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  Subjects -> ENVIRONMENTAL STUDIES (Total: 781 journals)
    - ENVIRONMENTAL STUDIES (717 journals)
    - POLLUTION (21 journals)
    - TOXICOLOGY AND ENVIRONMENTAL SAFETY (35 journals)
    - WASTE MANAGEMENT (8 journals)

ENVIRONMENTAL STUDIES (717 journals)            First | 1 2 3 4 5 6 7 8     

International Archives of Occupational and Environmental Health     Hybrid Journal   (Followers: 4)
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: 2)
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: 9)
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: 6)
International Journal of Environment and Pollution     Hybrid Journal   (Followers: 5)
International Journal of Environment and Sustainable Development     Hybrid Journal   (Followers: 15)
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: 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: 15)
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: 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: 5)
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: 9)
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: 9)
IOP Conference Series: Earth and Environmental Science     Open Access   (Followers: 7)
Iranian Studies     Hybrid Journal   (Followers: 9)
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: 2)
Isotopes in Environmental and Health Studies     Hybrid Journal   (Followers: 1)
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: 9)
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: 5)
Journal of Agrobiology     Open Access   (Followers: 2)
Journal of Applied Ecology     Hybrid Journal   (Followers: 238)
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: 24)
Journal of Biochemical and Molecular Toxicology     Hybrid Journal   (Followers: 4)
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: 2)
Journal of Climate     Full-text available via subscription   (Followers: 25)
Journal of Coastal Research     Full-text available via subscription   (Followers: 10)
Journal of Computational Environmental Sciences     Open Access  

  First | 1 2 3 4 5 6 7 8     

Journal Cover Journal of Iron and Steel Research, International     [SJR: 0.586]   [H-I: 13]
   [9 followers]  Follow    
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   ISSN (Print) 1006-706X
   Published by Elsevier Homepage  [2585 journals]
  • Mechanisms of Swelling of Iron Ore Oxidized Pellets in High Reduction
           Potential Atmosphere
    • Abstract: Publication date: January 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 1
      Author(s): Run-sheng XU , Jian-liang ZHANG , Hai-bin ZUO , Ke-xin JIAO , Zheng-wen HU , Xiang-dong XING
      The influences of the time, temperature and atmosphere on the reduction swelling of oxidized pellets were investigated by single factor experiments. The mechanisms of reduction swelling of oxidized pellets were analyzed and investigated by SEM (scanning electron microscopy) and XRD (X-ray diffractometer) analysis. The results show that the change rules of reduction swelling index of oxidized pellets in different reduction atmospheres are very similar. With the increase of reduction time, the reduction swelling index moves up firstly and then down. When the reduction temperature is above 900 °C, α-quartz turns into α-tridymite, and the transition generates additional volume expansion effect. The reduction swelling index changes faster in H2 atmosphere than in CO atmosphere. Increasing H2 content in the reduction atmosphere is useful to decrease the reduction swelling index, but it is also easy to cause oxidized pellets cracking.


      PubDate: 2015-01-14T20:04:16Z
       
  • A Modified Model for Calculating Theoretical Flame Temperature in Blast
           Furnace and Its Application
    • Abstract: Publication date: January 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 1
      Author(s): Li ZHU , Keng WU , Er-hua ZHANG , Yuan SHE , Wen-long ZHAN , Qi-hang LIU
      The theoretical flame temperature (TFT) before tuyere, always highly concerned by blast furnace (BF) operators, is one of the most important parameters for evaluating the thermal state of hearth. However, some influencing parameters, for example, the SiO2 reduction by carbon, were always neglected or inaccurate when calculating the TFT. According to the definition of TFT, the temperature of coke into raceway and the reduction rate of SiO2 in ash of coke and pulverized coal were obtained by analyzing the samples before tuyere in blast furnace. Taking full account of different factors, a modified model for calculating the TFT in blast furnace was established. The effects of the oxygen enrichment rate, the reduction rate of SiO2 in raceway, the ash content in coke and pulverized coal and the pulverized coal injection (PCI) rate on TFT were determined quantitatively. The modified model was applied to selecting the used coal for PCI in blast furnace. Considering the different SiO2 contents of mixed coal, the calculated TFT remained a stable level. This showed that the selected coal could be suitable for PCI in blast furnace.


      PubDate: 2015-01-14T20:04:16Z
       
  • Effects of Quicklime and Iron Tailings as Modifier on Composition and
           Properties of Steel Slag
    • Abstract: Publication date: January 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 1
      Author(s): Zuo-shun ZHANG , Fang LIAN , Lai-jun MA , Yu-sheng JIANG
      Steel slag had lower activity and much lower hydration rate than cement. Quicklime and iron tailings were designed as modification agent to adjust the composition and properties of high temperature steel slag. The results show that quicklime as modifier can greatly increase the content of cementitious minerals in modified steel slag and also promote the decomposition of RO phases and transformation of MgO in RO phase to f-MgO. After high temperature modification with compound modifier of quicklime and iron tailings, steel slag shows the main mineral phases of C3S, C2F and MgFe2O4. The activity index of modified steel slag at 28 days reaches 95.5% when the steel slag is modified by 15% of the compound modifier with the ratio of quicklime to iron tailings equal to 2:1 at 1350 °C. Moreover, the sample with the modified steel slag exhibits the dense structure of hydration paste and the main hydration products of C-S-H gels and Ca(OH)2 crystals.


      PubDate: 2015-01-14T20:04:16Z
       
  • Experiment and Simulation of Metal Flow in Multi-stage Forming Process of
           Railway Wheel
    • Abstract: Publication date: January 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 1
      Author(s): Xiao-hui SHEN , Wei CHEN , Jun YAN , Lei ZHANG , Jing ZHANG
      To investigate the metal flow during the railway wheel forming process, experiments and finite element method (FEM) simulation were carried out. An axisymmetric modeling for the wheel rolling process was proposed to predict the metal flow in radial direction, by which the whole multi-stage forming process could be simulated in axisymmetric and integral way. The result shows that the axisymmetric simulation method was an effective method to explore the metal flow in radial direction and to analyze the relationships of tools motion during the wheel rolling. The detail information about metal flow in railway wheel forming process was obtained. The metal in the wheel web was from the area near the half radius of the original billet; the chill zone of the billet became an envelope of the rim and part of the web with a maximum thickness of about 6 mm below the tread. At the wheel rolling stage, the metal in the rim flowed towards the web; the metal near the surfaces of the conjunction region between the web and rim suffered severe shear deformation.


      PubDate: 2015-01-14T20:04:16Z
       
  • Effects of Steel Teeming in New Slide Gate System with Electromagnetic
           Induction
    • Abstract: Publication date: January 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 1
      Author(s): Qiang WANG , De-jun LI , Xing-an LIU , Xue-bin WANG , Jie DONG , Ji-cheng HE
      Steel teeming time is a very important parameter in the new slide gate system with electromagnetic induction (called electromagnetic steel teeming system), and how to shorten this time is a key to realize application of the new system in continuous casting. The effects of power parameters, coil position, nozzle material and other factors on the steel teeming time were investigated by a self-designed electromagnetic steel teeming system in detail. The experimental results show that the relationship between power and steel teeming time is nonlinear. The coil position has great influence on steel teeming time. And the upper nozzle with high permeability can reduce the teeming time. In addition, the steel teeming time becomes minimum when the size of the spherical cast iron particles is 2.0 mm. This research can provide technical references for the industrial application of the new electromagnetic steel teeming system.


      PubDate: 2015-01-14T20:04:16Z
       
  • Definition of Raceway Boundary Using Fractal Theory
    • Abstract: Publication date: January 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 1
      Author(s): Jun-jie SUN , Zhi-guo LUO , Zhan-xia DI , Tao ZHANG , Heng ZHOU , Zong-shu ZOU
      The particle velocity contours were obtained by tracking the tracer particles in the raceway region of the COREX melter gasifier model and the contours were irregular. According to the fractal theory, the fractal dimensions of different particle velocity contours were determined. Through the analysis of the fractal dimensions, a new method for precise determination of the raceway boundary was proposed. The results show that, when the velocity is less than 0.18 m/s, the particles are located in the stagnant zone and the fractal dimensions of particle velocity contours are almost constant as 1.41; when the velocity increases from 0.18 to 0.83 m/s, the particles are located in the rapid movement zone and the fractal dimensions decrease gradually from 1.41 to 1.05; when the velocity is greater than 0.83 m/s, the particles are located in the cavity zone and the fractal dimensions are again almost constant as approaching to 1.00. Therefore, the velocity contour of 0.18 m/s, which is critical to distinguish the rapid movement zone and stagnant zone, can be used to define the raceway boundary. Based on this method, the effect of blowing rate on raceway size was calculated and the results show that the penetration depth and height of the raceway increase with the increase of blowing rate.


      PubDate: 2015-01-14T20:04:16Z
       
  • Influences of Austenization Temperature and Annealing Time on Duplex
           Ultrafine Microstructure and Mechanical Properties of Medium Mn Steel
    • Abstract: Publication date: January 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 1
      Author(s): Chang WANG , Wen-quan CAO , Yun HAN , Cun-yu WANG , Chong-xiang HUANG , Han DONG
      A duplex ultrafine microstructure in a medium manganese steel (0.2C-5 Mn) was produced by austenite reverted transformation annealing (ART-annealing). The microstructural evolution during annealing was examined by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). Based on the microstructure examination, it was found that some M3C type carbides appeared in the martensitic matrix at the beginning of the ART-annealing. But with further increasing annealing time, these carbides would be dissolved and finally disappeared. Meanwhile, the austenite lath was developed in the ART-annealing process and the volume fraction of austenite increased with the increase of the annealing time, which resulted in a duplex microstructure consisting of ultrafine-grained ferrite and large fraction of reverted austenite after long time annealing. The mechanical property examinations by uniaxial tensile tests showed that ART-annealing (6 h, 650 °C) resulted in a superhigh product of strength to elongation up to 42 GPa • %.


      PubDate: 2015-01-14T20:04:16Z
       
  • Response Characteristics and Adiabatic Heating during High Strain Rate for
           TRIP Steel and DP Steel
    • Abstract: Publication date: January 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 1
      Author(s): Yi GAO , Chao XU , Zhong-ping HE , Yan-lin HE , Lin LI
      By using a static and high-speed material testing machine, tensile deformation behaviors of two kinds of Si-Mn TRIP (transformation induced plasticity) steels and DP (dual phase) steel were studied in a large range of strain rates (0.001 – 2000 s−1). Temperature variation during adiabatic heating and the amount of retained austenite at fracture were measured by an infrared thermometer and an X-ray stress analyser, respectively. The microstructure of steels was observed by optical microscopy (OM) and scanning electron microscopy (SEM) before and after tensile test. It was found from the experimental results that the tensile strength of these steels increased, and the fracture elongation firstly decreased and subsequently increased, as the strain rate increased in the range of 0.1 – 2000 s−1. The temperature raised during adiabatic heating of TRIP steel was in the range of 100 – 300 °C, while that of the DP steel was in the range of 100 – 220 °C. The temperature rise of these steels increased with increasing the strain rate, as well as the amount of the transformed retained austenite in TRIP steels. It was confirmed that austenite to martensite transformation is not suppressed by adiabatic heating.


      PubDate: 2015-01-14T20:04:16Z
       
  • Microstructure Evolution and Microhardness of Ultrafine-grained High
           Carbon Steel during Multiple Laser Shock Processing
    • Abstract: Publication date: January 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 1
      Author(s): Yi XIONG , Tian-tian HE , Feng-zhang REN , Peng-yan LI , Lu-fei CHEN , Alex A. VOLINSKY
      Surface microstructure and microhardness of (ferrite + cementite) microduplex structure of the ultrafine-grained high carbon steel after laser shock processing (LSP) with different impact times were investigated by means of scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and microhardness measurements. Equiaxed ferrite grains were refined from 400 to 150 nm, and the cementite lamellae were fully spheroidized, with a decrease of the particle diameter from 150 to 100 nm as the impact times increased. The cementite dissolution was enhanced significantly. Correspondingly, the lattice parameter of α-Fe and microhardness increased with the impact times.


      PubDate: 2015-01-14T20:04:16Z
       
  • Influence of Plastic Deformation on Thermal Stability of Low Carbon
           Bainitic Steel
    • Abstract: Publication date: January 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 1
      Author(s): Chao SUN , Shan-wu YANG , Rui ZHANG , Xian WANG , Hui GUO
      Bainite is metastable due to its high dislocation density, and consequently bainitic steel structures have the problem of thermal stability. Plastic deformation of bainite can further increase dislocation density and change dislocation configuration at the same time. The influence of plastic deformation on thermal stability of low carbon bainitic steel during isothermal holding at 650 °C was investigated with hardness analysis, in-situ tracing metallographic analysis and transmission electron microscopy. Bainite in the low carbon steel evolves into polygonal ferrite via recovery and recrystallization during isothermal holding at 650 °C. There is a considerably long period (about 20 h) between end of recovery and commencement of recrystallization of undeformed bainite, in which the hardness of the sample maintains a constant value slightly lower than that before reheating. Slight plastic deformation of bainite induces rearrangement of pre-existing dislocations and forming of low-energy dislocation cells inside bainite laths, which has little influence on thermal stability of bainite, whereas heavy plastic deformation results in obvious dislocation multiplication and accelerates recrystallization of bainite. Recrystallization of heavily-deformed bainite occurs preferentially at prior austenite grains boundaries. The samples subjected to heavy torsion exhibit obviously higher thermal stability than the samples subjected to heavy compression despite their same initial hardness, which can be attributed to different influences of torsion and compression on dislocations and boundaries of bainite.


      PubDate: 2015-01-14T20:04:16Z
       
  • Magnetic Properties of Nanocrystalline Powder Cores Fabricated by
           Mechanically Crushed Powders
    • Abstract: Publication date: January 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 1
      Author(s): Chun-bo HUANG , Tian-cheng LIU , Xiang-yue WANG , Cao-wei LU , De-ren LI , Zhi-chao LU
      Fe73.5Cu1Nb3Si15.5B7 nanocrystalline powder cores with different particle sizes ranging from 10 to 125 μm were fabricated by cold-pressing techniques. The cores exhibited increased core loss P cv and decreased initial permeability μi with addition of fine powders below 50 μm in size, and the content should be less than 40 mass%. It was thought to be closely related to the high coercive force H c due to the stresses generated during the crushing process and high demagnetization fields of small powders. Furthermore, modifying the alloy compositions by adding defined amount of Ni could improve the soft magnetic properties, including superior characteristics of permeability under high direct current (DC) bias field and comparable low core loss at high frequency.


      PubDate: 2015-01-14T20:04:16Z
       
  • Nickel Release Rate of Several Nickel-containing Stainless Steels for
           Jewelries
    • Abstract: Publication date: January 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 1
      Author(s): Jun-ping YUAN , Wei LI , Chang WANG , Chun-yu MA , Ling-xia CHEN , De-dong CHEN
      Nickel-containing stainless steels have been widely applied in watch and jewelry production, and their responses to the Nickel Directive become a universal concern in the industry. The nickel release rates and corrosion behaviors of types 316L, 304, 303 and 201 stainless steels under the conditions of solid solution and mirror polishing were studied by artificial sweat soaking and electrochemical methods. The results show that the weekly nickel release rates in artificial sweat do not strictly correspond to the nickel contents, which present a descending order as 303 stainless steel of 2. 06 μg/cm2, 201 stainless steel of 1. 51 μg/cm2 304 stainless steel of 0. 08 μg/cm2 and 316L stainless steel of 0. 02 μg/cm2. Both the nickel release rates of type 303 and 201 stainless steels significantly exceed the threshold values regulated in EN1811: 2011; therefore, they should be avoided to be used as watch and jewelry materials owing to the risk of nickel sensitization. The nickel release rates of 316L and 304 stainless steels meet the requirements of the standard. Sulfide inclusions in stainless steel become the sources of pitting and exacerbate the damage of the passivation membrane, which is the significant cause to enhance the nickel release rates.


      PubDate: 2015-01-14T20:04:16Z
       
  • Effects of Carbon Content on Mechanical Properties of Inconel 718 Alloy
    • Abstract: Publication date: January 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 1
      Author(s): Wen-jie ZHENG , Xian-ping WEI , Zhi-gang SONG , Qi-long YONG , Han FENG , Qing-cheng XIE
      For improving the service performance of Inconel 718 alloy, especially used as a corrosion-resistant alloy for special environment, the microstructure and mechanical property of different carbon-containing Inconel 718 alloys were investigated by the Thermo-Calc software and experiments. The experimental results indicated that the morphology, distribution and types of carbides mainly existing in the form of MC were hardly influenced by solution treatment at 1050 °C for 1 h. The precipitation amount and particle size of carbides decreased with the decrease of carbon content, which was the main reason resulting in the increase of ductility and toughness. In addition, moving dislocation could be restrained by the precipitation of carbides. Therefore, the strength could benefit from the precipitation strengthening of carbides when the precipitation of γ′/γ″ phase was not influenced by the precipitation of carbides.


      PubDate: 2015-01-14T20:04:16Z
       
  • Abrasive Wear Behavior and Mechanism of High Chromium Cast Iron
    • Abstract: Publication date: January 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 1
      Author(s): Ting SUN , Ren-bo SONG , Xu WANG , Peng DENG , Chun-jing WU
      The abrasive wear behavior of high chromium cast iron (containing 12. 9 mass% chromium) austenitized at 1050 °C for 2 h and austempered in salt bath at 320 °C for 4 h was evaluated. Abrasive wear was performed using alumina abrasive under four different loads, namely 50, 100, 150, and 200 N, for 36000 cycles. The worn surfaces and wear debris were analyzed by scanning electron microscopy, laser confocal microscopy and X-ray diffraction. Micro-hardness profiles were also obtained in order to analyze the strain-hardening effects beneath the contact surfaces. Results indicate that the retained austenite in high chromium cast iron has experienced induced martensitic transformation after tests, for small amounts of retained austenite could be detected by X-ray diffraction. In addition, there is a close relationship between wear mechanism and test load. Under the condition of lower test load, the wear mechanism is an uninterrupted and repeated process, during which matrix is cut at first and then fine carbides flake off. As to higher test load, scratching and spalling induced by cleavage fracture of blocky carbide are the wear mechanism.


      PubDate: 2015-01-14T20:04:16Z
       
  • Precipitation Strengthening by Nanometer-sized Carbides in Hot-rolled
           Ferritic Steels
    • Abstract: Publication date: December 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 12
      Author(s): Xiao-pei WANG , Ai-min ZHAO , Zheng-zhi ZHAO , Yao HUANG , Zhi-da GENG , Yang YU
      The mechanical properties of the hot-rolled plates of Ti steel and Ti-Mo steel after isothermal transformation in a temperature range of 600–700 °C for 60 min have been tested, and the microstructures of the matrix and the characteristics of precipitated nanometer-sized carbides have also been examined by scanning electron microscopy and transmission electron microscopy. The precipitation regularity of nanometer-sized carbides has been studied by thermodynamic method and the contributions of corresponding strengthening mechanisms to the total yield strength have been calculated. The tensile strength of hot-rolled Ti-Mo ferritic steel can achieve 780 MPa with an elongation of 20.0% after being isothermally treated at 600 °C for 60 min, and the tensile strength of Ti steel is 605 MPa with an elongation of 22.7%, according to the results of tensile tests. The critical nucleation size of (Ti, Mo)C is smaller than that of TiC at a given isothermal temperature, but the nucleation rate of (Ti, Mo.)C is larger than that of TiC. The grain-refinement strengthening and precipitation strengthening contribute the main amount of the total yield strength. The major increase in yield strength with the decrease of isothermal temperature results from the contribution of precipitation strengthening. The contribution of precipitation strengthening to the yield strength of the steels has been estimated. The ferrite phase can be strengthened by about 400 MPa through precipitation strengthening in Ti-Mo steel isothermally treated at 600 °C for 60 min, which is about 200 MPa higher than that of Ti steel under the same conditions.


      PubDate: 2014-12-11T18:14:13Z
       
  • Vortex Flow Pattern in a Slab Continuous Casting Mold with Argon Gas
           Injection
    • Abstract: Publication date: December 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 12
      Author(s): Zhong-qiu LIU , Feng-sheng QI , Bao-kuan LI , Mao-fa JIANG
      An Eulerian-Eulerian two-fluid model was developed to study the vortex flow inside a slab continuous casting mold with argon gas injection. Interfacial momentum transfer that accommodated various interfacial forces including drag force, lift force, virtual mass force, and turbulent dispersion force was considered. Predicted results agree well with experimental measurements of the water model in two-phase flow pattern and vortex flow structures. Three typical flow patterns with different argon steel ratios (ASRs) have been obtained: “double roll”, “three roll”, and “single roll”. The flow pattern inside the mold alternates among the three types or it may attain some intermediate condition. With increasing ASR, the positions of vortices move from the submerged entry nozzle to the narrow face of the mold, and the sizes of vortices are reduced gradually. The rotating directions of vortices are all from high velocity area to low velocity area. Two mechanisms of vortex formation on the top surface have been suggested, i. e., congruous shear flow and incongruous shear flow.


      PubDate: 2014-12-11T18:14:13Z
       
  • Non-equilibrium Grain-boundary Segregation of Phosphorus in an Fe-17Cr
           Alloy
    • Abstract: Publication date: December 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 12
      Author(s): Kai WANG , Hong SI
      In order to confirm the segregation characteristic of phosphorus in an Fe-17Cr alloy at grain boundary, the phosphorus segregation was obtained by Auger electron spectroscopy. The results show that a maximum phosphorus segregation appeared at 450 °C for all specimens aged for 30 min at 350, 400, 450, 500, and 600 °C after being solution-treated at 1000 °C for 1 h. These results were analyzed by the characteristics of segregation peak temperature of non-equilibrium segregation.


      PubDate: 2014-12-11T18:14:13Z
       
  • Effects of Hot Bending Parameters on Microstructure and Mechanical
           Properties of Weld Metal for X80 Hot Bends
    • Abstract: Publication date: December 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 12
      Author(s): Xu WANG , Bo LIAO , Da-yong WU , Xiu-lin HAN , Yuan-sheng ZHANG , Fu-ren XIAO
      Mechanical properties of weld metal are the key factors affecting the quality of heavy-wall X80 hot induction bends. The effects of bending parameters on the mechanical properties of weld metal for hot bends were investigated by simulation conducted on a Gleeble-3500 thermal simulator. Continuous cooling transformation (CCT) diagrams of the weld metal were also constructed. The influences of hot bending parameters (such as reheating temperature, cooling rate, and tempering temperature) on the microstructure and mechanical properties of weld metal were also analyzed. Results show that the strength of all weld metal specimens is higher than the value indicated in the technical specification and increases with the increase of reheating temperature, cooling rate, and tempering temperature. The impact toughness is apparently related to the variation of reheating temperature, cooling rate, and tempering temperature.


      PubDate: 2014-12-11T18:14:13Z
       
  • Factors Influencing Dual Phase Steel Flanging Limit Punching
    • Abstract: Publication date: December 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 12
      Author(s): Jian-qing QIAN , Yuan YUE
      Based on pre-punching to hot rolled martensitic and bainitic dual phase steels with similar elongation and work hardening index (n), as well as similar thickness and hole expansion test using taper die, analysis of the hole expansion rate indicated significant difference in their flanging performance. The results indicated that mechanical property was not the only major factor that influenced flanging. Further analysis of the hole border microstructure, work hardening condition, and fracture property showed that the fracture property of sheets was the major factor that influenced flanging performance.


      PubDate: 2014-12-11T18:14:13Z
       
  • Effect of Magnesium on Evolution of Oxide and Sulphide in Liquid Iron at
           1873 K
    • Abstract: Publication date: December 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 12
      Author(s): Tong-sheng ZHANG , De-yong WANG , Mao-fa JIANG
      To reveal the effects of magnesium on the evolution of oxide and sulphide inclusions in liquid iron, both thermodynamic calculations and deoxidization experiments were carried out. The samples extracted from the liquid iron were polished and analyzed by optical microscopy and scanning electron microscopy. The results showed that magnesium could modify oxide and sulphide inclusions simultaneously. Spherical MgO and irregular spinel inclusions were observed in the samples. The elongated MnS inclusions were replaced by small MgO • MgS or MgO • MgS • MnS complex inclusions, and the sulphides were distributed dispersively. The evolution mechanisms of inclusions were discussed comprehensively, and a proposed model for the formation of oxysulphide was set up.


      PubDate: 2014-12-11T18:14:13Z
       
  • Flow Stress Behaviors and Microstructure Evolution of 300M High Strength
           Steel under Isothermal Compression
    • Abstract: Publication date: December 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 12
      Author(s): Rong-sheng QI , Bao-feng GUO , Xin-gang LIU , Miao JIN
      The compressive deformation behaviors of 300M high strength steel were investigated over a wide range of temperatures (850–1200 °C) and strain rates (0.001–10s−1) on a Gleeble-3800 thermo-mechanical simulator. The measured flow stress was modified by the corrections of the friction and the temperature compensations, which nicely reflect negative effects of the friction and temperature on the flow stress. The corrected stress-strain curves were the dynamic recrystallization type on the conditions of higher deformation temperature and lower strain rate. Flow stress increases with the increase of strain rate at the same deformation temperature and strain. By contrast, flow stress decreases with the increase of temperature at the same strain rate and strain. Dependence of the peak stress on temperature and strain rate for 300M steel is described by means of the conventional hyperbolic sine equation. By regression analysis, the activation energy (Q) in the whole range of deformation temperature is determined to be 367.562 kJ/mol. The effects of the temperature and the strain rate on microstructural evolution are obvious. With the increase of the deformation temperature and the decrease of the strain rate, the original austenite grain sizes of 300M steel increase. At the same time, the corrected flow stress curves more accurately determine the evolution of the microstructure.


      PubDate: 2014-12-11T18:14:13Z
       
  • Effect of Strengthening Phase on Deformation Behaviour during Uniaxial
           Tension of Hot-rolled Dual Phase Steel
    • Abstract: Publication date: December 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 12
      Author(s): Le-yu ZHOU , Bo JIANG , Tian-hao CUI , Dan ZHANG , Jian-zhong HE , Ya-zheng LIU
      Two kinds of C-Si-Mn-Cr series tested steels were designed to obtain dual phase microstructures of ferrite (F) + martensite (M) or ferrite (F) + bainite (B) with different mechanical properties. Effects of strengthening phase on yielding and fracture behaviours during uniaxial tension of dual phase steel were discussed. Compared with hot-rolled martensite dual phase steel, ferrite-bainite dual phase steel has high ratio of yield strength to tensile strength (YS/TS) and low elongation. During necking process of uniaxial tension, microvoids of ferrite-martensite steel are generated by fracture of ferrite/martensite boundary or martensite islands with irregular shape. But ferrite matrix elongated remarkably along deformation direction, and strengthening phase also coordinated with ferrite matrix. Compatible deformation between ferrite and bainite is distinct. Ferrite-bainite dual phase steel has fine and less microvoid, and phase boundary of ferrite and bainite is beneficial for restraining generation and extending of microvoid.


      PubDate: 2014-12-11T18:14:13Z
       
  • 3D Thermo-mechanical Coupled Simulation of Whole Rolling Process for 60
           kg/m Heavy Rail
    • Abstract: Publication date: December 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 12
      Author(s): Nuan-nuan PEI , Guo-ming ZHU , Bo LI , Gong-ming TAO , Yong-lin KANG
      3D thermo-mechanical coupled simulation of whole rolling process for 60 kg/m heavy rail was accomplished by FEM method. The finite element model, physical parameters of U75V and parameter setting of simulation were introduced in detail. The whole rolling process of 60 kg/m heavy rail was divided into 27 time cells to simulate respectively, and the model rebuilding and temperature inheritance method in intermediate pass were proceeded. Then, based on simulation results, the workpiece deformation result, metal flow, stress and strain of 60 kg/m heavy rail for typical passes were obtained. The temperature variation curves of whole rolling process for section key points of 60 kg/m heavy rail were plotted, and the temperature falling law of whole rolling process for 60 kg/m heavy rail was studied. In addition, temperature distribution of 60 kg/m heavy rail after whole rolling process was analyzed, and the results showed that temperature was highest at center of rail head and lowest at fringe of rail base. Moreover, the simulation results and measured results of rolling force for 60 kg/m heavy rail were compared, and the regularity was in good agreement.


      PubDate: 2014-12-11T18:14:13Z
       
  • Effect of Electromagnetic Stirring on Molten Steel Flow and Solidification
           in Bloom Mold
    • Abstract: Publication date: December 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 12
      Author(s): Zhen-guo YANG , Bao WANG , Xiao-feng ZHANG , Ya-tao WANG , Hong-biao DONG , Qing LIU
      The effect of electromagnetic stirring on molten steel flow and heat transfer in a 260 mm×300 mm bloom mold was investigated by using a method combining both finite element method and finite volume method. The simulation results related to magnetic fields were consistent with the onsite measured data. The magnetic flux density increased with increasing the current intensity but decreased with increasing the current frequency. Electromagnetic stirring caused molten steel to flow with rotation on a horizontal section and two sets of recirculation regions with opposite reflow directions in a longitudinal section formed. The maximum tangential velocity increased with increasing the current intensity and frequency. Furthermore, the superheat degree of the molten steel on the outlet cross section of the mold decreased with increasing the current intensity. Electromagnetic stirring caused the emergence of a zero growth zone of solidified shell in the effective stirring zone. For the 260 mm × 300 mm bloom continuous caster of bearing steel, the appropriate values of current intensity and current frequency of electromagnetic stirring were found to be 300 A and 3 Hz, respectively.


      PubDate: 2014-12-11T18:14:13Z
       
  • Mass Loss and Direct Reduction Characteristics of Iron Ore-coal Composite
           Pellets
    • Abstract: Publication date: December 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 12
      Author(s): Yi MAN , Jun-xiao FENG , Yan-mei CHEN , Jing-zhi ZHOU
      Mass loss and direct reduction characteristics of iron ore-coal composite pellets under different technological parameters were investigated. Meanwhile, changes of iron phase at different temperatures were analyzed by using X-ray diffraction (XRD), and characteristics of crushed products were studied by using a scanning electron microscope (SEM). The results showed that heating rate had little influence on the reduction, but the temperature played an important role in the reduction process. The mass loss rate increased rapidly from 800 to 1100 °C. The reduction process can be divided into three steps which correspond to different temperature ranges. Fe2 O3 began to transform into Fe3O4 below 500 °C, and FeO was reduced into Fe from 900 °C. At 900 °C, the reduction product showed a clear porous structure, which promoted the reduction progress. At 1000 °C, the metallic Fe dominated the sample, and the reduction reached a very high degree.


      PubDate: 2014-12-11T18:14:13Z
       
  • Growth Rate, Microstructure and Phase Composition of Oxide Scales for
           Three Typical Steels in Simulated Continuous Casting Process
    • Abstract: Publication date: December 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 12
      Author(s): Nan WANG , Jian-hong DONG , Wei-jun HUANG , Bo LI , Min CHEN
      Growth rate, microstructure and phase composition of scale layer formed during oxidation in 56% H2O-9%O2-N2 and following continuous cooling in ambient air were experimentally investigated by means of optical microscopy, scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS) and X-ray diffraction (XRD) for 45, 20CrMnTi and TTS443M steels respectively, to examine the effects of strand surface temperature and steel composition on the scale formation in simulated continuous casting process. The growth rates were found to be approximately parabolic and the calculated activation energy of TTS443M steel is much higher than those of the two other steels. For 45 and 20CrMnTi steels, the scale layers were looser and a distinct gap formed at the scalc-sub-strate interface at higher strand surface temperature. The dominant phases within the scale were iron oxides except for FeO • Cr2 O3 phase simultaneously existing in the oxide scale of 20CrMnTi steel. On the other hand, the scale layer formed on TTS443M steel was compact and tightly attached to the steel surface. At both lower and higher strand surface temperature, iron oxide was main phase in external layer of the scale, while chromia was dominant in inner layer with an appreciable Cr enrichment.


      PubDate: 2014-12-11T18:14:13Z
       
  • Microstructure and Properties of an Advanced Nickel-base PM Superalloy
    • Abstract: Publication date: December 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 12
      Author(s): Chao-jie WU , Yu TAO , Jian JIA
      The need for nickel-base powder metallurgy (PM) superalloy turbine discs is becoming increasingly evident. With the eventual aim of improving thrust-to-weight ratio of aeroengines for power generation, well integration of significantly high strength, high damage tolerance and high-temperature capability would be reasonably required. An advanced PM superalloy, which was designed for applications up to 815–850 °C, was experimentally investigated. Emphasis was primarily put on microstructure and mechanical properties. The results indicated the measured phases in the sample were composed of γ, γ′ MC, and M3 B2. With uniform coarse grain microstructure (ASTM 5–6), the sample appeared to exhibit overwhelming superiority over the prior art materials FGH95, FGH96, FGH97 and FGH98. The dominant embodiments consisted of high tensile strength (R m = 1000 MPa and R p0.2 = 800 MPa at 850 °C), strong creep resistance (ξ = 0.12% at 8150 °C /400 MPa/50 h), and considerable stress-rupture life (τ = 457.4 h at 815 °C/450 MPa). The technical practicability of applications up) to 815–850 °C of this alloy was conclusively proved.


      PubDate: 2014-12-11T18:14:13Z
       
  • Metallurgical Studies of Austenitic Stainless Steel 304 under Warm Deep
           Drawing
    • Abstract: Publication date: December 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 12
      Author(s): Jayahari Lade , Balu Naik Banoth , Amit Kumar Gupta , Swadesh Kumar Singh
      Austenitic stainless steel 304 was deep drawn with different blank diameters under warm conditions using 20 t hydraulic press. A number of deep drawing experiments both at room temperature and at 150 °C were conducted to study the metallography. Also, tensile test experiments were conducted on a universal testing machine up to 700 °C and the broken specimens were used to study the fractography of the material using scanning electron microscopy in various regions. The microstructure changes were observed at limiting draw ratio (LDR) when the cup is drawn at different temperatures. In austenitic stainless steel, martensite formation takes place that is not only affected by temperature, but also influenced by the rate at which the material is deformed. In austenitic stainless steel 304, dynamic strain regime appears above 300 °C and it decreases the formability of material due to brittle fracture as studied in its fractography. From the metallographic studies, the maximum LDR of the material is observed at 150 °C before dynamic strain regime. It is also observed that at 150 °C, grains are coarse in the drawn cups at LDR.


      PubDate: 2014-12-11T18:14:13Z
       
  • 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
       
  • 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
       
  • 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
       
  • 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
       
 
 
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