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  Subjects -> ENVIRONMENTAL STUDIES (Total: 832 journals)
    - ENVIRONMENTAL STUDIES (758 journals)
    - POLLUTION (24 journals)
    - TOXICOLOGY AND ENVIRONMENTAL SAFETY (40 journals)
    - WASTE MANAGEMENT (10 journals)

ENVIRONMENTAL STUDIES (758 journals)            First | 1 2 3 4 5 6 7 8     

Harvard Environmental Law Review     Free   (Followers: 11)
Health Services Management Research     Hybrid Journal   (Followers: 12)
Health, Safety and Environment     Open Access   (Followers: 9)
Hereditas     Open Access   (Followers: 2)
Hidrobiológica     Open Access  
Historia Ambiental Latinoamericana y Caribeña     Open Access   (Followers: 1)
Home Health Care Management & Practice     Hybrid Journal   (Followers: 3)
Horticulture, Environment, and Biotechnology     Hybrid Journal   (Followers: 11)
Human & Experimental Toxicology     Hybrid Journal   (Followers: 6)
Human Ecology     Hybrid Journal   (Followers: 20)
Human Studies     Hybrid Journal   (Followers: 8)
Husserl Studies     Hybrid Journal  
Hydro Nepal : Journal of Water, Energy and Environment     Open Access   (Followers: 1)
Hydrology: Current Research     Open Access   (Followers: 10)
IAMURE International Journal of Ecology and Conservation     Open Access   (Followers: 5)
Ideas in Ecology and Evolution     Open Access   (Followers: 11)
IEEE Transactions on Network and Service Management     Hybrid Journal   (Followers: 13)
IMA Journal of Management Mathematics     Hybrid Journal   (Followers: 1)
Indiana Journal of Global Legal Studies     Full-text available via subscription   (Followers: 1)
Indoor Air     Hybrid Journal   (Followers: 2)
Information Systems Management     Hybrid Journal   (Followers: 17)
Information Technology and Management     Hybrid Journal   (Followers: 11)
Ingeniería Hidráulica y Ambiental     Open Access  
Inhalation Toxicology     Hybrid Journal   (Followers: 7)
Integrated Environmental Assessment and Management     Hybrid Journal   (Followers: 5)
Interdisciplinary Environmental Review     Hybrid Journal   (Followers: 3)
Interfaces     Full-text available via subscription   (Followers: 7)
International Aquatic Research     Open Access   (Followers: 4)
International Archives of Occupational and Environmental Health     Hybrid Journal   (Followers: 4)
International Environmental Agreements: Politics, Law and Economics     Hybrid Journal   (Followers: 11)
International Gambling Studies     Hybrid Journal   (Followers: 6)
International Innovation - climate     Open Access   (Followers: 1)
International innovation. Environment     Open Access  
International Journal of Acarology     Hybrid Journal   (Followers: 1)
International Journal of Advancement in Earth and Enviromental Sciences     Open Access   (Followers: 1)
International Journal of African Renaissance Studies - Multi-, Inter- and Transdisciplinarity     Hybrid Journal   (Followers: 2)
International Journal of Agricultural and Environmental Information Systems     Full-text available via subscription   (Followers: 3)
International Journal of Alternative Propulsion     Hybrid Journal   (Followers: 1)
International Journal of Applied Psychoanalytic Studies     Hybrid Journal   (Followers: 2)
International Journal of Chinese Culture and Management     Hybrid Journal   (Followers: 2)
International Journal of Corrosion     Open Access   (Followers: 13)
International Journal of Critical Infrastructures     Hybrid Journal   (Followers: 3)
International Journal of Disaster Risk Reduction     Hybrid Journal   (Followers: 7)
International Journal of Disaster Risk Science     Open Access   (Followers: 11)
International Journal of Ecological Economics and Statistics     Full-text available via subscription  
International Journal of Ecology     Open Access   (Followers: 8)
International Journal of Ecology & Development     Full-text available via subscription   (Followers: 2)
International Journal of Energy and Environmental Engineering     Open Access   (Followers: 2)
International Journal of Environment     Open Access   (Followers: 3)
International Journal of Environment and Health     Hybrid Journal   (Followers: 8)
International Journal of Environment and Pollution     Hybrid Journal   (Followers: 5)
International Journal of Environment and Sustainable Development     Hybrid Journal   (Followers: 17)
International Journal of Environment and Waste Management     Hybrid Journal   (Followers: 6)
International Journal of Environment, Workplace and Employment     Hybrid Journal   (Followers: 3)
International Journal of Environmental Engineering     Hybrid Journal   (Followers: 5)
International Journal of Environmental Health Research     Hybrid Journal   (Followers: 2)
International Journal of Environmental Policy and Decision Making     Hybrid Journal   (Followers: 10)
International Journal of Environmental Protection     Open Access   (Followers: 12)
International Journal of Environmental Research and Public Health     Open Access   (Followers: 18)
International Journal of Environmental Science and Technology     Hybrid Journal   (Followers: 5)
International Journal of Environmental Studies     Hybrid Journal   (Followers: 10)
International Journal of Exergy     Hybrid Journal   (Followers: 4)
International Journal of Forest, Soil and Erosion     Open Access   (Followers: 5)
International Journal of Global Environmental Issues     Hybrid Journal   (Followers: 4)
International Journal of Global Warming     Hybrid Journal   (Followers: 4)
International Journal of Greenhouse Gas Control     Partially Free   (Followers: 6)
International Journal of Health Planning and Management     Hybrid Journal   (Followers: 8)
International Journal of Hygiene and Environmental Health     Hybrid Journal   (Followers: 7)
International Journal of Logistics Research and Applications : A Leading Journal of Supply Chain Management     Hybrid Journal   (Followers: 10)
International Journal of Philosophical Studies     Hybrid Journal   (Followers: 2)
International Journal of Phytoremediation     Hybrid Journal   (Followers: 2)
International Journal of Process Systems Engineering     Hybrid Journal   (Followers: 1)
International Journal of Recycling of Organic Waste in Agriculture     Open Access   (Followers: 2)
International Journal of Reliability and Safety     Hybrid Journal   (Followers: 10)
International Journal of Renewable Energy Development     Open Access   (Followers: 6)
International Journal of Social Sciences and Management     Open Access   (Followers: 2)
International Journal of Soil, Sediment and Water     Open Access   (Followers: 7)
International Journal of Stress Management     Full-text available via subscription   (Followers: 11)
International Journal of Sustainable Construction Engineering and Technology     Open Access   (Followers: 11)
International Journal of Sustainable Engineering     Hybrid Journal   (Followers: 7)
International Journal of Sustainable Materials and Structural Systems     Hybrid Journal   (Followers: 5)
International Journal of Sustainable Society     Hybrid Journal   (Followers: 5)
International Journal of Testing     Hybrid Journal   (Followers: 2)
International Journal of the Commons     Open Access   (Followers: 2)
International Journal of Toxicology     Hybrid Journal   (Followers: 6)
International Journal of Water Resources and Environmental Engineering     Open Access   (Followers: 3)
International Studies in the Philosophy of Science     Hybrid Journal   (Followers: 13)
Interventions : International Journal of Postcolonial Studies     Hybrid Journal   (Followers: 12)
IOP Conference Series: Earth and Environmental Science     Open Access   (Followers: 6)
Iranian Studies     Hybrid Journal   (Followers: 10)
Irish Educational Studies     Hybrid Journal   (Followers: 2)
Irish Journal of Earth Sciences     Full-text available via subscription  
Irish Political Studies     Hybrid Journal   (Followers: 9)
ISLE: Interdisciplinary Studies in Literature and Environment     Hybrid Journal   (Followers: 1)
Isotopes in Environmental and Health Studies     Hybrid Journal   (Followers: 1)
Israel Studies     Full-text available via subscription   (Followers: 5)
Italian Studies     Hybrid Journal   (Followers: 6)
Jahangirnagar University Environmental Bulletin     Open Access  
Journal of Bioremediation & Biodegradation     Open Access   (Followers: 3)
Journal of Earth Science & Climatic Change     Open Access   (Followers: 8)

  First | 1 2 3 4 5 6 7 8     

Journal Cover Journal of Iron and Steel Research, International
  [SJR: 0.784]   [H-I: 16]   [8 followers]  Follow
    
   Full-text available via subscription Subscription journal
   ISSN (Print) 1006-706X
   Published by Elsevier Homepage  [2801 journals]
  • Fatigue Performance of Microalloyed High-strength Rebar and Analysis of
           Fracture Mechanism
    • Abstract: Publication date: December 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 12
      Author(s): Peng-yan LU, Yu LIU, Hua-jie WU, Gang LIU, Xiang MENG, Yang XU
      Fatigue performance of hot-rolled ribbed-steel bar with the yield strength of 500 MPa (HRB500) was studied with bend-rotating fatigue test at a stress ratio of R = −1. It is determined by staircase method that its fatigue strength for 107 cycles is 451 MPa, which is higher than that of common carbon structural steel. This should be attributed to the fine-grain strengthening resulting from the high content of alloy element V and Thermo-Mechanical Control Process (TMCP). The S-N curve function is also obtained by nonlinear regression with three parameters power function. The fatigue fractures of the specimen were further analyzed with Scanning Electron Microscopy (SEM) and Energy Disperse Spectroscopy (EDS) to study the fracture mechanism. Taking into account microstructure, hardness and cleanliness of the material, it implies that the fatigue fractures of HRB500 rebar all arise from surface substrates in which many brittle inclusions are contained, and that the fatigue crack propagation is principally based on the mechanism of quasi-cleavage fracture, because of the intracrystalline hard spots leading to stress concentration and thus to the cracks. Moreover, the transient breaking area exhibits microvoid coalescence of ductile fracture due to the existing abundant inclusions.


      PubDate: 2016-01-20T10:38:17Z
       
  • Passivation Behaviors of Super Martensitic Stainless Steel in Weak Acidic
           and Weak Alkaline NaCl Solutions
    • Abstract: Publication date: December 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 12
      Author(s): Jian KANG, Jun LI, Kun-yu ZHAO, Xuan BAI, Qi-long YONG, Jie SU
      The passivation behaviors of super martensitic stainless steels (SMSS) were studied by polarization curves at passive potential of −0. 1 V and in various NaCl solutions, electrochemical impedance spectroscopy (EIS) and X-ray photoelectron spectroscopy (XPS) analysis. Electrochemical test results showed that, in alkaline solutions, passivation region width was wider, passivation current was smaller, and polarization resistance was greater; thus, the passive film of SMSS in alkaline solutions had better passivation behaviors than that in acidic solutions. The polarization curve and EIS of samples SMSS1 and SMSS2 were also used to study which sample had better passivation behaviors. All results demonstrated that passive film structure of SMSS1 sample was more stable, and capacity of passive film was enhanced. The impact of alloying elements on the passive film (SMSS) passivation capability was also discussed by XPS depth profiling, and XPS depth profiling showed that the composition of the passive film was mainly composed of Fe-oxide and Cr-oxide. So the passive film structures were mixed layers of Fe-oxide and Cr-oxide. Fe oxidation product and Cr oxidation product would help to improve the protective property of passive film, which could promote the formation of a passive film structure more stably and densely.


      PubDate: 2016-01-20T10:38:17Z
       
  • Newly Designed Cr-Mn Alloyed Ultra-high Strength Steel without Boron
           Addition for Hot-stamping Processing
    • Abstract: Publication date: December 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 12
      Author(s): Guo-hui ZHU, Hong-bing ZHOU, Qin-yi LI, Qi-wei CHEN, Hai-rong GU, Yong-gang LIU
      A newly designed hot-stamping steel alloyed by chromium (Cr) and manganese (Mn) without boron (B) addition was developed for automobile mass reduction. The experimental results showed the Cr-Mn alloyed steel could be quenched to full martensite microstructure when the cooling rate was higher than 14 °C/s. Yield strength, tensile strength and elongation of the experimental hot stamping part reached 1180 MPa, 1645 MPa and 8.4%, respectively. The experimental hot stamping part possessed higher tensile strength and elongation, compared with conventional hot-stamping steel of 22MnB5. Furthermore, excellent processing flexibility would be obtained in this novel hot-stamping steel because of its lower critical cooling rate and phase transformation temperature. The design of the composition and investigations of microstructure, mechanical properties and hot-stamping processing were also studied.


      PubDate: 2016-01-20T10:38:17Z
       
  • Effects of Pulsed Current and Pulsed Magnetic Field Complex Pretreatment
           on Martensite Transformation of Cr5 Steel during Continuous Cooling
    • Abstract: Publication date: December 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 12
      Author(s): Qing-chun LI, Li-juan LI, Guo-wei CHANG, Qi-jie ZHAI
      Carbide precipitation and martensite transformation in Cr5 steel have been observed in situ by high-temperature confocal laser-scanning microscopy. In this way, the influences of pulsed current and pulsed magnetic field complex pretreatment on carbide precipitation and martensite transformation during continuous cooling have been studied. The results show that the electropulsing complex pretreatment promotes the precipitation of M7C3-type carbides at high temperature, increases the start and finish temperatures of martensite transformation, and extends the phase transformation time. Martensite prefers to nucleate in the austenite with less precipitation of carbides due to the chemically homogeneous distribution of solute atoms.


      PubDate: 2016-01-20T10:38:17Z
       
  • Effect of Contact Pressure during Quenching on Microstructures and
           Mechanical Properties of Hot-stamping Parts
    • Abstract: Publication date: December 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 12
      Author(s): Zheng-wei GU, Meng-meng LÜ, Guan-han LU, Xin LI, Hong XU
      An experimental apparatus with cooling system and pressure-adjustment assembly for simulating quenching was constructed to investigate the effect of contact pressure on the microstructures and mechanical properties of hot-stamping parts. Qualitative and quantitative analyses of the microstructures of the as-quenched parts were conducted; moreover, hardness and tensile tests were performed to measure their mechanical properties. The results indicated that contact pressure during quenching strongly affected the structures and performances of hot-stamping components. An excessive low contact pressure led to insufficient martensitic transformation. The critical contact pressure for complete martensitic transformation for 4.0 mm 22MnB5 steel was 0. 4 MPa when the temperature of the coolant was 20 °C. However, in consideration of the efficiency of practical production, a contact pressure higher than 1.25 MPa is recommended.


      PubDate: 2016-01-20T10:38:17Z
       
  • High Ductility and Toughness of a Micro-duplex Medium-Mn Steel in Large
           Temperature Range from −196 C to 200 C
    • Abstract: Publication date: December 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 12
      Author(s): Si-lian CHEN, Jun HU, Xiao-dan ZHANG, Han DONG, Wen-quan CAO
      A medium-Mn steel (0. 2C5Mn) was processed by intercritical annealing at different temperatures (625 °C and 650 °C). An ultrafine-grained micro-duplex structure consisting of alternating austenite and ferrite laths was developed by austenite reverse transformation (ART) during intercritical annealing after forging and hot rolling. Ultrahigh ductility with a total elongation higher than 30% was achieved in the temperature range from −196 °C to 200 °C, and high impact toughness no less than 200 J at −40 °C was obtained. Based on the analysis of microstructure and mechanical properties, it was found that the enhanced ductility was determined by the phase transformation effect of austenite (TRIP effect), while the delayed ductile to brittle transition was controlled by austenite stability.


      PubDate: 2016-01-20T10:38:17Z
       
  • Effect of TiO2 on Crystallization, Microstructure and Mechanical
           Properties of Glass-ceramics
    • Abstract: Publication date: December 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 12
      Author(s): Jian YANG, Shen-gen ZHANG, Bo LIU, De-an PAN, Chun-li WU, Alex A. VOLINSKY
      The effect of TiO2 addition to the stainless steel slag glass-ceramics was studied. Different mass percentages of TiO2 were added to four samples of the parent glass made from stainless steel slag and cullet. The temperatures of nucleation and crystallization were determined by differential scanning calorimetry (DSC). According to X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis, adding TiO2 refined grains and restricted the formation of the akermanite phase by capturing Ca2+ to form the perovskite phase. Diopside was the main crystal phase of the glass-ceramics. The bending strength and Vickers hardness increased with the addition of TiO2. The optimal amount of TiCO2 was 7 mass%, and the highest bending strength and Vickers hardness were 144. 6 MPa and 6.26 GPa, respectively.


      PubDate: 2016-01-20T10:38:17Z
       
  • Silicon Strengthened CrAIVN Coatings
    • Abstract: Publication date: December 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 12
      Author(s): Qiang LI, Yue-xiu QIU, Bo LI, Dong-liang ZHAO, De-en SUN, De-hui LI
      CrAlVN coatings are of good intrinsic mechanical and tribological properties but lack of strength. Silicon can provide nitride coating high strength and excellent oxidation resistance. Logically, the combination of CrAlVN and Si should provide a good candidate for dry machining. The effect of silicon content on CrAlSiVN coating's mechanical, tribological properties and oxidation resistance was investigated. The coatings were deposited on cemented tungsten carbide and Si wafer (100) substrates in an in-line magnetron sputtering system. Grazing incidence X-ray diffractometer, scanning electron microscopy, atomic force microscopy, transmission electron microscopy, electron probe micro-analyzer, X-ray photoelectron spectroscopy and Auger electron spectroscopy were employed to characterize the microstructure and chemistry. Nanoindentation and ball-on-disc tribo-tester were used in characterization of the mechanical and tribological properties. Incorporating with silicon, the CrAlVN coating was strengthened (hardness: 21.2 GPa up to 38. 7 GPa); even after 2 h exposure to 700 °C in air, the hardness still maintains at 11.0 GPa.


      PubDate: 2016-01-20T10:38:17Z
       
  • Effects of Nitrogen Content and Austenitization Temperature on
           Precipitation in Niobium Micro-alloyed Steels
    • Abstract: Publication date: December 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 12
      Author(s): Lei CAO, Zhong-min YANG, Ying CHEN, Hui-min WANG, Xiao-li ZHAO
      The influences of nitrogen content and austenitization temperature on Nb(C, N) precipitation in niobium micro-alloyed steels were studied by different methods: optical microscopy, tensile tests, scanning electron microscopy, transmission electron microscopy, physicochemical phase analysis, and small-angle X-ray scattering. The results show that the strength of the steel with high nitrogen content is slightly higher than that of the steel with low nitrogen content. The increase in the nitrogen content does not result in the increase in the amount of Nb(C, N) precipitates, which mainly depends on the niobium content in the steel. The mass fraction of small-sized Nb(C, N) precipitates (1–10 nm) in the steel with high nitrogen content is less than that in the steel with low nitrogen content. After austenitized at 1150 °C, a number of large cuboidal and needle-shaped particles are detected in the steel with high nitrogen content, whereas they dissolve after austenitized at 1200 °C and the Nb(C, N) precipitates become finer in both steels. Furthermore, the results also show that part of the nitrogen in steel involves the formation of alloyed cementite.


      PubDate: 2016-01-20T10:38:17Z
       
  • Supplemental Information to “Method for Improving Transverse Wall
           Thickness Precision of Seamless Steel Tube Based on Tube Rotation”
           [J. Iron Steel Res. Int. 22 (2015) No. 10, 924-930]
    • Abstract: Publication date: December 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 12
      Author(s): Yong-zheng JIANG, Hua-ping TANG



      PubDate: 2016-01-20T10:38:17Z
       
  • Effect of H2O(g) Content in Circulating Flue Gas on Iron Ore Sintering
           with Flue Gas Recirculation
    • Abstract: Publication date: December 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 12
      Author(s): Xu-ling CHEN, Yun-song HUANG, Min GAN, Xiao-hui FAN, Zhi-yuan YU, Li-shun YUAN
      The influence of H2O(g) content in circulating flue gas on sintering was studied by simulating the flue gas circulating sintering. The results show that the burning speed of solid fuel and the heat transfer rate during sintering process are improved when the H2O (g) content increases from 0 to 6%, which accelerates the sintering speed. However, when the H2O (g) content exceeds 6%, the over-wet zone in sinter bed is thickened, which deteriorates the permeability of sintering bed. In addition, the magnetite content in sinter increases, while the acicular calcium ferrite content decreases. Accordingly, the sinter yield and tumble index decrease with excessive H2O (g) content. To guarantee the yield and quality of sinter, the favourable H2O (g) content in circulating flue gas should be controlled to be less than 6%.


      PubDate: 2016-01-20T10:38:17Z
       
  • DEM Simulation of Solid Flow Including Asymmetric Phenomena in COREX Shaft
           Furnace
    • Abstract: Publication date: December 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 12
      Author(s): Zhi-guo LUO, Heng ZHOU, Tao ZHANG, Yang YOU, Hai-feng LI, Zong-shu ZOU
      Based on the principles of the discrete element method (DEM), a scaled-down model was established to analyze burden descending behavior, including asymmetric phenomena, throughout an entire COREX shaft furnace (SF). The applicability of the DEM model was validated by determining its accordance with a previous experiment. The effects of discharge rate and abnormal conditions on solid flow were described in terms of solid flow pattern and microscopic analysis. Results confirmed that the solid flow of the COREX SF can be divided into four different flow regions; the largest normal force exists at the top of the man-made dead zone, and the weak force network exists in the funnel flow region. The basic solid flow profile was identified as a clear Flat?U?W type. Increasing the discharge rate decreased the quasi-stagnant zone size, but did not affect the macroscopic motion of particles or the shape of patterns above the bustle. For asymmetric conditions, in which particles were discharged at different rates, the solid flow patterns were asymmetric. Under an abnormal condition where no particles were discharged from the left outlet, a sizeable stagnant zone was formed opposite to the working outlet, and “motionless” particles located in the left stagnant zone showed potential to increase the period of static contacts and sticking effect.


      PubDate: 2016-01-20T10:38:17Z
       
  • Estimation of Energy Consumption in COREX Process Using a Modified Rist
           Operating Diagram
    • Abstract: Publication date: December 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 12
      Author(s): Wen-long ZHAN, Keng WU, Zhi-jun HE, Qi-hang LIU, Xiao-juan WU
      Fuel consumption in the COREX-3000 process run in Baosteel is currently higher than the design index. Therefore, mass and heat balance equations for the COREX process were established using the basic principles included in the Rist operating diagram for blast furnace (BF) as a reference. Thermodynamic calculations were then used to modify the Rist operating diagram so that it was suitable for the COREX process. The modified Rist operating diagram was then applied for the evaluation of metallization rate (MR) and fuel structure to reduce the energy consumption in the COREX process. The modified Rist operating diagram for the shaft furnace (SF) provided a nearly ideal value for the restriction point W when the metallization rate was increased, while the point P on the operating line for the melter gasifier (MG) moved upward due to reduction in the heat required in hearth. The feasibility of reducing the energy consumption during the COREX process by changing the fuel structure was also demonstrated.


      PubDate: 2016-01-20T10:38:17Z
       
  • Population Evolution of Oxide Inclusions in Ti-stabilized Ultra-low Carbon
           Steels after Deoxidation
    • Abstract: Publication date: December 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 12
      Author(s): Wen YANG, Ying ZHANG, Li-feng ZHANG, Hao-jian DUAN, Li WANG
      Population density function (PDF), which can eliminate the arbitrariness caused by the choice of the number and the size of bins compared to the well-used histograms, was introduced to analyze the amount of inclusions. The population evolution of oxide inclusions in forms of PDF in Ti-stabilized ultra-low carbon steels after deoxidation during industrial RH refining and continuous casting processes was analyzed using an automated SEM-EDS system. It was found that after deoxidation till the early stage of casting, the alumina inclusions exhibited a lognormal PDF distribution, and three factors including the existence of a large amount of alumina clusters, the generation of alumina from the reduction of Al-Ti-O inclusions and the reoxidation of molten steel were estimated as the reasons. The shape parameter σ was high after deoxidation and then decreased after Ti treatment, indicating that in a short period after deoxidation, the size of alumina inclusions was widely distributed. After Ti treatment, the distribution of inclusion size was more concentrated. The scale parameter m decreased with time during the whole refining process, indicating that the proportion of large inclusions decreased during refining. Contrarily, the Al-Ti-O inclusions presented a fractal PDF distribution except at the end of casting with fractal dimension D of 4.3, and the constant of proportionality C decreased with time during RH refining and increased during casting process. The reoxidation of steel by slag entrapped from ladle was considered as the reason for the lognormal PDF behavior of Al-Ti-O inclusions at the end of casting.


      PubDate: 2016-01-20T10:38:17Z
       
  • Analysis on Initial Defects Based on Mechanical State of Meniscus Shell
    • Abstract: Publication date: December 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 12
      Author(s): Xiang-ning MENG, Ren-gan LIN, Jie YANG, Xiao-jing ZUO, Miao-yong ZHU
      The meniscus shell plays an important role in slab quality and process operation for continuously cast steel. One decisive reason is initial solidifying shell and growing dendrite under the mechanical stress caused by mold oscillation and liquid steel flow to generate disturbance of casting. The mechanical state of meniscus shell was analyzed using mathematical models in combination with thermo-physical properties and flow rate of steel to shed light on the formation of initial defects. The results show that the mold oscillation is a critical factor on the initial crack formation because the periodic stress makes the shell bending. The formed crack may also expand and propagate due to the following secondary cooling and straightening behavior. The primary dendrite has high possibility to be broken by fluid flow in the solidification front to lead to the non-uniform thickness of solidifying shell. The inter-dendrite bridging is also likely to be formed to produce other internal defects, such as air hole and solute enrichment in the residual molten steel located in the bridging area.


      PubDate: 2016-01-20T10:38:17Z
       
  • Experimental Investigation on Viscosity of CaO-MgO(-Al2O3)-SiO2 Slags and
           Solid-liquid Mixtures
    • Abstract: Publication date: December 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 12
      Author(s): Ji-fang XU, Li-juan SU, Dong CHEN, Jie-yu ZHANG, Yao CHEN
      The viscosities for the selected CaO-MgO-SiO2 and CaO-MgO-Al2O3-SiO2 slags were measured by rotating cylinder method in a wide temperature range from 1608 K to 1823 K. The effects of temperature, slag basicity and Al2O3 content were studied. The results indicated that the viscosity decreased with increasing the slag basicity at the same temperature. And the viscosities of the slag initially increased linearly with increasing Al2O3 content in the slags and then decreased as the Al2O3 content in the slags continued to increase. Al2O3 addition has a more significant effect on the viscosity than slag basicity in the selected slags. Based on the experimental data and the fraction of solid phases calculated by the thermodynamic software, the effect of solid phases on slag viscosity was evaluated. The results indicated that the relationship between the relative viscosity and the volume fraction of solid phases estimated from the slag composition can be reasonable by allowing the inverse maximum fraction of solid particles to vary.


      PubDate: 2016-01-20T10:38:17Z
       
  • Critical Shear Offset of Fracture in a Zr-based Metallic Glass
    • Abstract: Publication date: January 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 1
      Author(s): Zhi-yuan LIU, Yong YANG, Chain-tsuan LIU
      The nanoscale shear band operation process of Zr55 Pd10 Cu20 Ni5 Al10 metallic glass (MG) was reined in by constant force during well-designed loading-holding-unloading cyclic microcompression test. Through the test, it is revealed that the whole shear banding process involves three stages: shear band initiation, shear sliding and shear band arrest. Based on the energy balance principle, the size-affected speed of shear sliding is interpreted. The energy originated from the shear sliding leads to heat-up of the shear plane; therefore, the temperature in shear band increases with the size of shear offset caused by the energy accumulation during shear sliding. Taking the glass transition temperature as the critical temperature of fracture for the Zr-based MG, the critical shear offset is predicted to be approximately 190 μm, fully in line with the experimental observation. This directly proved that the fracture of the MG is caused by the temperature rise during shear sliding.


      PubDate: 2016-01-16T10:25:25Z
       
  • Interactions of Shear Bands in a Ductile Metallic Glass
    • Abstract: Publication date: January 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 1
      Author(s): Li-shan HUO, Jun-qiang WANG, Jun-tao HUO, Yuan-yun ZHAO, He MEN, Chun-tao CHANG, Xin-min WANG, Run-wei LI
      Shear bands play a key role in the plastic deformation of metallic glasses (MGs). Even though there are extensive studies on the initiation and propagation of shear bands, the interactions among them have not been systematically studied yet. The interactions between the primary shear bands (PSBs) and secondary shear bands (SSBs) in a ductile Zr-based MG were studied. The residual stress near PSBs can deflect the propagation direction and reduce the propagation velocity of SSBs, which contributes to the plasticity and toughness of the MG. It was demonstrated that the probability and strength of the interactions between PSBs and SSBs would become stronger for MGs with larger Young's modulus and smaller shear modulus, i.e., larger Poisson's ratio. These results are valuable in understanding the plastic deformation of MGs and may be helpful in designing new MGs with desirable mechanical properties.


      PubDate: 2016-01-16T10:25:25Z
       
  • Effect of Oxygen on Microstructure Evolution and Glass Formation of
           Zr-based Metallic Glasses
    • Abstract: Publication date: January 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 1
      Author(s): Jia-lin CHENG, Guang CHEN, Qiang-qiang ZENG, Lu YUN, Feng XU
      The effect of oxygen on the microstructure evolution and glass formation of Zr-based bulk metallic glasses (BMGs) was studied in detail. It was found that oxygen did not form oxides or dissolve in glass matrix, but induced the precipitation of α-Zr which has the high affinity and solubility of oxygen in the Zr-based bulk metallic glass (Zr-BMG). With the precipitation of α-Zr, the remaining melts contain much lower oxygen content and have strong glass formation, resulting in the formation of α-Zr/BMG composite. The findings provide an important insight into the mechanism of the oxygen on glass formation, and give us a useful guideline to avoid the oxygen detrimental for designing new BMGs.


      PubDate: 2016-01-16T10:25:25Z
       
  • Serration Behavior in Zr-Cu-Al Glass-forming Systems
    • Abstract: Publication date: January 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 1
      Author(s): Zhong WANG, Jiao-jiao LI, Li-wei REN, Yong ZHANG, Jun-wei QIAO, Bao-cheng WANG
      The metallic glass matrix composites (MGMCs) and bulk metallic glasses (BMGs) were studied by statistical analysis during plastic deformation at the strain rates of 2×10−2, 2×10−3, and 2×10−4 s−1, respectively. No serration events occur in both MGMCs and BMGs during compression tests at the strain rate of 2×10−2 s−1 When deformed at the strain rate of 2 × 10−3 s−1, the BMG displays a larger plasticity, which is due to the larger serration events followed by a series of small serrations caused by the continuous movement of free volume. The amplitudes and elastic-energy densities increase with increasing the strain rates owing to many serrations in MGMCs. It is deduced that the Young's modulus decreases from the normalized stress drop and fluctuations are observed on stress-strain curves, which is attributed to a lower coefficient according to the stick-slip model.


      PubDate: 2016-01-16T10:25:25Z
       
  • Crystallization of a Ti-based Bulk Metallic Glass Induced by
           Electropulsing Treatment
    • Abstract: Publication date: January 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 1
      Author(s): Yong-jiang HUANG, Xiang CHENG, Hong-bo FAN, Shi-song GUAN, Zhi-liang NING, Jian-fei SUN
      The effect of electropulsing treatment (EPT) on the microstructure of a Ti-based bulk metallic glass (BMC) has been studied. The maximum current density applied during EPT can exert a crucial role on tuning the microstructure of the BMC. When the maximum current density is no more than 2720 A/mm2, the samples retains amorphous nature, whereas, beyond that, crystalline phases precipitate from the glassy matrix. During EPT, the maximum temperature within the samples EPTed at the maximum current densities larger than 2720 A/mm2 is higher than the crystallization temperature of the BMG, leading to the crystallization event.


      PubDate: 2016-01-16T10:25:25Z
       
  • Twinning Behavior of a Basal Textured Commercially Pure Titanium Alloy TA2
           at Ambient and Cryogenic Temperatures
    • Abstract: Publication date: January 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 1
      Author(s): Jin-ru LUO, Xiao SONG, Lin-zhong ZHUANG, Ji-shan ZHANG
      Twinning greatly affects the microstructure and mechanical performance of titanium alloys. The twinning behavior of a basal textured commercially pure titanium TA2 plates rolled to 4% reduction at the ambient and cryogenic temperatures has been investigated. Microstructures of the rolled samples were investigated by optical microscope (OM) and the twinning analysis was carried out based on orientation data collected by electron back-scatter diffraction (EBSD). {11 2} contraction twins, {11 4} contraction twins and {10 2} extension twins have been observed. Twinning mode activity varied with rolling temperature. Twinning is considered as the dominant deformation mechanism during rolling at both temperatures for the strain condition. Larger proportion of grains activates twinning during cryorolling, and greater number and more diverse types of twins are observed; manifestly related to the suppression of dislocation slips at the cryogenic temperature. {11 2} contraction twins are the dominate twin type within samples rolled at both temperatures. Several {11 4} contraction twins are observed in the cryorolled sample while there are only a few in the sample rolled at room temperature. A few tiny {10 2} twins have been identified in both samples. {11 4} contraction twins are preferentially activated at cryogenic deformation temperature and the {10 2} extension twins may result in local strain accommodation.


      PubDate: 2016-01-16T10:25:25Z
       
  • Constitutive Models for Compressive Deformation of AZ80 Magnesium Alloy
           under Multiple Loading Directions and Strain Rates
    • Abstract: Publication date: January 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 1
      Author(s): Xu-qing CHANG, Li-ying ZHANG, Yong-biao YANG, Jing-li REN
      Two constitutive models, the modified Johnson-Cook model and the logarithm linear relation model based on empirical approach and data analysis, were presented to illustrate compressive deformation of magnesium alloys AZ80 under multiple loading directions and strain rates. The results of stress-strain curve analysis and sensitivity index analysis suggested that the stress held large fluctuations in loading direction of 90°. Model testing signified that the logarithm linear relation model was more proper than the modified Johnson-Cook model in view of relative mean square error and correlation coefficients. Moreover, numerical simulation building on established models also indicated that the logarithm linear model is more precise than the modified Johnson-Cook model.


      PubDate: 2016-01-16T10:25:25Z
       
  • Tribological Properties of a Dendrite-reinforced Ti-based Metallic Glass
           Matrix Composite under Different Conditions
    • Abstract: Publication date: January 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 1
      Author(s): Teng ZHANG, Xiao-min LIN, Hui-jun YANG, Yong LIU, Yong-sheng WANG, Jun-wei QIAO
      The tribological properties of the in-situ dendrite-reinforced metallic glass matrix composite (Ti42 Zr22 V14 -Cu5 Be17) prepared by copper mould casting were analyzed at different normal loads under the dry condition and rainwater. The results showed that the average value of the frictional coefficients and micro-hardness ascended with increasing the normal load, while the wear rate showed a trend of decline under the dry condition. The electrochemical test results showed that the surface of samples was pitting corroded in the rainwater. The matrices were corroded first. Then the dendrites were exposed, leading to the damage of the surface. Both the frictional coefficients and wear rate of the composite in the rainwater were larger than those under the dry condition, primarily owing to the corrosion of chloride ions on the worn surface. The wear mechanisms of composites were mainly adhesive wear, accompanied by the abrasive wear under the dry condition and corrosive wear in the rainwater. The composites have higher wear resistance both under the dry condition and rainwater due to the lower wear rate.


      PubDate: 2016-01-16T10:25:25Z
       
  • Amorphization of Ni61Nb39 Alloy by Laser Surface Treatment
    • Abstract: Publication date: January 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 1
      Author(s): Zhong-xiang LU, Ran LI, Yan LI, Tao ZHANG
      The surface of Ni61 Nb39 crystalline ingot was treated by laser surface melting with different processing parameters. A fully amorphous layer with a thickness of approximately 10 μm could be produced on the top surface under optimal parameters. An amorphous-crystalline composite layer with the depth from 10 to 50 μm, consisting of amorphous matrix and intermetallic phases of Ni3Nb and Ni6Nb7, could be formed. The micro-hardness (about 831 HV) of the treated surface was remarkably improved by nearly 100% compared with the value of the crystalline substrate caused by the formation of the fully amorphous structure. A finite volume simulation was adopted to evaluate the temperature distribution in the laser-affected zone of Ni61 Nb39 alloys and to reveal the mechanism of glass formation in the laser-affected zone.


      PubDate: 2016-01-16T10:25:25Z
       
  • Influence of Zn Addition on Microstructures and Martensitic Transformation
           in CuZr-based Alloys
    • Abstract: Publication date: January 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 1
      Author(s): Kai-kai SONG, Dian-yu WU, Feng WAN, Xiao-jun BAI, Chong-de CAO
      Compositional dependences on microstructures and martensitic transformation behaviors in (Cu0.5 Zr0.5)100–x Zn x (x = 1.5, 2.5, 4, 5, 7.0, 10.0, and 14.0 at. %) alloys were investigated. It was found that CuZr martensites were present in the present alloys. With increasing Zn content, the volume fractions of CuZr martensitic crystals and B2 CuZr phase gradually decrease and increase, respectively. With the addition of high Zn contents (i.e., 7.0, 10.0, and 14.0 at. %), the matrix proves to be eutectic. Thermal analysis results show that the initial martensitic transformation temperature (Ms) decreases from (412±5) K to (329±5) K as the Zn content increases from 1.5 at. % to 14.0 at, %. The values of Ms of Cu-Zr-Zn shape memory alloys are inversely proportional to the number and concentrations of valence electrons (i.e., e v/a and c v), respectively, implying that the martensitic transformation in CuZr-Zn alloys could be of electronic nature.


      PubDate: 2016-01-16T10:25:25Z
       
  • Rate Dependence of Serrated Flow and Its Effect on Shear Stability of Bulk
           Metallic Glasses
    • Abstract: Publication date: January 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 1
      Author(s): Bao-an SUN, Chain-tsuan LIU, Yong YANG
      The rate dependence of serrated flow and its effects on the stability of shear banding were systematically investigated in a prototypic bulk metallic glass. It was found that with the increase of external strain rate, the serrated flow is gradually suppressed and could completely disappear at a critical strain rate. The serration size, characterized by the mean stress drop amplitude, decreases inversely with the strain rate, while the waiting time for serration decreases with the strain rate in a power-law manner. The rate dependence of the serrated flow has important effects on the dynamics and stability of shear banding process, and leads to an optimal plasticity achieved around the critical strain rate for the disappearance of serrated flow. These results are discussed and interpreted in terms of the microscopic deformation theory and the stick-slip dynamics of shear banding for bulk metallic glasses.


      PubDate: 2016-01-16T10:25:25Z
       
  • Insight on Viscoelasticiy of Ti16.7 Zr16.7 Hf16.7 Cu16.7 Ni16.7 Be16.7
           High Entropy Bulk Metallic Glass
    • Abstract: Publication date: January 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 1
      Author(s): Ji-chao QIAO, Jean-marc PELLETIER, Ning LI, Yao YAO
      High entropy bulk metallic glasses show promising mechanical and physical properties. Dynamic mechanical properties of Ti16.7 Zr16.7 Hf16.7 Cu16.7 NU16.7 Be16.7 high entropy bulk metallic glass were investigated by mechanical spectroscopy (or called dynamic mechanical analysis). The main (α) relaxation was observed in the framework of the loss modulus G“, which is related to the dynamic glass transition behaviour for the glassy materials. From physical model point of view, dynamic mechanical properties of the Ti16.7 Zr16.7 Hf16.7 Cu16.7 Ni16.7 Be16.7 high entropy bulk metallic glass show good agreement compared with the quasi-point defects theory.


      PubDate: 2016-01-16T10:25:25Z
       
  • Microstructure Evolution and Mechanical Properties of Spray-deposited
           Al-21. 47Si-4. 73Fe-2. 5Cu-0. 9Mg Alloy
    • Abstract: Publication date: January 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 1
      Author(s): Yan-dong JIA, Fu-yang CAO, Pan MA, Jing-shun LIU, Jian-fei SUN, Gang WANG
      Al-Si-Fe-Cu-Mg alloy was prepared by spray deposition and was further processed by hot extrusion as well as T6 heat-treatment. The results indicate that the microstructure of the deposited alloy is composed of primary Si particles with average size of less than 5 μm, α-Al, Al2 CuMg, β-Al5 EeSi and δ-Al4FeSi2 (rectangular shape), and no eutectic silicon is found due to the special solidification behavior. The age hardening curves reveal two peaks. The uniform ultimate tensile strength (UTS) and the elongation of the peak-aged Al-Si-Fe-Cu-Mg alloy are 468. 3 MPa, 0.61% at 298 K and 267.4 MPa, 6.42% at 573 K, respectively. The fracture surfaces display brittle fracture morphology at 298 K, whereas it varies to mixture of brittle and ductile failure with increasing the temperature.


      PubDate: 2016-01-16T10:25:25Z
       
  • Self-organized Criticality Behavior in Bulk Metallic Glasses
    • Abstract: Publication date: January 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 1
      Author(s): Jun-wei QIAO, Zhong WANG
      Serrated flows are known as repeated yielding of bulk metallic glasses (BMGs) during plastic deformation under different loading conditions, which are associated with the operation of shear banding. According to the statistics of some parameters, the shear avalanches can display a self-organized critical state, suggesting a large ductility of BMGs. The emergence of the self-organized criticality (SOC) behavior in different BMGs is due to the temperature, strain rate, and chemical compositions. The SOC behavior is accompanied with the following phenomena: the interactions occur in the shear bands; the incubation time is longer than the relaxation time; the time interval is lacking of typical time scale; and the spatial or temporal parameters should display a power-law distribution.


      PubDate: 2016-01-16T10:25:25Z
       
  • Serration and Noise Behavior in Advanced Materials
    • Abstract: Publication date: January 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 1
      Author(s): Yong ZHANG, Wei-hua WANG, Peter K. LIAW, Gang WANG, Jun-wei QIAO



      PubDate: 2016-01-16T10:25:25Z
       
  • A Brief Review of High Entropy Alloys and Serration Behavior and Flow
           Units
    • Abstract: Publication date: January 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 1
      Author(s): Yong ZHANG, Jun-wei QIAO, Peter K. LIAW
      Multicomponent alloys with high entropy of mixing, e.g., high entropy alloys (HEAs) and/or multiprincipal-element alloys (MEAs), are attracting increasing attentions, because the materials with novel properties are being developed, based on the design strategy of the equiatomic ratio, multicomponent, and high entropy of mixing in their liquid or random solution state. Recently, HEAs with the ultrahigh strength and fracture toughness, excellent magnetic properties, high fatigue, wear and corrosion resistance, great phase stability/high resistance to heat-softening behavior, sluggish diffusion effects, and potential superconductivity, etc., were developed. The HEAs can even have very high irradiation resistance and may have some self-healing effects, and can potentially be used as the first wall and nuclear fuel cladding materials. Serration behaviors and flow units are powerful methods to understand the plastic deformation or fracture of materials. The methods have been successfully used to study the plasticity of amorphous alloys (also bulk metallic glasses, BMGs). The flow units are proposed as: free volumes, shear transition zones (STZs), tension-transition zones (TTZs), liquid-like regions, soft regions or soft spots, etc. The flow units in the crystalline alloys are usually dislocations, which may interact with the solute atoms, interstitial types, or substitution types. Moreover, the flow units often change with the testing temperatures and loading strain rates, e.g., at the low temperature and high strain rate, plastic deformation will be carried out by the flow unit of twinning, and at high temperatures, the grain boundary will be the weak area, and play as the flow unit. The serration shapes are related to the types of flow units, and the serration behavior can be analyzed using the power law and modified power law.


      PubDate: 2016-01-16T10:25:25Z
       
  • Process and Quality Control during High Speed Casting of Low Carbon
           Conventional Slab
    • Abstract: Publication date: November 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Supplement 1
      Author(s): Lin-ping LI, Xin-hua WANG, Xiao-xuan DENG, Chen-xi JI
      Based on the achievement of 2.5 m/min casting speed on Shougang Jingtang (SGJT) No. 3 slab caster, effect of casting speed on the parameters closely related to the casting conditions was discussed elaborately by plant trial, mathematical simulation and experimental study respectively. The results showed that mold level fluctuation, surface velocity, average heat flux, bulging of broad face, temperature of copper plate, solidification crater end and frictional force entirely increased while the powder consumption rate, subsurface inclusions and depth of hook structure decreased with the increase of casting speed. As a consequence, flow control mold (FC mold) was more significant to control the mold level than submerged entry nozzle (SEN) and powder B was more appropriate for high speed casting than powder A. And further, it is highly recommended that high speed casting should be considered as a potential application to improve the surface quality of cold coils.


      PubDate: 2016-01-12T10:03:39Z
       
  • Characteristics and Evolution of Inclusion Induced Surface Defects of Cold
           Rolled IF Sheet
    • Abstract: Publication date: November 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Supplement 1
      Author(s): Hui-xiang YU, Chen-xi JI, Bin CHEN, Chang WANG, Ying-hua ZHANG
      Cold rolled IF sheet has a high requirement for surface quality. Nowadays, more than half of surface defects in cold rolled sheet are caused by non-metallic inclusions generated in steelmaking and casting process. Three types of surface defects as sliver, peeling and hole were found in industrial samples. To investigate the evolution process of inclusion induced surface defects, hot rolling and cold rolling of industrial slab samples were carried out in pilot mill, then surface defects after cold rolling were analyzed with scanning electron microscope equipped with energy dispersive spectrometer (SEM-EDS). The results show that, the inclusions which create surface defects are mainly from deoxidation products and entrapped mold powder. Surface defects like pockmark, peeling, dent and scratch in cold rolled IF sheet are determined by position, size and property of the inclusions. Subcutaneous big size inclusions can lead to peeling and dent, while surface inclusion particles would lead to pockmark and scratch or sliver. To improve surface quality of cold rolled sheet, some measures should be adopted to further decrease and remove macro inclusions, and avoid hard inclusions to be bare to the slab surface.


      PubDate: 2016-01-12T10:03:39Z
       
  • Briquette Smelting in Electric Arc Furnace to Recycle Wastes from
           Stainless Steel Production
    • Abstract: Publication date: November 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Supplement 1
      Author(s): Qi-xing YANG, An-jun XU, Peng XUE, Dong-feng HE, Jian-li LI, Bo BJÖRKMAN
      Wastes from stainless steel production were briquetted together with carbon for smelt-reduction in the electric arc furnace, EAF, to achieve an internal recycling. A laboratory induction furnace was used to simulate the EAF. With a close simulation of the smelting, disintegration of the briquettes heated under load and recovery of metals from briquettes melted together with stainless steel and slag former were investigated. The influences of test conditions on carbon reduction of oxides in the briquettes were also examined. The briquettes endured heating at 1 186 °C under load of 3.5 kg and could be charged to the melt in small quantity without causing serious splashing. For a high metal recovery, it was necessary to charge the briquettes together with slag former. Small local zones of smelt-reduction with high carbon concentration could thus be formed during the charger heating. Silicon content in the metal near to the briquettes should be minimised to achieve a high degree of carbon reduction. Based on results obtained from this study, suggestions were made on smooth operations of smelt-reduction of the briquettes by using EAF or induction furnace with large scales.


      PubDate: 2016-01-12T10:03:39Z
       
  • Formation of Hearth Sediment during Vanadium Titano-magnetite Smelting in
           Blast Furnace No.7 of Chengde Iron and Steel Company
    • Abstract: Publication date: November 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 11
      Author(s): Xiao-jie LIU, Qing LÜ, Shu-jun CHEN, Zhen-feng ZHANG, Shu-hui ZHANG, Yan-qin SUN
      The large quantity of sediment produced in the hearth during vanadium titano-magnetite smelting in a blast furnace (BF) affects the stability of the blast furnace operation. Testing and analysis of the sediment in the hearth of Chengde Iron and Steel Company's BF No.7 revealed that it was mainly concentrated in the location below the tuyere and above the iron notch. Notably, some of the bonding material (sediment) consisted of greater than 50% pig iron, and the pig iron distributed in the slag was granular. It is proposed that a large quantity of TiC and Ti(C,N) are deposited on the surface of the pig iron. These high melting point materials mix with iron drops, preventing the slag from flowing freely, thus leading to the formation of bonding materials. In addition, the viscosity and melting temperature of the slag in the tuyere areas fluctuate greatly, and thus the properties of the slag are unstable. Moreover, the slag contains large quantities of carbon, which results in the reduction of TiO2. The resultant precipitation of Ti is followed by the formation of TiC in the slag, which also leads to an increase in the viscosity of the slag and difficulty in achieving separation of the slag-iron. In fact, all of these factors interact with each other, and as a result, sediment is formed when the operating conditions in the hearth fluctuate.


      PubDate: 2015-12-19T12:19:14Z
       
  • Manufacturing Technology and Application Trends of Titanium Clad Steel
           Plates
    • Abstract: Publication date: November 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 11
      Author(s): Hang SU, Xiao-bing LUO, Feng CHAI, Jun-chang SHEN, Xin-jun SUN, Feng LU
      Some of the major manufacturing processes and corresponding mechanical properties of titanium clad steel plates were analyzed, and the consequences of research, manufacturing, and application of titanium clad steel plates in both markets of China and overseas were also summarized. As an economical and environmentally friendly technology, the roll bonding process is expected to become the next-generation mainstream process for the manufacturing of titanium clad steel plate. Some of the crucial and most important technical problems of this particular process, including vacuum sealing technology, surface treatment process technology, application of a transition layer, and rolling process, were discussed along with the advantageous mechanical properties and life-cycle economy of these plates processed by this technology. Finally, the market needs, application trends, and requirements of titanium clad steel plate were also considered from industries of petrochemical, shipbuilding, marine, and electric power.


      PubDate: 2015-12-19T12:19:14Z
       
  • Effect of Precipitation on Intergranular Corrosion Resistance of 430
           Ferritic Stainless Steel
    • Abstract: Publication date: November 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 11
      Author(s): Xun-zeng HUANG, Dan WANG, Yi-tao YANG
      With Nb-Ti-stabilized 430 ferritic stainless steel (NTS430FSS) and SUS 430 ferritic stainless steel (SUS430FSS) as experimental materials, the influence of precipitation on intergranular corrosion resistance was investigated. A series of aging treatment were carried out. The free-exposure corrosion test and double loop electrochemical potentiokinetic reactivation (DL-EPR) test with a scan rate of 1.67 mV/s at 26 °C were applied to evaluate the intergranular corrosion (IGC) resistance. Metallographic observation, scanning electron microscope (SEM), transmission electron microscope (TEM) with energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD) analysis were conducted. The results show that IGC occurred in SUS430FSS aged above 700 °C, while it occurred in NTS430FSS as the temperature was improved to 1 050 °C. The critical degree of sensitization I r/I a reaches 0.305 in SUS430FSS, which is higher than that of NTS430FSS, i.e. 0.010, aged at 950 °C for 2 h. The TEM, EDS and XRD results show that a large amount of Cr23C6 precipitates with size of 60 nm×22 nm are located at the SUS430FSS grain boundaries as chains. With the addition of Nb and Ti and reduction of C, the amount of precipitates reduces significantly in NTS430FSS. A majority of Cr23C6 were replaced by TiC and NbC. Only a small amount of spherical TiC (R=186 nm) and square TiN (312 nm×192 nm) with Nb and Cr adsorbed are left along grain boundaries. Due to the dual stabilization of Nb and Ti, the precipitation of Cr23C6 is restrained, the chromium depleted region is avoided and accordingly the resistance to the intergranular corrosion is improved.


      PubDate: 2015-12-19T12:19:14Z
       
  • Effects of Cr Content and Annealing Temperature on Microstructure and Wear
           Characteristics of Cast Ausferrite Nodular Iron
    • Abstract: Publication date: November 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 11
      Author(s): Jia-peng ZOU, Kazumichi SHIMIZU, Qi-zhou CAI
      The effects of Cr content and annealing temperature on abrasive wear characteristics of cast ausferrite nodular iron were investigated with Suga type abrasive wear tester. The surface morphology and Vickers hardness of the tested samples were analyzed by scanning electron microscopy (SEM), digital microscope and Vickers hardness tester. The results show that the cast ausferrite nodular iron could be obtained by alloying with Cr in the as-cast ductile cast iron and permanent mold casting, and the bainite content in the matrix increased with increasing Cr content. However, the decomposition of bainite took place during annealing at 500 °C to 800 °C; especially, at 800 °C, the bainite transformed into a mixture of fine lamellar pearlite and ferrite matrix structure. The wear loss of specimens was reduced with increasing Cr content in the cast ausferrite nodular iron. The wear loss of the sample cast ausferrite nodular iron with 0.4mass% Cr is the least. The wear loss began to increase while the Cr content is 0.6mass%. The wear loss of annealed ductile irons at different annealing temperatures was higher than that of as-cast samples. During the abrasive wear, the shear stress transformed austenite to martensite, and the hardness of specimens increased and the wear resistance of as-cast ductile cast iron was improved.


      PubDate: 2015-12-19T12:19:14Z
       
  • Effect of Chromium on Microstructure and Mechanical Properties of Cold
           Rolled Hot-dip Galvanizing DP450 Steel
    • Abstract: Publication date: November 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 11
      Author(s): Yun HAN, Shuang KUANG, Hua-sai LIU, Ying-hua JIANG, Guang-hui LIU
      Two cold rolled hot-dip galvanizing dual phase (DP) 450 steels with different amounts of chromium were designed and the effects of the chromium concentration and galvanizing processes on the microstructure and mechanical properties were also investigated. The results show that the experimental steels exhibit typical dual phase microstructure character. However, the ferrite phase of steel with higher chromium is more regular and its boundaries are clearer. Meanwhile, martensite austenite (MA) island in steel No. 2 is diffused and no longer distributes along the grain boundary as net or chain shape. More MA islands enriched with Cr element can be found in the ferrite grains, and the increment of Cr element improves the stablity of the austenite so that the austenite has been reserved in MA islands. In addition, the experimental steel with higher chromium exhibits better elongation, lower yield ratio and better formability. The mean hole expanding ratio of steels No. 1 and No. 2 is 161.70% and 192.70%, respectively.


      PubDate: 2015-12-19T12:19:14Z
       
  • Hot Deformation Behavior of GH738 for A-USC Turbine Blades
    • Abstract: Publication date: November 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 11
      Author(s): Li WANG, Gang YANG, Ting LEI, Shu-biao YIN, Lu WANG
      The hot deformation characteristics of GH738 superalloy over the temperature range of 1 000 °C to 1 200 °C and strain range of 0.01 s−1 to 10.0 s−1 under a strain of 1.0 s−1 were investigated through hot compression tests with a Gleeble-1500 simulation machine. The flow stress reached peak value before flow softening occurred. The average apparent activation energy (Q) of GH738 was calculated to be 430 kJ/mol, and the stress index (n) is approximately 4.08. The processing map was developed based on flow stress data and dynamic materials model (DMM). The map shows a dynamic recrystallization (DRX) domain in 1 050 °C to 1 150 °C and 0.01 s−1 to 1.0 s−1 strain rate range with a peak efficiency of 45%, which is considered to be the optimum region for hot working. Moreover, the materials undergo flow instability in the temperature range of 1 000 °C to 1 050 °C and strain range of 1.0 s−1 to 10.0 s−1, and adiabatic shear bands can be observed in this domain.


      PubDate: 2015-12-19T12:19:14Z
       
  • Precipitation Behavior of V-N Microalloyed Steels during Normalizing
    • Abstract: Publication date: November 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 11
      Author(s): Tao PAN, Xi-yang CHAI, Jin-guang WANG, Hang SU, Cai-fu YANG
      The precipitation behavior of V-N microalloyed steel during normalizing process was studied by physicochemical phase analysis and transmission electron microscopy (TEM). The effect of precipitation behavior on mechanical properties was investigated by theoretical calculations. The results showed that 32.9% of V(C,N) precipitates remained undissolved in the austenite during the soaking step of the normalizing process. These precipitates prevented the growth of the austenite grains. During the subsequent cooling process, the dissolved V(C,N) re-precipitated and played a role in precipitation strengthening. The undissolved V(C,N) induced intragranular ferrite nucleation and refined the ferrite grains. Consequently, compared with hot-rolled steel, the normalized steel exhibited increased grain-refining strengthening but diminished precipitation strengthening, leading to an improvement of the impact energy at the expense of about 40 MPa yield strength.


      PubDate: 2015-12-19T12:19:14Z
       
  • Relationship between Dislocation Density in P91 Steel and Its Nonlinear
           Ultrasonic Parameter
    • Abstract: Publication date: November 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 11
      Author(s): Ye-qing CAI, Jin-zhong SUN, Cheng-jie LIU, Shi-wei MA, Xi-cheng WEI
      P91 steel is an important bearing material used in nuclear power plants. The study of its mechanical degradation behavior is important for ensuring safe operation. The relationship between the dislocation density of P91 steel under different strains and the corresponding nonlinear ultrasonic parameter β was studied. The dislocation density of strained samples was estimated by X-ray diffraction. Nonlinear ultrasonic testing was conducted to evaluate β, showing that this value increased with increasing dislocation density induced by different tensile elongations. It was shown that the ultrasonic second-harmonic generation technique can effectively evaluate the degradation behavior of metallic materials, and the prediction of the residual life of bearing parts in service can be made based on β and the dislocation density.


      PubDate: 2015-12-19T12:19:14Z
       
  • Effect of Subcritical Annealing Temperature on Microstructure and
           Mechanical Properties of SCM435 Steel
    • Abstract: Publication date: November 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 11
      Author(s): Cheng JI, Lei WANG, Miao-yong ZHU
      The effect of subcritical annealing temperature on microstructure and mechanical properties of SCM435 steel was investigated through changing the heating and soaking temperature as 660 °C, 680 °C, 700 °C, 720 °C and 745 °C. The microstructure and mechanical properties of intercritically annealed specimens were analyzed. With increasing the subcritical annealing temperature from 660 °C to 720 °C, the spheroidization ratio gradually increased, and the mechanical properties, formability and Vickers hardness were improved. According to the comprehensive comparison of mechanical properties and formability, the subcritical process at soaking temperature of 680–720 °C could achieve similar annealing effect as that of intercritical process. Therefore, the subcritical annealing temperature could be set as 700 °C in practice, with the A c1 temperature fluctuation within ±20 °C, and the applicability and stability of subcritical annealing were guaranteed in industrial application. The plant results of the cold heading showed that the subcritical annealing could replace original intercritical annealing successfully with significantly saving time and energy.


      PubDate: 2015-12-19T12:19:14Z
       
  • Mn Diffusion at Early Stage of Intercritical Annealing of 5Mn Steel
    • Abstract: Publication date: November 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 11
      Author(s): Xi-nan LUO, Xiao-yan ZHONG, Hai-wen LUO, Hui-hua ZHOU, Cun-yu WANG, Jie SHI
      Mn distribution and austenite morphology at the early stage of intercritical annealing of 5Mn steel were investigated. It was experimentally demonstrated that a newly formed 20 nm-thick austenite was formed without the partitioning of Mn. The elemental analysis confirmed that the growth of austenite should be controlled by the diffusion of C prior to the diffusion of Mn at a low heating rate. The austenite growth started under negligible-partitioning local equilibrium mode and then switched to partitioning local equilibrium mode. Mn segregation at the γ/α interface suggested that the collector plate mechanism was the essential way of Mn partitioning at the early stage of austenite growth.


      PubDate: 2015-12-19T12:19:14Z
       
  • Corrosion Behavior of S450EW Low-alloy Weathering Steel in Cyclically
           Alternate Corrosion Environments
    • Abstract: Publication date: November 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 11
      Author(s): Jun-shan WANG, Pei-yang SHI, Cheng-jun LIU, Mao-fa JIANG
      Weathering steel is widely used in various fields due to its excellent mechanical properties and high corrosion resistance. The effect of chromium content on the S450EW weathering steel in cyclic immersion test was studied. The results indicated that the corrosion resistance of S450EW weathering steel is closely related to chromium content. The addition of chromium significantly inhibited the weathering steel corrosion. The corrosion rate of experimental steel after 96 h immersion was 1.101 g·m−2·h−1. The rust of S450EW weathering steel was mainly constituted of FeOOH and Fe3O4 phase, and the elevation of chromium content promoted the formation of α-FeOOH. The fine precipitates of the two phases contributed to the formation of dense dust layer of test steel. Furthermore, the increase of chromium is beneficial for the cure of original defects and cracks of the rust layer via the enrichment of chromium. The corrosion potential and the resistance of corrosion process were thus increased, protecting the experimental steel from further corrosion. A S450EW steel with corrosion resistance more than 1.5 times of Q450NQR1 steel was prepared.


      PubDate: 2015-12-19T12:19:14Z
       
  • Optimization of Cooling Process of Iron Ore Pellets Based on Mathematical
           Model and Data Mining
    • Abstract: Publication date: November 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 11
      Author(s): Gui-ming YANG, Xiao-hui FAN, Xu-ling CHEN, Xiao-xian HUANG, Xi LI
      Cooling process of iron ore pellets in a circular cooler has great impacts on the pellet quality and systematic energy exploitation. However, multi-variables and non-visualization of this gray system is unfavorable to efficient production. Thus, the cooling process of iron ore pellets was optimized using mathematical model and data mining techniques. A mathematical model was established and validated by steady-state production data, and the results show that the calculated values coincide very well with the measured values. Based on the proposed model, effects of important process parameters on gas-pellet temperature profiles within the circular cooler were analyzed to better understand the entire cooling process. Two data mining techniques—Association Rules Induction and Clustering were also applied on the steady-state production data to obtain expertise operating rules and optimized targets. Finally, an optimized control strategy for the circular cooler was proposed and an operation guidance system was developed. The system could realize the visualization of thermal process at steady state and provide operation guidance to optimize the circular cooler.


      PubDate: 2015-12-19T12:19:14Z
       
  • Plate Shape Control Theory and Experiment for 20-high Mill
    • Abstract: Publication date: November 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 11
      Author(s): Zheng-wen YUAN, Hong XIAO
      Roll flattening theory is an important part of plate shape control theories for 20-high mill. In order to improve the accuracy of roll flattening calculation for 20-high mill, a new and more accurate roll flattening model was proposed. In this model, the roll barrel was considered as a finite length semi-infinite body. Based on the boundary integral equation method, the numerical solution of the finite length semi-infinite body under the distributed force was obtained and an accurate roll flattening model was established. Coupled with roll bending model and strip plastic deformation, a new and more accurate plate control model for 20-high mill was established. Moreover, the effects of the first intermediate roll taper angle and taper length were analyzed. The tension distribution calculated by analytical model was consistent with the experimental results.


      PubDate: 2015-12-19T12:19:14Z
       
  • Behavior of Element Vaporization and Composition Control of Fe-Ga Alloy
           during Vacuum Smelting
    • Abstract: Publication date: November 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 11
      Author(s): Jian-wu YAN, Liang LUO, A-fang PENG, Chen-shu ZHANG, Qing-hua CAO
      Saturated vapor pressure, critical evaporation temperature and evaporation loss rate of Fe-Ga alloy were calculated under different conditions of Ga and Fe contents with activity coefficients. The relationship between the change of Ga content and melting time was determined. The results demonstrated that saturated vapor pressure of Ga was higher than that of Fe under the same conditions. The difference value of critical evaporation temperature of Ga with and without Ar was nearly 800 K. The critical evaporation temperature of Fe was higher than that of Ga under vacuum, indicating that Ga was more volatile than Fe. At 1 800 K, the evaporation rate of Ga was 84 times higher than that of Fe in the melt of Fe81Ga19 alloy. Under this condition, the change of Ga content and smelting time kept a linear relationship. The higher the temperature was, the faster the Ga content decreased, which was consistent with theoretical calculations.


      PubDate: 2015-12-19T12:19:14Z
       
  • Analysis on Shear Deformation for High Manganese Austenite Steel during
           Hot Asymmetrical Rolling Process Using Finite Element Method
    • Abstract: Publication date: November 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 11
      Author(s): Feng-li SUI, Xin WANG, Jun ZHAO, Biao MA, Chang-sheng LI
      Based on the rigid-plastic finite element method (FEM), the shear stress field of deformation region for high manganese austenite steel during hot asymmetrical rolling process was analyzed. The influences of rolling parameters, such as the velocity ratio of upper to lower rolls, the initial temperature of workpiece and the reduction rate, on the shear deformation of three nodes in the upper, center and lower layers were discussed. As the rolling parameters change, distinct shear deformation appears in the upper and lower layers, but the shear deformation in the center layer appears only when the velocity ratio is more than 1.00, and the absolute value of the shear stress in this layer is changed with rolling parameters. A mathematical model which reflected the change of the maximal absolute shear stress for the center layer was established, by which the maximal absolute shear stress for the center layer can be easily calculated and the appropriate rolling technology can be designed.


      PubDate: 2015-12-19T12:19:14Z
       
 
 
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