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  Subjects -> ENVIRONMENTAL STUDIES (Total: 775 journals)
    - ENVIRONMENTAL STUDIES (711 journals)
    - POLLUTION (21 journals)
    - TOXICOLOGY AND ENVIRONMENTAL SAFETY (35 journals)
    - WASTE MANAGEMENT (8 journals)

ENVIRONMENTAL STUDIES (711 journals)            First | 1 2 3 4 5 6 7 8     

International Aquatic Research     Open Access   (Followers: 3)
International Archives of Occupational and Environmental Health     Hybrid Journal   (Followers: 5)
International Environmental Agreements: Politics, Law and Economics     Hybrid Journal   (Followers: 10)
International Gambling Studies     Hybrid Journal   (Followers: 5)
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: 2)
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: 1)
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: 1)
International Journal of Corrosion     Open Access   (Followers: 10)
International Journal of Critical Infrastructures     Hybrid Journal   (Followers: 3)
International Journal of Disaster Risk Reduction     Hybrid Journal   (Followers: 6)
International Journal of Disaster Risk Science     Open Access   (Followers: 8)
International Journal of Ecological Economics and Statistics     Full-text available via subscription   (Followers: 1)
International Journal of Ecology     Open Access   (Followers: 8)
International Journal of Ecology & Development     Full-text available via subscription   (Followers: 1)
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: 7)
International Journal of Environment and Pollution     Hybrid Journal   (Followers: 6)
International Journal of Environment and Sustainable Development     Hybrid Journal   (Followers: 14)
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 Engineering     Open Access  
International Journal of Environmental Health Research     Hybrid Journal   (Followers: 3)
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: 14)
International Journal of Environmental Science and Technology     Hybrid Journal   (Followers: 5)
International Journal of Environmental Studies     Hybrid Journal   (Followers: 11)
International Journal of Exergy     Hybrid Journal   (Followers: 4)
International Journal of Forest, Soil and Erosion     Open Access   (Followers: 3)
International Journal of Global Environmental Issues     Hybrid Journal   (Followers: 4)
International Journal of Global Warming     Hybrid Journal   (Followers: 5)
International Journal of Greenhouse Gas Control     Partially Free   (Followers: 6)
International Journal of Health Planning and Management     Hybrid Journal   (Followers: 6)
International Journal of Hygiene and Environmental Health     Hybrid Journal   (Followers: 6)
International Journal of Logistics Research and Applications : A Leading Journal of Supply Chain Management     Hybrid Journal   (Followers: 9)
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: 1)
International Journal of Regulation and Governance     Hybrid Journal   (Followers: 2)
International Journal of Reliability and Safety     Hybrid Journal   (Followers: 6)
International Journal of Renewable Energy Development     Open Access   (Followers: 6)
International Journal of Social Sciences and Management     Open Access  
International Journal of Soil, Sediment and Water     Open Access   (Followers: 8)
International Journal of Stress Management     Full-text available via subscription   (Followers: 8)
International Journal of Sustainable Construction Engineering and Technology     Open Access   (Followers: 7)
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: 7)
International Journal of Testing     Hybrid Journal   (Followers: 1)
International Journal of the Commons     Open Access   (Followers: 3)
International Journal of Toxicology     Hybrid Journal   (Followers: 6)
International Journal of Water Resources and Environmental Engineering     Open Access   (Followers: 1)
International Review of Environmental and Resource Economics     Full-text available via subscription  
International Studies in the Philosophy of Science     Hybrid Journal   (Followers: 9)
Interventions : International Journal of Postcolonial Studies     Hybrid Journal   (Followers: 7)
IOP Conference Series: Earth and Environmental Science     Open Access   (Followers: 7)
Iranian Journal of Environmental Health Science & Engineering     Open Access   (Followers: 1)
Iranian Studies     Hybrid Journal   (Followers: 7)
Irish Educational Studies     Hybrid Journal   (Followers: 2)
Irish Journal of Earth Sciences     Full-text available via subscription  
Irish Political Studies     Hybrid Journal   (Followers: 8)
ISLE: Interdisciplinary Studies in Literature and Environment     Hybrid Journal   (Followers: 2)
Isotopes in Environmental and Health Studies     Hybrid Journal   (Followers: 2)
Israel Studies     Full-text available via subscription   (Followers: 5)
ISRN Ecology     Open Access  
ISRN Environmental Chemistry     Open Access  
Jahangirnagar University Environmental Bulletin     Open Access  
Journal of Bioremediation & Biodegradation     Open Access   (Followers: 2)
Journal of Earth Science & Climatic Change     Open Access   (Followers: 8)
Journal of Petroleum & Environmental Biotechnology     Open Access   (Followers: 2)
Journal of Advances in Environmental Health Research     Open Access  
Journal of Agricultural and Environmental Ethics     Hybrid Journal   (Followers: 8)
Journal of Agricultural Biotechnology and Sustainable Development     Open Access  
Journal of Agricultural Chemistry and Environment     Open Access  
Journal of Agriculture and Environment     Open Access  
Journal of Agriculture and Environment for International Development     Open Access   (Followers: 6)
Journal of Agrobiology     Open Access   (Followers: 2)
Journal of Applied Ecology     Hybrid Journal   (Followers: 210)
Journal of Applied Meteorology and Climatology     Full-text available via subscription   (Followers: 7)
Journal of Applied Psychoanalytic Studies     Hybrid Journal   (Followers: 1)
Journal of Applied Sciences and Environmental Management     Open Access   (Followers: 1)
Journal of Applied Sciences in Environmental Sanitation     Open Access   (Followers: 6)
Journal of Applied Toxicology     Hybrid Journal   (Followers: 9)
Journal of Applied Volcanology     Open Access   (Followers: 8)
Journal of Arid Environments     Hybrid Journal   (Followers: 8)
Journal of Asian Studies     Full-text available via subscription   (Followers: 23)
Journal of Biochemical and Molecular Toxicology     Hybrid Journal   (Followers: 5)
Journal of Black Studies     Hybrid Journal   (Followers: 2)
Journal of Chemical Ecology     Hybrid Journal   (Followers: 2)
Journal of Chemical Health and Safety     Hybrid Journal   (Followers: 3)
Journal of Climate     Full-text available via subscription   (Followers: 24)

  First | 1 2 3 4 5 6 7 8     

Journal Cover Journal of Iron and Steel Research, International
   [9 followers]  Follow    
   Full-text available via subscription Subscription journal
     ISSN (Print) 1006-706X
     Published by Elsevier Homepage  [2571 journals]   [SJR: 0.586]   [H-I: 13]
  • Slag/metal Separation Process of Gas-reduced Oolitic High-phosphorus Iron
           Ore Fines
    • Abstract: Publication date: November 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 11
      Author(s): Hui-qing TANG , Long MA , Jun-wei WANG , Zhan-cheng GUO
      Slag/metal separation process of the highly reduced oolitic high-phosphorus iron ore fines was investigated. Samples were prepared using the reduced ore fines (metallization rate: 88%) and powder additives of CaO and Na2CO3. Slag/metal separation behavior tests were conducted using a quenching method and the obtained metal parts were subjected to direct observation as well as microstructure examination with SEM and EDS; iron recovery and phosphorus distribution tests were conducted using a Si-Mo high temperature furnace and the obtained metal parts were examined by ICP-AES analysis and mass measurement. Thermodynamic calculation using coexistence theory of slag structure was also performed. Results show that temperature for slag/metal separation must be higher than 1823 K and a satisfying slag/metal separation of the highly reduced ore fines needs at least 4 min; phosphorus content of hot metal is mainly determined by thermodynamics; temperature of 1823–1873 K and Na2CO3 mixing ratio of about 3% are adequate for controlling phosphorus content to be less than 0.3 mass% in hot metal; temperature, time and Na2CO3 mixing ratio do not have significant effect on iron recovery, and iron recovery rate could be higher than 80% as long as a good slag/metal separation result is obtained.


      PubDate: 2014-11-07T15:36:09Z
       
  • Magnetic Properties of FeSiBC Amorphous Alloy Powder Cores Using
           Mechanical-crushed Powder
    • Abstract: Publication date: November 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 11
      Author(s): Xiang-yue WANG , Zhi-chao LU , Cao-wei LU , Guang-min LI , De-ren LI
      The FeSiBC amorphous powder cores were fabricated using powders of the FeSiBC amorphous ribbons which were mechanically crushed for a short time, and the relationship between magnetic properties and powder particle sizes was evaluated. The saturation magnetization B s of the amorphous Fe82 SL2B13 C1 alloy was 1. 62 T, which provided a superior dc-bias property for the powder cores. Meanwhile, a stable permeability up to high frequency range over 10 MHz and the low core loss of 400 kW/m3 at f=50 kHz and B m= 0.1 T were obtained. These excellent high-frequency magnetic properties of the FeSiBC amorphous powder cores could be attributed to the effective electrical insulation between the FeSiBC amorphous powders made by mechanical crushing.


      PubDate: 2014-11-07T15:36:09Z
       
  • Microstructure and Mechanical Properties of Ductile Cast Iron in Lost Foam
           Casting with Vibration
    • Abstract: Publication date: November 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 11
      Author(s): Bo-tao XIAO , Zi-tian FAN , Wen-ming JIANG , Xin-wang LIU , Wei LONG , Qiang HU
      The microstructures and mechanical properties of the ductile cast iron (Dl) specimens obtained by lost foam casting (LFC) with and without vibration were investigated. The results indicate that the number of the graphite nodule increases from 173 mm−2 of the specimens produced by LFC without vibration to 334 mm−2 of the specimens produced by LFC with vibration, and the thickness of the ferrite shell increases. Meanwhile, the amount of the carbides decreases in the specimens produced by LFC with vibration and the granule structure then forms. These are mainly attributed to the “crystal shower” caused by the vibration. In addition, the tensile strength and elongation of DI specimens produced by LFC with vibration are improved due to the dispersion-strengthening of refined carbide and pearlite colony, uniform distribution of the graphite nodule, and increase of the amount of dimples and tearing edges.


      PubDate: 2014-11-07T15:36:09Z
       
  • Numerical Simulation of Microstructure Evolution for SA508-3 Steel during
           Inhomogeneous Hot Deformation Process
    • Abstract: Publication date: November 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 11
      Author(s): Da-shan SUI , Fei CHEN , Pei-pei ZHANG , Zhen-shan CUI
      Based on hot compression tests by a Gleeble-1500D thermo-mechanical simulator, the flow stress model and microstructure evolution model for SA508-3 steel were established through the classical theories on work hardening and softening. The developed models were integrated into 3D thermal-mechanical coupled rigid-plastic finite element software DEFORM3D. The inhomogeneous hot deformation (IHD) experiments of SA508-3 steel were designed and carried out. Meanwhile, numerical simulation was implemented to investigate the effect of temperature, strain and strain rate on microstructure during IHD process through measuring grain sizes at given positions. The simulated grain sizes were basically in agreement with the experimental ones. The results of experiment and simulation demonstrated that temperature is the main factor for the initiation of dynamic recrystallization (DRX), and higher temperature means lower critical strain so that DRX can be facilitated to obtain uniform fine microstructure.


      PubDate: 2014-11-07T15:36:09Z
       
  • Dynamic Recrystallization Behavior of GCr15SiMn Bearing Steel during Hot
           Deformation
    • Abstract: Publication date: November 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 11
      Author(s): Dan ZHANG , Ya-zheng LIU , Le-yu ZHOU , Qiang HAN , Bo JIANG , Zhong-zhi LI
      The hot deformation behavior of GCr15SiMn steel was studied through high temperature compression tests on the Gleeble-1500 thermal-mechanical simulator. The initiation and evolution of dynamic recrystallization (DRX) were investigated with microstructural analysis and then the process variables were derived from flow curves. In the present deformation conditions, the curves of strain hardening exponent (n) and the true strain (ɛ) at the deformation temperature of 1423 K and strain rates of 0.1, 1 and 10 s−1 exhibit single peak and single valley. According to Zener-Hollomon and Ludwik equation, the experimental data have been regressed by using linear method. An expression of Z parameter and hot deformation equation of the tested steel were established. Moreover, the Q values of GCr15SiMn and GCr15 steels were compared. In order to determine the recrystallization fraction under different conditions, the volume fraction of DRX as a function of process variables, such as strain rate (ɛ), temperature (T), and strain (ɛ), was established. It was found that the calculated results agreed with the microstructure of the steel at any deformation conditions.


      PubDate: 2014-11-07T15:36:09Z
       
  • Combustion Property and Kinetic Modeling of Pulverized Coal Based on
           Non-isothermal Thermogravimetric Analysis
    • Abstract: Publication date: November 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 11
      Author(s): Jiu-gang SHAO , Jian-liang ZHANG , Guang-wei WANG , Zhe WANG , Hong-wei GUO
      Non-isothermal combustion kinetics of two kinds of low volatile pulverized coals (HL coal and RU coal) were investigated by thermogravimetric analysis. The results show that the combustibility of HL coal was better than that of RU coal, and with increasing heating rate, ignition and burnout characteristics of pulverized coal were improved. The volume model (VM), the random pore model (RPM), and the new model (NEWM) in which the whole combustion process is considered to be the overlapping process of volatile combustion and coal char combustion, were used to fit with the experimental data. The comparison of these three fitted results indicated that the combustion process of coal could be simulated by the NEWM with highest precision. When calculated by the NEWM, the activation energies of volatile combustion and coal char combustion are 130.5 and 95.7 kJ · mol−1 for HL coal, respectively, while they are 114.5 and 147.6 kJ · mol−1 for RU coal, respectively.


      PubDate: 2014-11-07T15:36:09Z
       
  • Influence of Inclusion on Corrosion Behavior of E36 Grade Low-alloy Steel
           in Cargo Oil Tank Bottom Plate Environment
    • Abstract: Publication date: November 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 11
      Author(s): Hui-bin WU , Jin-ming LIANG , Di TANG , Xiao-tong LIU , Peng-cheng ZHANG , Yuan-jie YUE
      Corrosion behavior of low-alloy steel was investigated in simulated cargo oil tank (COT) bottom plate service environment (10% NaCl solution, pH = 0.85). The corrosion behavior of inclusion was studied by in-situ scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). It was found that pitting corrosion was inclined to occur around the place where inclusions exist. After initial corrosion, an area of 10–20 μm in diameter was formed as a circinate cathode around the edge of inclusion. MnS inclusion dissolved in the simulated COT corrosion solution before low-alloy steel matrix, and pitting was formed at the place where MnS dissolved. TiO2 inclusion dissolved in the simulated COT corrosion solution after low-alloy steel matrix, and pitting was formed at the place where steel matrix dissolved. The corrosion tended to occur at the area where the curvature radius of inclusion is smaller. The size of round TiO2 inclusions had little influence on corrosion behavior in this certain environment.


      PubDate: 2014-11-07T15:36:09Z
       
  • Effect of Heat Treatment on Corrosion Behaviour of Amorphous Metal Fibers
    • Abstract: Publication date: November 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 11
      Author(s): Zhong-wang WU , Zhi-chao LU , Xiao-jun NI , De-ren LI , Shuo FENG , Yuan-hong QI
      Amorphous metal fiber has high corrosion resistance and excellent mechanical properties, making it a kind of good material for reinforcing concrete matrix. The effect of heat treatment on the corrosion behaviour of Fe73-Cr6C9Si1P11 amorphous metal fibers in 0.5 mol/L H2SO4 solution was investigated by electrochemical polarization analysis. Differential scanning calorimetry (DSC) was used to measure the thermal properties. The evolution of the crystallization process after heat treatment was identified by X-ray diffraction (XRD). The results show that the a-Fe. Fe2 P and Fe3 P crystalline phases individually precipitate in the amorphous matrix with increasing annealing temperature. The as prepared amorphous sample shows high corrosion resistance with a lower passivation current density and a wider passive region. The corrosion resistance dramatically decreases after the annealing temperature is higher than 400 °C.


      PubDate: 2014-11-07T15:36:09Z
       
  • Hot Deformation Behavior of F6NM Stainless Steel
    • Abstract: Publication date: November 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 11
      Author(s): Long-teng MA , Li-min WANG , Zheng-dong LIU , Gang YANG , Lun LU , Meng-clu PENG
      The hot deformation behavior of F6NM stainless steel was investigated by hot compression test in a Gleeble-1500D thermal-mechanical simulator. The flow strain-stress curves were obtained and the corresponding metallographic observation of this steel under different deformation conditions was also carried out. This steel exhibited dynamic recrystallization (DRX) in the temperature range of 1273–1473 K and the strain rate range of 0. 01–0.1 s−1. The activation energy for hot deformation was determined to be 457. 91 kJ/mol, and the hot deformation equations were also established. The flow instability zone was determined and could be divided into two regions. The first one was located in the temperature range of 1173–1318 K and the strain rate range of 0.056–10 s−1, while the second one is in the temperature range of 1398–1448 K and the strain rate range of 1.25–10 s−1. In the end, the optimum conditions for hot working were provided.


      PubDate: 2014-11-07T15:36:09Z
       
  • A Mathematical Model to Characterize RH Desulfurization Process
    • Abstract: Publication date: November 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 11
      Author(s): Hong-bo YANG , Shu-feng YANG , Jing-she LI , Jiang-shan ZHANG
      A physical model based on similarity principles was built to simulate RH desulfurization process. In order to quantitatively analyze RH desulfurization process, a mathematical model was proposed. By analyzing experimental results with the mathematical model, an empirical formula whose determination coefficient was 0.98 was given to express the relationship between transient desulfurization efficiency and time. All the determination coefficients of four fitted curves based on four repeated experiments with different gas flow rates were more than 0.91, which was the exact evidence of the rationality of the empirical formula. Meanwhile, it was found that transient desulfurization ability increased firstly and then decreased with increasing gas flow rate and reached the maximum value when the gas flow rate was 1.8 m3/h. A plenty of repeated trials showed the same rule, which validated the mathematical model and the conclusions obtained from physical experiments.


      PubDate: 2014-11-07T15:36:09Z
       
  • Effect of Iron Oxides on Activity of Calcium Aluminate Clinker in
           CaO-Al2O3-SiO2 System
    • Abstract: Publication date: November 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 11
      Author(s): Hai-yan YU , Xiao-lin PAN , Bao-wei LIU , Bo WANG , Shi-wen BI
      The sintering characteristics at 1350 °C and leaching property at 80 °C of calcium aluminate clinkers in the CaO-Al2O3-SiO2 (C-A-S) system with different additions of FeO and Fe2O3 were investigated. FeO inhibits the conversion of β-Ca2SiO. to γ-Ca2SiO4 and makes the clinker not pulverizable. FeO and Fe2O3 inhibit the formation of CaAl2O4, but promote the formation of Ca12Al14O33. The interplanar spacing at (2 1 1) crystal face of Ca12Al14O33 in the clinker increases with the increase of FeO addition, which indicates that FeO forms solid solutions in Ca12Al14O33. The clinkers with Fe2O3 addition form a new phase Ca2 Fe2O3, and the amount of Ca2 Fe2O3 increases with the increase of Fe2O3 addition. Both FeO and Fe2O3 do not affect the Al2O3 leaching rate of calcium aluminate clinker in sodium carbonate solution, but they increase the molar ratio of caustic Na2O to Al2O3 in the leached liquor.


      PubDate: 2014-11-07T15:36:09Z
       
  • Quantitative Evaluation Method of Shape Indicator for Cold-rolled Strip
    • Abstract: Publication date: November 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 11
      Author(s): Li-po YANG , Bing-qiang YU , Hua-xin YU , Chang-zheng DU
      Quantitative level evaluation of cold-rolled strip was significant for the shape control and the product structure optimization. Based on the probability statistics method and the shape pattern recognition method, the shape evaluation model of cold-rolled strip was established to evaluate real-time shape of the online strip. The model was embedded in the shape control system, and the online strip shape state was real-time observed whether to meet the technical indicators, so the shape level could be identified and evaluated. Based on the shape evaluation indicators, the shape component could be well controlled to improve the shape hit rate and the control stability, so that the rolled strip shape could meet the technical requirements. At a 1050 cold strip mill, the shape data of the scene typical specifications strip were online collected and real-time evaluated, and the hit of macro shape in less than 8 I was 68.44%, indicating that the mill shape control had considerable room for improvement, as well as the evaluation method was feasible and practical for quantitative evaluation of the strip shape. So the new evaluation model has important guiding significance to increase value-added and reduce product quality objection.


      PubDate: 2014-11-07T15:36:09Z
       
  • Influence of Oxide Morphologies on Galvanizability of Third Generation
           Automotive Steel
    • Abstract: Publication date: November 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 11
      Author(s): She-ming JIANG , Shi-jie FENG , Xun-hua YUAN , Yuan-peng LI , Zhen-hua LI , Qi-fu ZHANG
      Focusing on improving the galvanizability of the third generation automotive steel, the effect of surface oxide morphologies on the galvanizability was studied. The results show that the surface oxide types of sample steels by X-ray photoelectron spectroscopy (XPS) analysis after annealing in different conditions are the same. Only MnO, MnO2 and Cr2O3 were detected and no complex oxide exists on the surface. Morphologies of surface oxides can greatly influence the galvanizability of the third generation automotive steel. Nodule-like oxide surface can contribute to better wettability and inhibition layer than vitreous film-like oxide surface. Galvanized panels of nodule-like oxide surface steels only show pinhole-sized bare spots, while panels galvanized from vitreous film-like oxide surface steels reveal larger areas of bare spots and uncoated areas. Inhibition layer observed in galvanized panels of nodule-like oxide surface steels is compact but not homogeneous; some inhibition layer grains are fine, and others are coarse, while the inhibition layer grains of panels galvanized from vitreous film-like oxide surface steels have a non-compact morphology with some particularly fine equiaxed crystals which developed deficiently.


      PubDate: 2014-11-07T15:36:09Z
       
  • Optimization of Hot Workability in Superaustenitic Stainless Steel 654SMO
    • Abstract: Publication date: October 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 10
      Author(s): En-xiang PU , Wen-jie ZHENG , Zhi-gang SONG , Jin-zhong XIANG , Xian-ping WEI
      Hot compression tests were conducted on a Gleeble-3800 machine in a temperature range of 950 to 1200 °C and a strain rate range of 0.001 to 10 s−1 in order to study the hot deformation behaviour of superaustenitic stainless steel 654SMO. The results show that peak stress increases with decreasing temperature and increasing strain rate, and the apparent activation energy of this alloy was determined to be about 494 kJ/mol. The constitutive equation which can be used to relate the peak stress to the absolute temperature and strain rate was obtained. The processing maps for hot working developed on the basis of flow stress data and the dynamic materials model were adopted to optimize the hot workability. It is found that the features of the maps obtained in the strain range of 0.2 to 1.0 are fundamentally similar, indicating that the strain does not have a substantial influence on processing map. The combination of processing map and microstructural observations indicates that the favorable hot deformation conditions are located in two domains of processing map. The first domain occurs in the temperature range of 980 to 1035 °C and strain rate range of 0.001 to 0.01 s−1 with a peak efficiency of 55%. The second domain appears in the temperature range of 1120 to 1180 °C and strain rate range of 0.3 to 3 s−1 with peak efficiency of 35%. Compared to other stable domains, the specimens deformed in these two domains exhibit full dynamic recrystallization grains with finer and more uniform sizes. An instability domain occurs at temperatures below 1100 °C and strain rate above 0.1 s−1, and flow instability is manifested in the form of flow localization.


      PubDate: 2014-10-10T19:48:02Z
       
  • Structure Model of Granules for Sintering Mixtures
    • Abstract: Publication date: October 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 10
      Author(s): Li-shun YUAN , Xiao-hui FAN , Min GAN , Gui-ming YANG , Yi WANG
      Structure model of granules, boundary value of nucleus and powder, and the relationship between granulation efficiency and boundary value were investigated. Granules of sintering mixtures are composed of adhesive powder and nucleus. In the mixtures, particles larger than 1.00 mm act as nucleus and particles smaller than 0.25 mm act as adhesive powder. Particles with size between 0.25–1.00 mm can be adhesive powder as well as nucleus depending on the granulation conditions. When the boundary value is close to 0.25 mm, the granulation efficiency is lower than 50%. When the boundary value is close to 1.00 mm, the granulation efficiency is above 90%. The boundary value is influenced by the iron ore type, granulation moisture, fineness of raw materials and burnt-lime activity. Good adhesive capability, suitable moisture content, appropriate particle size distribution and high burnt-lime activity make the boundary value move towards 1.00 mm and improve the granulation efficiency.


      PubDate: 2014-10-10T19:48:02Z
       
  • Wear Resistance and Bond Strength of Plasma Sprayed Fe/Mo Amorphous
           Coatings
    • Abstract: Publication date: October 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 10
      Author(s): Chao-ping JIANG , Ya-zhe XING , Feng-ying ZHANG , Jian-min HAO , Xu-cling SONG
      Fe-based and Fe/Mo composite amorphous coatings were deposited on the surface of plain carbon steel substrates by atmospheric plasma spraying (APS). With increasing the Mo alloy content, the microstructure of the coatings revealed more dense structure. The porosities of composite coating were all less than those of Fe-based coating due to Mo alloy self-bonding performance. The ME-10 friction and wear tester was employed to investigate the wear behaviors of the coatings under dry sliding conditions. It was found that the mass loss of the resultant coatings decreased with increasing Mo-based powders into the feedstock. This was attributed to the reduction of the delaminations resulting from improved intersplat bond with Mo addition.


      PubDate: 2014-10-10T19:48:02Z
       
  • Growth Kinetics of Proeutectoid Ferrite in an Fe-0. 09C-1. 5Mn-0. 2Si
           Steel
    • Abstract: Publication date: October 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 10
      Author(s): Lin CHENG , Kai-ming WU , Xiang-liang WAN , Guo-hong ZHANG
      Growth kinetics of proeutectoid ferrite, including grain boundary face nucleated ferrite, grain boundary edge nucleated ferrite allotriomorph and intragranular ferrite idiomorph, were experimentally measured in an Fe-0. 09C-1. 5Mn-0. 2Si steel and compared with theoretical calculation in local equilibrium and paraequilibrium modes. Grain boundary edge nucleated ferrite exhibited larger growth rate than grain boundary face nucleated ferrite and intragranular ferrite idiomorph. Experimental kinetics of proeutectoid ferrite was within the window defined by the local equilibrium and paraequilibrium limits. A transition of growth kinetics from paraequilibrium to local equilibrium was observed in the temperature range of 650–750 °C, which can be explained in terms of solute drag.


      PubDate: 2014-10-10T19:48:02Z
       
  • Hydrogen Absorption and Desorption during Heat Treatment of AISI 4140
           Steel
    • Abstract: Publication date: October 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 10
      Author(s): Ming-da ZHANG , Mao-qiu WANG , Han DONG
      Hydrogen plays an important role in the formation of quench cracks of structural steels. To clarify hydrogen absorption and desorption during heat treatment of AISI 4140 steel, thermal desorption spectrometry (TDS) analysis was carried out for the specimens in the as-rolled, as-quenched, and quenched and tempered conditions. Results show that hydrogen content increased from 0.127×10−6 in the as-rolled specimen to 0.316×10−6 in the as-oil-quenched specimen. After tempering at 200 °C, the hydrogen content in the oil-quenched specimen decreased to 0.155×10−6, and the peak temperature of hydrogen desorption increased from 200 to 360 °C. From the dependence of hydrogen content in the as-quenched specimens on austenitizing time, it can be deduced that hydrogen absorption occurs during austenitizing. The simulation of hydrogen absorption contributes to a better understanding on the distribution of hydrogen during the heat treatment in structural steels.


      PubDate: 2014-10-10T19:48:02Z
       
  • High Temperature Oxidation Resistance of 9Ni Steel
    • Abstract: Publication date: October 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 10
      Author(s): Yi-zhi LIU , Cai-fu YANG , Feng CHAI , Tao PAN , Hang SU
      Oxidation rates and scale/steel interface configuration of 9Ni steels were investigated at 1000–1250 °C in air. The results revealed that Cu addition caused high temperature oxidation resistance to deteriorate. High temperature oxidation rates increased and scale/steel interface configuration became complicated due to Cu addition. Scale/steel interface appeared to be network above certain temperature. Temperature required to form network scale/steel interface dropped more than 100 °C for 1.5% Cu-containing steel. (Fe, Ni, Cu) x O y in inner oxidation layer dissociated to Fe-Ni-Cu phase and released active oxygen which can react with base steel easily. So the inner oxidation layer became the second source of oxidizing agent besides atmosphere. Internal stress at austenite grain boundary caused local oxide to fragment. So the scale/steel interface appeared to be network. Liquid Si-rich phase formed at sufficiently high temperature. Penetration of the liquid Si-rich phase along austenite grain enhanced austenite grain oxidizing.


      PubDate: 2014-10-10T19:48:02Z
       
  • Characteristics of Precipitation in an As-cast Nb- and V-containing High
           Nitrogen CrMn Austenitic Steel
    • Abstract: Publication date: October 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 10
      Author(s): Zhong-ping SHI , Zhen-hua WANG , Shu-hua SUN , Ze-an ZHOU , Ying-ping GUAN , Wan-tang FU
      The phase diagram of an Nb- and V-containing 18Mn18Cr0. 5N steel was investigated using thermodynamic calculation. The compositions and characteristics of precipitates were investigated by scanning electron microscopy, energy dispersive spectrometry, X-ray diffraction, and differential scanning calorimetry. Under equilibrium conditions, MX precipitates at 1350 °C. MX is a substitutional solid solution of Nb4 N3.38, and its composition (at. %) is approximately: Nb 40, N 40, V 8, and Fe, Cr, and Mn balance. The precipitates, with shapes including irregular bulk, rod, and ellipsoid, are primarily distributed at grain boundaries and triple junctions, and their size is approximately 5–10 μm. Finally, the microalloying of high nitrogen CrMn austenite steels, control of precipitate size, and the effect of precipitate on hot forming were discussed.


      PubDate: 2014-10-10T19:48:02Z
       
  • Shear Fracture of Advanced High Strength Steels
    • Abstract: Publication date: October 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 10
      Author(s): Sheng HUANG , Yi-xi ZHAO , Chun-feng HE
      Failure experiments were carried out through a stretch-bending test system for advanced high strength steels, i.e. dual-phase (DP) steels and martensitic steels (MS). The die radius in this system was designed from 1 to 15 mm to investigate the failure mode under different geometries. Two failure modes were observed during the experiments. As a result, critical relative radii (the ratio of inner bending radius R to sheet thickness t) for DP590 and DP780 steels were obtained. The stretch-bending tests of DP980 display some trends unlike DP590 and DP780 steels, and curve of DP980 in different thicknesses does not coincide well. High blank holder force exhibits more possibility of shear fracture tendency than low blank holder force. The unique character of high strength martensitic steel (1500MS) is that no shear fracture is found especially over small bending radius (R = 2 mm) under the same experimental conditions. Microstructure analysis indicates that there are obviously elongated grains on shear fracture surface. It shows smaller diameter and shallower depth of the dimples than the necking failure.


      PubDate: 2014-10-10T19:48:02Z
       
  • Ductile Fracture Prediction of 316LN Stainless Steel in Hot Deformation
           Process
    • Abstract: Publication date: October 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 10
      Author(s): Jian-li HE , Juan LIU , Zhen-shan CUI , Chao-zhong YANG , Fei CHEN
      A ductile fracture criterion of 316LN stainless steel, combined with the plastic deformation capacity of material and the stress state dependent damages, was proposed to predict ductile fracture during hot deformation. To the end, tensile tests at high temperatures were first performed to investigate the fracture behavior of 316LN stainless steel. The experimental results show the variation of the critical fracture strain as a function of temperature and strain rate. Second, the criterion was calibrated by using the upsetting tests and the corresponding numerical simulations. Finally, the proposed fracture criterion was validated by the designed tests and the corresponding finite element (FE) simulation. The results show that the criterion can successfully predict the onset of ductile fracture at elevated temperatures.


      PubDate: 2014-10-10T19:48:02Z
       
  • Interface-correlated Characteristics of Stainless Steel/Carbon Steel Plate
           Fabricated by AAWIV and Hot Rolling
    • Abstract: Publication date: October 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 10
      Author(s): Qing-xue HUANG , Xiao-rong YANG , Li-feng MA , Cun-long ZHOU , Guang-ming LIU , Hai-bing LI
      Stainless steel (SS)/carbon steel (CS) clad plates were generated by means of the all-around weld of interface and vacuuming (AAWIV) followed by hot rolling, wherein AAWIV was utilized for controlling the interface oxidation during hot rolling. The structure near the interface was analyzed by optical microscopy (OM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The mechanical properties of SS/CS clad plates were investigated by tensile and shear as well as bend tests. The SS/CS interface is relatively flat and no visible separation appears. Line scanning analysis shows that diffusion of Cr and Ni from SS to CS and C from CS to SS occurred during bonding. Higher dislocation densities are observed in both layers of parent plates adhering to the interface. The SS/CS clad plates reveal higher yield, tensile and shear strengths. Both macroscopic delamination at the interface and fracture of base CS as well as intergranular fracture appearance of flyer plate are observed in the tensile test. The shear specimen fails in a ductile manner and the bend specimen tested shows no visible crack at the interface. Taking both interfacial structure and mechanical properties into account, the SS/CS clad plates exhibit sound bonding by the process of AAWIV and hot rolling.


      PubDate: 2014-10-10T19:48:02Z
       
  • Effect of Actual Cooling Rate of Ladle Stream on Persistent Metallurgical
           Performance of a Given Tundish
    • Abstract: Publication date: October 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 10
      Author(s): Hai-bo SUN , Jia-quan ZHANG
      To evaluate the effect of actual cooling rate of liquid steel in the ladle on the metallurgical performances of a tundish, a transient and coupled computational model was developed to reveal the flow fields, temperature fields, residence time distribution of the molten steel and the inclusion removal efficiency in a typical single-strand tundish with given geometry and process parameters. The results showed that, with the decrease of the ladle stream cooling rate, the temperature difference of bulk flow at the outlet of tundish over a normal casting period decreased from 11.3 to 2.6 K, and the dead volume fraction of the tundish decreased from 17.58% to 14.35%, while the inclusion removal efficiency was increased especially for the inclusions with the diameter less than 50 μm, whose removal ratio could be increased by 20.62%. When the cooling rate was less than 0.3 K · min−1, however, the variation rates of the three evaluation criterions above declined significantly, which suggested that a critical value existed for the effect of the cooling rate of ladle stream on the tundish performances. The establishment of the critical ladle stream cooling rate should be very important to achieve persistent metallurgical properties of tundish over the whole casting stage, together with the reasonable ladle insulation design.


      PubDate: 2014-10-10T19:48:02Z
       
  • Experimental Study and Thermodynamic Optimization of the FeO-V2O3 System
    • Abstract: Publication date: October 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 10
      Author(s): Li ZENG , Yu WANG , Li-kai FAN , Bing XIE
      Optimization of the phase diagram of FcO-V2O3 system is a part of an on-going research project to develop a self-consistent multi-component thermodynamic database for vanadium slag from hot metal. Due to the lack of experimental data for optimization, a novel experimental investigation has been carried out by thermal analysis (DSC) with a series of slags on different V2O3 contents (i.e. 3mass %–12mass%). All available thermodynamic and phase diagram data for the binary systems have been simultaneously optimized with CALPHAD (Calculation of Phase Diagrams) methods to give one set of model equations for the Gibbs free energy of the liquid slag as functions of composition and temperature. The modified quasi-chemical model was used to describe the binary slag system. It was demonstrated that the calculated phase diagram with the optimized parameters was in good agreement with the experimental data.


      PubDate: 2014-10-10T19:48:02Z
       
  • Thermogravimetric Analysis of Coal Char Combustion Kinetics
    • Abstract: Publication date: October 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 10
      Author(s): Guang-wei WANG , Jian-liang ZHANG , Jiu-gang SHAO , Hui SUN , Hai-bin ZUO
      Four chars prepared from pulverized coals were subjected to non-isothermal and isothermal combustion tests in a thermogravimetric analysis (TGA) device. Three different test methods, i.e., non-isothermal single heating rate (A), non-isothermal multiple heating rate (B), and isothermal test (C), were conducted to calculate the kinetic parameters of combustion of coal char. The results show that the combustion characteristics of bituminous coal char is better than that of anthracite char, and both increase of heating rate and increase of combustion temperature can obviously improve combustion characteristics of coal char. Activation energies of coal char combustion calculated by different methods are different, with activation energies calculated by methods A, B and C in the range of 103. 12–153. 77, 93. 87–119. 26, and 46. 48–76. 68 kJ/mol, respectively. By using different methods, activation energy of anthracite char is always higher than that of bituminous coal char. In non-isothermal tests, with increase of combustion temperature, the combustion process changed from kinetic control to diffusion control. For isothermal combustion, the combustion process was kinetically controlled at temperature lower than 580 °C for bituminous coal char and at temperature lower than 630 °C for anthracite char.


      PubDate: 2014-10-10T19:48:02Z
       
  • Spatial Vibration and Its Numerical Analytical Method of Four-high Rolling
           Mills
    • Abstract: Publication date: September 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 9
      Author(s): Yong-jiang ZHENG , Guang-xian SHEN , Yi-geng LI , Ming LI , Hong-min LIU
      The rolls in contemporary four-high mills cannot be maintained parallel during the rolling process. Therefore, four-high rolling mill vibrations take place in six degree of freedom (DOF) leading to spatial behaviors involving vertical, horizontal, axial, torsional, cross and swinging vibration modes resulting in complex relative motions between the rolls. Two numerical methods, modified Riccati-transfer matrix method (Riccati-TMM) and finite element method (FEM), are presented to analyze a spatial vibration characteristic of two four-high rolling mills with different stability. The natural frequency and mode shape of four-high rolling mills are obtained, and the clearance has a great effect on natural frequency and mode shape. In addition, field testing experiment is also conducted to measure natural frequency by power spectrum analysis of rolling mill vibration. Experimental results basically agree with those calculated by Riccati-TMM and FEM, which means that the Riccati-TMM and the FEM can be used for analysis of spatial vibration of four-high rolling mill. Meanwhile, the spatial vibration shows more compound vibration behaviors and the negative effect of horizontal, vertical, cross and swinging vibration modes are effectively controlled after redesign of rolling mill. These advantages have a great significance for the rolling mill to be operated with a much higher rolling speed and improved yield of products.


      PubDate: 2014-09-16T11:51:16Z
       
  • Modeling and Analysis of Interstand Tension Control in 6-high Tandem Cold
           Rolling Mill
    • Abstract: Publication date: September 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 9
      Author(s): Xin ZHANG , Shu-zong CHEN , Hao-yuz ZHANG , Xi-wen ZHANG , Dian-hua ZHANG , Jie SUN
      The interstand tension control is one of the most important ways to meet tight tolerances for strip product quality during tandem cold rolling process. Using coordinate analysis and parabolic approximation for the mass flow balance principle, the strip velocities eliminating the use of forward slips and backward slips were calculated. In order to reduce the effect of roll eccentricity on the tension measurement, a filter based on bilinear transformation was designed. Applying a first-order Taylor series approximation, the transfer function matrix model of interstand tension stress was derived. The actual measurements on-site and the final calculation results showed that the established model had high calculation accuracy and was beneficial for interstand tension control of tandem cold rolling process.


      PubDate: 2014-09-16T11:51:16Z
       
  • Principle of Multi-roller Straightening Process and Quantitative
           Resolutions of Straightening Strategies
    • Abstract: Publication date: September 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 9
      Author(s): Jing YIN , Jun ZHAO , Shi-yan WANG , Xian-song WAN , Yue-lin LI
      The multi-roller straightening process of section steel is analyzed by the springback theory of small curvature plane bending. The theoretical analysis results prove the curvature unification in straightening process and clearly reveal the principle of the multi-roller straightening process. The principle can be described as: the initial curvatures are reduced by several times anti-bending; meanwhile the initial curvature differences are diminished and the residual curvatures are unified; finally, the member after curvature unification is straightened by the last anti-bending. With the plastic region ratios becoming larger, the initial curvatures are more easily unified in straightening process. Based on the plastic region ratios and the required number of roller systems for unifying the initial curvatures, the large deformation straightening strategy and the small deformation straightening strategy are redefined. The new definition provides an important theoretical basis for setting reliable reduction rules. Through the theoretical analysis results, a new straightener design philosophy is proposed to improve the straightening quality and further increase the adjustment precision as well as the flexibility of the last roller system. The adjustable end roller emerges as the times required, achieving a good effect in practical application.


      PubDate: 2014-09-16T11:51:16Z
       
  • Study and Application of Camber Control Model of Intermediate Slab in
           Rough Rolling
    • Abstract: Publication date: September 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 9
      Author(s): Hai-yu WANG , Quan YANG , Xiao-chen WANG , Feng HE , Yu-feng CHEN
      In order to solve the camber problem of intermediate slab in a domestic conventional hot rolling mill, a three-dimensional elastic-plastic dynamic model was built through finite element method to quantitatively calculate the influence of lateral flow factors in different entry thicknesses, reductions, reduction ratios differences on both sides and width factors. Thus, the extending difference at outlet of intermediate slab in length was transformed into thickness difference on both sides by the results, and then the tilting value of roll gap reduction to control the camber was calculated. Based on the above results, the camber control model of intermediate slab in rough rolling was established. The practical application on the rough rolling mill obtained a decent control effect, and it proved that this model had a high accuracy.


      PubDate: 2014-09-16T11:51:16Z
       
  • Experimental and Simulation Studies on Fabricating GCr15/40Cr Bimetallic
           Compound Rollers Using Electroslag Surfacing with Liquid Metal Method
    • Abstract: Publication date: September 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 9
      Author(s): Lei RAO , Shuang-jun WANG , Jian-hua ZHAO , Mao-peng GENG , Gang DING
      Electroslag surfacing with liquid metal (ESSLM) is an excellent method for producing high-quality bimetallic compound rollers. The quality of each compound roller is primarily determined by the metallurgical quality of the combined interface. A GCr15/40Cr compound roller is produced using an ESSLM non-consumable electrode electroslag heating method. The temperature and electric fields produced by the ESSLM system are calculated. As the roller core moves downward in the mold, it passes through five sections: the preheating section, the rapid heating section, the temperature homogenizing section, the bimetal fusing section and the cooling section which listed from the top to bottom of the mold, respectively. The temperature distribution and the degree of the surface temperature fluctuation in the roller core are different for each section. Near the combined interface, four layers are found from the roller core to the cladding layer: the remelting layer, the fusion layer, the interface solidification layer and the chilling layer, respectively. Among these, the fusion and interface solidification layers are the key transition zones that greatly influence the combination quality. The surface temperature of the roller core prior to cladding is mainly determined by the drawing velocity, and the thickness of the transition layer increases as the drawing velocity decreases. A transition layer that is too thick or too thin will reduce the mechanical properties at the combined interface. Therefore, the drawing velocity should be limited to a moderate range to produce a satisfactory bimetallic compound roller.


      PubDate: 2014-09-16T11:51:16Z
       
  • Healing Behavior of Micropores in Powder Metallurgy 316L Stainless Steel
           during Hot Forging and Heat Treatment
    • Abstract: Publication date: September 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 9
      Author(s): Ying KAN , Shi-hong ZHANG , Li-wen ZHANG , Ming CHENG , Hong-wu SONG , Hong-wei LU
      The healing behavior of micropores in powder metallurgy (P/M) 316L stainless steel during hot forging and subsequent heat treatment was studied. The results showed that hot forging can improve the homogeneity of the pore size and enhance the relative density of material in varying degree due to different forging temperatures. As a result of deformation and diffusion bonding at high temperature, the irregular pores were spheroidized and finally turned into stable inner grain pores. The comparison of compression behavior between P/M and wrought dense materials has shown that the pores can either be the obstacles of dislocation movement or be the nucleation sites accelerating the recrystallization according to the difference of deformation temperatures.


      PubDate: 2014-09-16T11:51:16Z
       
  • Migration of δ/γ Interface in Low Carbon Steels during
           Continuous Cooling
    • Abstract: Publication date: September 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 9
      Author(s): Qing-chun LI , Yong-feng QI , Shu XU , Chao WANG , Guo-wei CHANG
      The δ-ferrite to γ-austenite phase transformation process of low carbon steel was observed in-situ under a confocal scanning laser microscope and the influence of manganese and chromium on the migration of δ/γ interphase boundary during the δ to γ phase transformation was studied. It was found that the δ/γ interphase boundary becomes unstable with the decrease of temperature, from planar to curved morphology during the δ to γ phase transformation of Fe-0. 08C steel and Fe-0. 08C-0. 8Mn steel. But in Fe-0.08C-0.8Cr steel, the δ/γ interphase boundaries are stable with planar morphology during the whole δ-ferrite to γ-austenite transformation. The destabilization of δ/y interphase boundary in Fe-0. 08C and Fe-0. 08C-0. 8Mn steels results from high degree of supercooling and sub-boundaries in γ, respectively. The stabilization of δ/γ interphase boundary in Fe-0. 08C-0. 8Cr steel results from the slow diffusion rate of carbon atom induced by the addition of chromium.


      PubDate: 2014-09-16T11:51:16Z
       
  • Texture, Grain Boundary Characterization and Segregation of Phosphorus in
           an Annealed Interstitial Free Steel
    • Abstract: Publication date: September 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 9
      Author(s): Xin-li SONG , Kun PENG , Ze-xi YUAN , Juan JIA , Jing LIU , Li-xia FAN
      The {111} // ND plane texture, grain boundary characterization and grain boundary segregation of phosphorus are investigated for the phosphorus added high strength interstitial free (IF) steel annealed at 810 °C for 60 s to 180 s. The results show that the maximum volume fraction of {111} // ND plane texture is about 85% and the grain boundary segregation peak of phosphorus is about 14 at. % for the steel annealed at 810 °C for 120 s. The Σ3 and other low-ΣCSL (coincident site lattice) boundaries are lowest for the steel annealed for 120 s. Segregation of phosphorus is also found at low angle grain boundaries.


      PubDate: 2014-09-16T11:51:16Z
       
  • Sintering Behavior of Porous Titanium Fiber Materials
    • Abstract: Publication date: September 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 9
      Author(s): Shi-feng LIU , Zheng-ping XL , Hui-ping TANG , Xin YANG , Zhao-hui ZHANG , Quan-ming LIU
      The porous titanium fiber materials with open porosity were successfully prepared by the vacuum sintering technology. The morphology characteristics of sintering neck of porous titanium fiber materials were investigated by scanning electron microscopy (SEM). The results show that the formation and growth of sintering neck of porous titanium fiber material approximately follow the rule that the primary mechanism is grain boundary diffusion and subsidiary mechanisms are other diffusion mechanisms during the sintering process. The formation and growth of the sintering neck depend mainly on the sintering temperature and slightly on the soaking time. The sintering system of porous titanium fiber material was determined and the equation of the sintering neck's length was established.


      PubDate: 2014-09-16T11:51:16Z
       
  • Influence of Mo on Growth and Coarsening of Nanometer-sized Carbides in
           Low-alloy Ferritic Steels Containing Ti
    • Abstract: Publication date: September 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 9
      Author(s): Bin-hao HU , Qing-wu CAI , Hui-bin WU
      By optical microscopy, transmission electron microscopy and energy dispersive spectroscopy, the changes with aging time in size, composition and distribution of nanometer-sized (Ti, Mo) C precipitated in Ti-Mo low-alloy ferrite steel have been studied in comparison with that of nanometer-sized TiC precipitated in Ti low-alloy ferrite steel. It was found that the growth rate of (Ti, Mo) C in Ti-Mo steel was less than that of TiC in Ti steel. Nanometersized carbides formed at 650 °C for 550 °C) for 55 h were at transitional stage from growth to coarsening. When aging time reaches 55 h, the coarsening rates of nanometer-sized carbides in Ti and Ti-Mo steel tend to be the same and invariable. The influence of Mo on growth and coarsening of nanometer-sized carbides tends to decrease with increasing aging time, and Mo contents in nanometer-sized carbides with the same size at different aging time were different.


      PubDate: 2014-09-16T11:51:16Z
       
  • Formation of AlN Nano Particles Precipitated in St-14 Low Carbon Steel by
           Micro and Nanoscopic Observations
    • Abstract: Publication date: September 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 9
      Author(s): Amirsalar Khandan , Ebrahim Karamian , Mojdeh Faghih , Allain Bataille
      In low carbon steels, dissolution and precipitation of the second phases such as carbides and nitrides during annealing cycles can affect the final structure and properties of the materials. The interaction of above processes depends on parameters such as reheating temperature, heating rate, annealing temperature, soaking time and finishing temperature in hot rolling stage before cold rolling. The effects of heating rate and annealing temperature on the microstructure and hardness were investigated. Two heating rates for annealing temperatures of 550, 610 and 720 °C were applied on cold-rolled specimens and St-14 low carbon steel, which were immediately quenched after isothermal annealing. The intercept method was used to measure average grain sizes. However, resulted microstructures are different for the two heating rates. While pancaked structures were observed in specimens annealed with low heating rate, in samples annealed with high heating rate, equiaxed microstructures were observed. Vickers micro-hardness values decreased at all temperatures, which were more significant at higher temperatures. At longer annealing time, signs of increase of hardness values were detected. All results and observations consistently suggest that a precipitation process has occurred concurrently with restoration processes during annealing. In addition, the energy dispersive spectroscopy analysis resulted from transmission electron microscopic micrographs have proved that the nano particles precipitated in grain boundaries are AlN.


      PubDate: 2014-09-16T11:51:16Z
       
  • Numerical Analysis of Fluctuation Behavior of Steel/Slag Interface in
           Continuous Casting Mold with Static Magnetic Field
    • Abstract: Publication date: September 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 9
      Author(s): An-yuan DENG , Lin XU , En-gang WANG , Ji-cheng HE
      Utilizing ANSYS CFX commercial software and volume fraction of fluid (VOF) model, fluctuation behavior of steel/slag interface was numerically simulated in continuous casting mold with static magnetic field, and the influence of metal jet characteristics on the behavior of steel/slag interface was investigated. The results indicated that the behavior of steel/slag interface is similar at different process parameters, which is closely related to the characteristic of the flow field. The steel/slag interface has an obvious trough characteristic, which can be divided into three zones: frontal valley zone, back valley zone and horizontal zone; as the magnetic flux density increases, the fluctuation of liquid level increases firstly and then decreases, and a reasonable magnetic flux density can make steel/slag interface obtain a relatively flat interface, which can prevent slag from being entrapped into liquid steel. For a thin slab continuous casting process, when the casting speed is 4 m/min, a reasonable magnetic flux density is about 0.5 T, and the interfacial fluctuation is weaker. No matter the position of magnetic field is horizontal or vertical, for different operating parameters, there is a corresponding reasonable magnetic field position where the steel/slag interface fluctuation can be properly controlled and slag entrapment can be prevented.


      PubDate: 2014-09-16T11:51:16Z
       
  • Surface Nanocrystallization of Nb-Ti Stabilized 439M Ferritic Stainless
           Steel
    • Abstract: Publication date: September 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 9
      Author(s): Yao-chun ZHANG , Chao CHEN , Cheng-jia SHANG , Dong-yang LI
      A new nanocrystallization process was designed, which included punching the surface coating to generate dislocation network or cells and recovery treatment to turn the dislocation cells into nano-sized grains. The effort was made to increase the service life of Nb-Ti stabilized 439M stainless steel surface with medium passive ability, particularly to enhance the outmost surface layer by nanocrystallization for improving resistances to corrosion. Electrochemical properties, electron work functions (EWFs), nano-mechanical properties of the nanocrystallized surfaces were investigated. It was demonstrated that the nanocrystallized 439M stainless steel surface exhibited improved resistance to corrosion in 0. 5 mol/L H2 SO4 solution. However, the nanocrystallized 439M stainless steel surface exhibited decreased resistance to corrosion in 3. 5% NaCl solution.


      PubDate: 2014-09-16T11:51:16Z
       
  • Compressive Behavior of Porous Titanium Fiber Materials
    • Abstract: Publication date: August 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 8
      Author(s): Shi-feng LIU , Zheng-ping XI , Hui-ping TANG , Xin YANG , Zhao-hui ZHANG
      Porous titanium fiber materials with the fiber sizes of 70—120 μm in diameter were prepared by vacuum sintering technology. The morphology and compressive properties of porous titanium fiber materials were investigated by using a scanning electron microscope (SEM) and an MST 858 compression testing machine in quasi-static condition. The results show that porous titanium fibers form complex micro-networks. The stress-strain curves of porous titanium fiber materials exhibit clastic region, platform region and densification region and no collapse during platform region. The yield strength of porous titanium fiber materials decreases with increasing the porosity and increasing the fiber diameter.


      PubDate: 2014-08-16T06:32:32Z
       
  • Effect of Boron on CGHAZ Microstructure and Toughness of High Strength Low
           Alloy Steels
    • Abstract: Publication date: August 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 8
      Author(s): Han YANG , Xi-xia WANG , Jin-bo QU
      Effect of boron on the microstructure and impact toughness in the coarse-grained heat-affected zone (CGHAZ) of two high strength low alloy steels, boron-free and boron-containing, was investigated by means of weld thermal simulation test. The result shows that, for the boron-free steel, a microstructure consisting of grain boundary ferrite degenerates pearlite and granular bainite for longer t 8/5 (the cooling time from 800 to 500 °C), while lath bainite for shorter t 8/5. For the boron-containing steel, granular bainite is dominant for a wide range of t 8/5. Continuous cooling transformation (CCT) study on the CGHAZ indicates that the transformation start temperature decreases by about 50—100 °C under different t 8/5, for the boron-containing steel compared with the boron-free steel. The presence of boron suppresses the nucleation of ferrite at prior austenite grain boundaries and hence enlarges the range of t 8/5 for granular bainite transformation. However, the addition of boron deteriorates the impact toughness of CGHAZ, which may be due to a markedly increased fraction of martensite-austenite (M-A) constituents and decreased fraction of high angle grain boundaries.


      PubDate: 2014-08-16T06:32:32Z
       
  • Numerical Simulation on Blast Furnace Operation with Hot Burden Charging
    • Abstract: Publication date: August 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 8
      Author(s): Tong-lai GUO , Man-sheng CHU , Zheng-gen LIU , Hong-tao WANG
      Blast furnace operation with hot burden charging was numerically simulated to preliminarily analyze its advantages and disadvantages. Multi-fluid blast furnace model was utilized to simulate hot burden charging operations under the conditions that the charging temperatures of pellet and coke were supposed separately or simultaneously as 800 °C. The results showed that, with hot burden charging, the furnace top temperature significantly increased in comparison to the conventional operation with cold burden charging. However, in-furnace temperature decreased, which decelerated the reduction rate of ferrous burdens. The concentrations of reducing gases were decreased in the furnace. The height of cohesive zone shifted downwards. When the charging temperatures of pellet and coke were simultaneously 800 °C (PC800), coke rate, fuel rate and carbon emission rate were decreased by 13.4, 22.1 and 19.25 kg · t−1, respectively. The ratio of ore to coke, solid burden charging rate and hot metal productivity were increased by 4.79%, 7.55 kg · s−1 and 6.38%, respectively. Heat taken away by top gas and energy consumption per ton hot metal were increased by 68.97% and 6.40%, respectively. Generally speaking, hot burden charging was adverse to energy utilization of blast furnace.


      PubDate: 2014-08-16T06:32:32Z
       
  • Role of Mn and P in Texture of Bake Hardening Steel during Heat Treatment
    • Abstract: Publication date: August 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 8
      Author(s): Hua WANG , Hong-lin YANG , Lin LI , Li WANG
      Samples of three ultra-low carbon bake hardening (ULC-BH) steels (BH-0, BH-Mn, and BH-P) were prepared by two annealing processes followed by water quenching and overaging. The texture evolution in the as-treated steels was explored via EBSD and ODE, and the roles of Mn and P elements as well as heat treatment processes in the texture orientation and intensity were investigated. It is found that overaging significantly increases texture intensity of BH-0 and BH-Mn steel, while markedly hinders the texture development in BH-P steel. Based on the microstructure analysis, it can be deduced that the texture variations in BH-0 and BH-Mn steels mainly contribute to carbide (in BH-0 and BH-Mn steels) and manganese containing compound (in BH-Mn steel) or partially to C segregation to dislocation, while the texture variation in BH-P steel is mainly caused by the P and C co-segregation formed during quenching.


      PubDate: 2014-08-16T06:32:32Z
       
  • Corrosion Performance of High Strength 15Cr Martensitic Stainless Steel in
           Severe Environments
    • Abstract: Publication date: August 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 8
      Author(s): Xiang-hong LÜ , Fu-xiang ZHANG , Xiang-tong YANG , Jun-feng XIE , Guo-xian ZHAO , Yan XUE
      High pressure and high temperature corrosion performance of high strength 15Cr martensitic stainless steel was studied in different severe environments—live acid (10% HCl + 1. 5% HF + 3% HAc + 5.1% corrosion inhibitor), spent acid and formation water containing CO2. The results show that the corrosion of high strength 15Cr martensitic stainless steel in live acid is most serious, and the uniform corrosion rate is far greater than those in spent acid and formation water containing CO2 corrosion environments, but all of them can be acceptable for oilfield. Acidizing corrosion inhibitor displays a good matching ability with the high strength 15Cr martensitic stainless steel in terms of decreasing the uniform corrosion rate, which changes mainly the anodic process of high strength 15Cr martensitic stainless steel. The corrosion potential moves to the positive direction, thus the corrosion current density decreases significantly. There arc some different degrees of pitting of high strength 15Cr martensitic stainless steel after corrosion tests in live acid, spent acid and formation water containing CO2, and the pitting density aggravates significantly and the maximum pit depth decreases in the corrosion sequence.


      PubDate: 2014-08-16T06:32:32Z
       
  • Microstructure Evolution and Mechanical Properties of HR3C Steel during
           Long-term Aging at High Temperature
    • Abstract: Publication date: August 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 8
      Author(s): Bin WANG , Zheng-chong LIU , Shi-chang CHENG , Chun-ming LIU , Jing-zhong WANG
      Microstructure evolution and the changes in mechanical properties of HR3C steel during long-term aging at 650, 700 and 750 °C were investigated. The precipitated phases of the aging steel included M23C6 carbides, Z-phase and a trace amount of Nb(C,N). The M23C6 carbides were distributed mainly at the grain boundary, while Z-phase was mainly inside the grains. Amounts of both M23C6 carbides and Z-phase during the aging process increased with increasing aging period and temperature. Coarsening of M23C6 carbides was influenced significantly by aging time and temperature, while the size of the Z-phase was relatively less affected by the aging time and temperature, which had a steady strengthening effect. Coarsening of the M23C6 carbides was the main reason for the decline in high temperature yield strength during long-term aging at 750 °C. The M23C6 carbides were linked into a continuous chain along the grain boundary which accounted for the decrease of toughness during aging.


      PubDate: 2014-08-16T06:32:32Z
       
  • Austenite Grain Refinement and Isothermal Growth Behavior in a Low Carbon
           Vanadium Microalloyed Steel
    • Abstract: Publication date: August 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 8
      Author(s): Geng-wei YANG , Xin-jun SUN , Qi-long YONG , Zhao-dong LI , Xiao-xian LI
      The austenite grain refinement through control of the grain growth during reheating process after thermo-mechanical controlled process (TMCP) in a vanadium microalloyed steel was achieved. The formation of ultra-fine grained austenite was attributed to the high density of austenite nucleation at the ferrite/martensite structure and to the inhibition of austenite growth by (Ti,V)C particles at the relatively low reheating temperature. Corresponding with the precipitation behavior of (Ti,V)C with temperature, the growth behavior of austenite in the vanadium microalloyed steel could be divided into two regions. At lower reheating temperature, austenite grains grew slowly, and ultra-fine grained austenite smaller than 5 μm was successfully obtained. By contrast, the austenite grains grew rapidly at high temperature due to the dissolution of (Ti,V)C particles. According to the measured and predicted results of austenite growth kinetics, two models were developed to describe the growth behavior of austenite grains in two different temperature regions, and the apparent activation energy Q app for grain growth was estimated to be about 115 and 195 kJ/mol, respectively.


      PubDate: 2014-08-16T06:32:32Z
       
  • Microstructure and Mechanical Properties of TWIP Steel Joints
    • Abstract: Publication date: August 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 8
      Author(s): Li-li MA , Ying-hui WEI , Li-feng HOU , Bin YAN
      As a new type of high manganese steel, the twinning induced plasticity (TWIP) steels have attracted a growing interest in the automotive industry due to their good performance. Thin plates of TWIP steel were welded by laser beam welding (LBW) and gas tungsten arc welding (GTAW). The microstructure result shows that GTAW joint has obvious heat-affected zone (HAZ), while the HAZ of LBW joint is almost invisible. The X-ray diffraction result shows that the phase compositions of both joints arc austenitic and no phase transition occurs. Energy dispersive spectrometry result shows that there is violent evaporation of Mn element in LBW joint, while the proportion of Mn element in GTAW joint is almost unchanged. Tensile tests and micro-hardness measurements were performed to take into account the mechanical properties of joints manufactured by the two different processes. The micro-hardness profiles of both joints present a typical saddle distribution, and the hardness of GTAW scam is lower than that of LBW scam. The failure positions of LBW joints arc all located in base metal while the GTAW joints arc all at the weld toe due to the softening of HAZ. By means of scanning electron microscopy, a typical ductile fracture is observed in LBW joint, while a brittle fracture with quasi-cleavage fracture characteristic is observed in GTAW joint.


      PubDate: 2014-08-16T06:32:32Z
       
  • Effect of Boron Mud and CaF2 on Surface Tension and Density of
           CaO-SiO2-B2O3 Ternary Slag Systems
    • Abstract: Publication date: August 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 8
      Author(s): Li-li YANG , Hong-ming WANG , Xiang ZHU , Gui-rong LI
      The effect of boron mud and CaF2, which were used as fluxing agents, on surface tension and density of CaO-SiO2-B2O3 ternary slag systems was investigated. The surface tension and density were measured by using the ring detachment method and Archimedean method, respectively. The results indicated that surface tension and density of the slag systems decreased with increasing temperature in the range of 1380—1480 °C. When 5%—10% CaF2 was employed as fluxing agent, the surface tension and density of slag were decreased with increasing CaF2 content, and the surface tension changed from 0.3 to 0.6 N/m, while the density changed from 3.4 to 4.1 g/cm3. However, when using 5%—10% boron mud as fluxing agent, the surface tension was enhanced, whereas the density decreased with the increase of boron mud content, and the variation range was 0.4—0.6 N/m for surface tension and 3.2—3.9 g/cm3 for the density. As a conclusion, using boron mud as fluxing agent to substitute for CaF2 did not cause significant changes in slag surface tension and density.


      PubDate: 2014-08-16T06:32:32Z
       
  • Effect of Slab Subsurface Microstructure Evolution on Transverse Cracking
           of Microalloyed Steel during Continuous Casting
    • Abstract: Publication date: August 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 8
      Author(s): Yun-feng LI , Guang-hua WEN , Ping TANG , Jian-quan LI , Cheng-li XIANG
      As to the continuous casting process of low carbon microalloyed steel, subsurface microstructure evolution plays an important role in the slab surface cracking. In order to study the effect of the slab subsurface microstructure evolution on the transverse cracking, three different secondary cooling patterns (i.e., mild cooling, strong cooling and controlled cooling) were performed in the corresponding slab curved continuous caster. Based on the metallographic results, three transformation regions were found to be formed with the evolution of microstructures at different depths in the slab subsurface. The three regions arc strong cooling transformation (SCT) region, double phase transformation (DPT) region and mild cooling transformation (MCT) region, respectively. Meanwhile, it was also found that the crack index used for evaluating slab surface cracking susceptibility was decreased when the range of the DPT region was increased. This can be explained by the fact that the double phase transformation (austenite-ferrite-austenite) occurred resulting from thermal cycling in DPT region, which resulted in promoting the refinement of prior austenite grains and inhibiting the precipitation of film-like ferrite and chain-like precipitates. Under the controlled cooling pattern, the widely-distributed DPT region was formed in the range of 3.5—8.0 mm to the slab surface. And compared with other cooling patterns, the cracking susceptibility is lowest with a crack index of 0.4.


      PubDate: 2014-08-16T06:32:32Z
       
  • CO2 Gasification Characteristics of High and Low Reactivity Cokes
    • Abstract: Publication date: August 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 8
      Author(s): Bing GAO , Jian-liang ZHANG , Hai-bin ZUO , Cheng-lin QI , Yan RONG , Zhe WANG
      In order to effectively utilize the high reactivity coke, the gasification characteristics of high and low reactivity cokes were investigated at 1100 °C. Low reactivity coke A and high reactivity coke B were chosen and charged into the reaction tube in two methods. The results indicated that the mass loss ratio of high reactivity coke in mixed cokes was more significant than that of single high reactivity coke in the middle stage of reaction. Nevertheless, the mass loss ratio of low reactivity coke in mixed cokes was less than that of single low reactivity coke. It was mainly attributed to gas diffusion and internal reaction of coke. When high and low reactivity cokes were mixed, the practical average mass loss ratio was nearly the same as the weighted average. The microscopic structures of coke indicated that with the increase of reaction time, the external and internal layers of low reactivity coke reacted more uniformly with CO2, whereas the reaction degree of external layer of high reactivity coke was obviously higher.


      PubDate: 2014-08-16T06:32:32Z
       
 
 
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