10.7513/j.issn.1004-7638.2026.04.019

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As a relatively high-energy-consumption and high-pollution industry, the steel industry's energy-saving and emission-reduction pathways are crucial for achieving the goal of sustainable development. The blast furnace slag generated from smelting vanadium-titanium magnetite contains a large amount of titanium components, which are difficult to treat and thus stockpiled in large quantities, causing serious environmental pollution and resource waste. Therefore, the efficient and clean utilization of titanium-containing blast furnace slag and the improvement of valuable component utilization are of great significance to the steel industry. This paper provides a comprehensive review of the enrichment technologies for titanium components in titanium-bearing blast furnace slag, including selective, hydrometallurgical, and pyrometallurgical enrichment processes. It also provides prospects for the electric furnace melting separation–photocatalytic pretreatment–microbial acid leaching method. Currently, the treatment and resource utilization of titanium-bearing blast furnace slag still face numerous challenges, with key priorities including breakthroughs in chlorine removal from chlorination process waste residues, reducing pollution and costs in acid–alkali processes, and promoting the development and application of green and clean technologies to achieve high-value utilization of titanium resources.

Numerical simulation on phase transformation characteristics during water quenching process of single slag particle

LI Chengbo, LOU Guofeng, FENG Pengbo, XIAO Yongli

2026, 47(4): 173-181. doi: 10.7513/j.issn.1004-7638.2026.04.020

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To clarify the phase transformation mechanism of molten slag during water quenching and optimize the process parameters, this paper investigates the phase transformation process of molten slag after contact with water. First, combining the characteristics of the vapor film formed at the moment when molten slag contacts water with the flow field properties, a molten slag model containing a vapor film was established. Then, taking a particle size of 3 mm, a water velocity of 5 m/s, and an initial temperature of 1300 ℃ as the basic working conditions, the changes in the temperature field, phase transformation process, and temperature differences at different positions of the molten slag were analyzed. On this basis, the effect of water velocity on the heat exchange process of molten slag was explored, as well as the heat transfer characteristics of molten slag with different particle sizes under the same water velocity. In addition, supplementary verification was conducted on the optimal water velocity for cooling molten slag with particle sizes of 4 mm and 5 mm. The results show that water velocity has a threshold effect on the heat exchange of molten slag; its influence tends to flatten out when the velocity exceeds 5 m/s. Molten slag with particle sizes of 4 mm and 5 mm cannot meet the cooling requirements at a water velocity of 5 m/s, while a water velocity of 10 m/s can achieve effective cooling. Finally, the optimal process scheme was determined. This study provides theoretical basis and data support for the parameter optimization of the molten slag water quenching process.

Influence mechanism of impurity ions on interfacial emulsification during gallium extraction from vanadium extraction converter sludge leaching solution

QIN Zhifeng, JIANG Yang, DU Ming, YANG Zhen, LIU Juan

2026, 47(4): 182-188. doi: 10.7513/j.issn.1004-7638.2026.04.021

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This study systematically investigates the influence mechanisms of impurity ions such as Fe³⁺, Si⁴⁺ and Al³⁺ on interfacial emulsification in the solvent extraction of gallium. Through factorial experiments combined with characterization techniques such as FT-IR and SEM-EDS, it was found that Fe³⁺ induces phase separation due to co-extraction into the organic phase, while Si⁴⁺ hydrolysis products, specifically SiO₂, form a stable three-dimensional network structure at the interface, which is identified as a key factor for emulsification. Based on Pickering emulsion theory, calculations reveal that SiO₂ particles exhibit the highest adhesion energy at the oil-water interface, demonstrating the strongest interfacial stabilization capability. This research provides theoretical insights and technical support for preventing and controlling emulsification during gallium extraction.

Influence of steel slag powder on the properties of engineered cementitious composites

GAO Jianrong, LI Wenyu, JIANG Yong

2026, 47(4): 189-196. doi: 10.7513/j.issn.1004-7638.2026.04.022

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Abstract:
Engineered cementitious composites (ECC) hold significant application value in structural repair and protection due to their ultra-high ductility, strain-hardening behavior, and excellent durability. To reduce cement consumption and explore alternative materials to fly ash, this study employed ultra-fine steel slag powder (SSP) to progressively replace fly ash in the preparation of polyvinyl alcohol (PVA) fiber-reinforced ECC. The variations in the mechanical properties, microstructure, and hydration characteristics of ECC were systematically investigated. The results indicate that with an increasing SSP replacement ratio, both the flexural and compressive strengths of ECC exhibited an initial increase followed by a subsequent decrease. Notably, the improvement in flexural strength was more significant, with a 38.5% increase observed at a 50% replacement rate compared to the control group. The uniaxial tensile performance was also markedly enhanced; at a 75% replacement rate, the tensile strength and ultimate tensile strain increased by 95.0% and 131.3%, respectively, accompanied by more pronounced multiple-cracking behavior. Microstructural analysis revealed that the micro-filling effect and nucleation role of SSP promoted the uniform formation of hydration products, thereby increasing matrix density and enhancing the fiber-matrix interfacial bond, which consequently improved the macroscopic mechanical performance and tensile ductility. XRD and TG-DSC analysis further confirmed that the incorporation of SSP increased the calcium hydroxide and chemically bound water content in the cementitious system, optimizing the hydration process. This study provides experimental evidence and technical references for the resource utilization of steel slag and the development of high-performance ECC.

Current Articles 2026, Volume 47, Issue 4

Current Articles
2026, Volume 47, Issue 4