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  Subjects -> ENVIRONMENTAL STUDIES (Total: 755 journals)
    - ENVIRONMENTAL STUDIES (681 journals)
    - POLLUTION (22 journals)
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ENVIRONMENTAL STUDIES (681 journals)            First | 1 2 3 4     

Showing 601 - 378 of 378 Journals sorted alphabetically
Sciences Eaux & Territoires : la Revue du Cemagref     Open Access  
Scientific Journal of Environmental Sciences     Open Access   (Followers: 1)
Sepsis     Hybrid Journal  
Smart Grid and Renewable Energy     Open Access   (Followers: 8)
Social and Environmental Accountability Journal     Hybrid Journal   (Followers: 2)
Soil and Sediment Contamination: An International Journal     Hybrid Journal   (Followers: 3)
Soil and Tillage Research     Hybrid Journal   (Followers: 6)
SourceOCDE Environnement et developpement durable     Full-text available via subscription   (Followers: 1)
SourceOECD Environment & Sustainable Development     Full-text available via subscription  
South Pacific Journal of Natural and Applied Sciences     Hybrid Journal  
Southern Forests : a Journal of Forest Science     Hybrid Journal   (Followers: 6)
Stochastic Environmental Research and Risk Assessment     Hybrid Journal   (Followers: 4)
Strategic Behavior and the Environment     Full-text available via subscription  
Strategic Planning for Energy and the Environment     Hybrid Journal   (Followers: 4)
Studies in Conservation     Hybrid Journal   (Followers: 11)
Studies in Environmental Science     Full-text available via subscription   (Followers: 6)
Sustainability     Open Access   (Followers: 18)
Sustainability in Environment     Open Access  
Sustainability of Water Quality and Ecology     Hybrid Journal   (Followers: 2)
Sustainable Cities and Society     Hybrid Journal   (Followers: 25)
Sustainable Development     Hybrid Journal   (Followers: 16)
Sustainable Development Law & Policy     Open Access   (Followers: 6)
Sustainable Development Strategy and Practise     Open Access  
Sustainable Environment Research     Open Access  
Sustainable Technologies, Systems & Policies     Open Access   (Followers: 9)
Sustentabilidade em Debate     Open Access  
TECHNE - Journal of Technology for Architecture and Environment     Open Access   (Followers: 5)
Tecnogestión     Open Access  
Territorio della Ricerca su Insediamenti e Ambiente. Rivista internazionale di cultura urbanistica     Open Access  
The Historic Environment : Policy & Practice     Hybrid Journal   (Followers: 4)
The International Journal on Media Management     Hybrid Journal   (Followers: 4)
Theoretical Ecology     Hybrid Journal   (Followers: 9)
Theoretical Ecology Series     Full-text available via subscription   (Followers: 1)
Toxicologic Pathology     Hybrid Journal   (Followers: 16)
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Toxicology     Hybrid Journal   (Followers: 16)
Toxicology and Applied Pharmacology     Hybrid Journal   (Followers: 17)
Toxicology and Industrial Health     Hybrid Journal   (Followers: 7)
Toxicology in Vitro     Hybrid Journal   (Followers: 12)
Toxicology Letters     Hybrid Journal   (Followers: 12)
Toxicology Mechanisms and Methods     Hybrid Journal   (Followers: 10)
Toxicon     Hybrid Journal   (Followers: 3)
Toxin Reviews     Hybrid Journal   (Followers: 1)
Trace Metals and other Contaminants in the Environment     Full-text available via subscription   (Followers: 2)
Trace Metals in the Environment     Full-text available via subscription   (Followers: 2)
Transportation Research Part D: Transport and Environment     Hybrid Journal   (Followers: 27)
Transylvanian Review of Systematical and Ecological Research     Open Access  
Trends in Ecology & Evolution     Full-text available via subscription   (Followers: 157)
Trends in Environmental Analytical Chemistry     Hybrid Journal   (Followers: 2)
Trends in Pharmacological Sciences     Full-text available via subscription   (Followers: 25)
Turkish Journal of Engineering and Environmental Sciences     Open Access   (Followers: 1)
UCLA Journal of Environmental Law and Policy     Open Access   (Followers: 5)
UD y la Geomática     Open Access  
Universidad y Ciencia     Open Access   (Followers: 1)
Urban Studies     Hybrid Journal   (Followers: 48)
Veredas do Direito : Direito Ambiental e Desenvolvimento Sustentável     Open Access  
VertigO - la revue électronique en sciences de l’environnement     Open Access   (Followers: 3)
Villanova Environmental Law Journal     Open Access  
Waste Management & Research     Hybrid Journal   (Followers: 10)
Water Environment Research     Full-text available via subscription   (Followers: 37)
Water International     Hybrid Journal   (Followers: 12)
Water, Air, & Soil Pollution     Hybrid Journal   (Followers: 22)
Water, Air, & Soil Pollution : Focus     Hybrid Journal   (Followers: 9)
Waterlines     Full-text available via subscription   (Followers: 2)
Weather and Forecasting     Full-text available via subscription   (Followers: 15)
Weather, Climate, and Society     Full-text available via subscription   (Followers: 9)
Web Ecology     Open Access   (Followers: 6)
Wetlands     Hybrid Journal   (Followers: 24)
Wilderness & Environmental Medicine     Hybrid Journal   (Followers: 2)
Wildlife Australia     Full-text available via subscription   (Followers: 2)
Wiley Interdisciplinary Reviews - Climate Change     Hybrid Journal   (Followers: 17)
Wiley Interdisciplinary Reviews : Energy and Environment     Hybrid Journal   (Followers: 4)
William & Mary Environmental Law and Policy Review     Open Access   (Followers: 2)
World Environment     Open Access   (Followers: 1)
World Journal of Entrepreneurship, Management and Sustainable Development     Hybrid Journal   (Followers: 4)
World Journal of Environmental Engineering     Open Access   (Followers: 2)
World Journal of Environmental Research     Open Access   (Followers: 1)
Worldviews: Global Religions, Culture, and Ecology     Hybrid Journal   (Followers: 8)
Zoology and Ecology     Hybrid Journal   (Followers: 4)
气候与环境研究     Full-text available via subscription   (Followers: 1)

  First | 1 2 3 4     

Journal Cover Journal of Iron and Steel Research, International
  [SJR: 0.784]   [H-I: 16]   [6 followers]  Follow
    
   Full-text available via subscription Subscription journal
   ISSN (Print) 1006-706X
   Published by Elsevier Homepage  [2969 journals]
  • Evaluation of Burden Descent Model for Burden Distribution in Blast
           Furnace
    • Abstract: Publication date: August 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 8
      Author(s): Ping ZHOU, Peng-yu SHI, Yan-po SONG, Kai-le TANG, Dong FU, Chenn Q. ZHOU
      Mathematical models for burden descending process have been applied to obtain whole burden structures in blast furnace, whereas the accuracy of those burden descent models has not been sufficiently investigated. Special evaluation method based on timeline burden profiles was established to quantitatively evaluate the error between experimental and modeled burden structures. Four existing burden descent models were utilized to describe the burden structure of a 1/20 sealed warm blast furnace. Input modeling conditions including initial burden profile, descending volumes in each time interval, and normalized descending velocity distribution were determined via special image processing technology. Modeled burden structures were evaluated combined with the published experimental data. It is found that all the models caught the main profile of the burden structure. Furthermore, the improved nonuniform descent model (Model IV) shows the highest level of precision especially when burden descends with unstable velocity distribution tendency. Meanwhile, the traditional nonuniform descent model (Model III) may also be desirable to model the burden descending process when the burden descending velocity presents a linear tendency. Finally, the uniform descent model (Model I) might be the first option for roughly predicting burden structure.


      PubDate: 2016-08-18T15:16:54Z
       
  • Wear Mechanism of Iron-based Alloy Coating by Arc Spraying
    • Abstract: Publication date: August 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 8
      Author(s): Zeng-rong LI, De-yuan LI, Nan-nan ZHANG, He HUANG, Xin WANG
      The arc spraying technique was adopted to prepare three types of iron-based coatings including 08Mn2Si, 4Cr13, and 65Mn. Meanwhile, the metallurgical microscope and scanning electron microscope (SEM) were used to analyze the microstructure of these coatings. Besides, a DPT-5 dye penetrant was painted on the surface of the coatings to simulate the oil fluid, so as to observe its penetration in the pore structures. The MMU-5G end-face high-temperature wear tester was used to carry out wear-resistance tests on these coatings and give comparison with grey cast irons. The experimental results showed that the 4Cr13 coating exhibited the best wear resistance under oil batch lubrication condition. According to the study of these coating structures, it was discovered that three coatings presented topology-like structures due to the accumulation of flat particles on the matrices. Meanwhile, it was found that zonal oxides were mixed in particles with some unmolten particles, pores, and cracks. Besides, the larger pores were mutually connected by gap-like pores. The existence of FeO in the coating and the pore structures keep oil in acted antifriction effects.


      PubDate: 2016-08-18T15:16:54Z
       
  • Dilatometric Analysis of Irreversible Volume Change during Phase
           Transformation in Pure Iron
    • Abstract: Publication date: August 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 8
      Author(s): Ren-jie ZHAO, Jian-xun FU, Yu-yuan ZHU, Ye-jin YANG, Yan-xin WU
      One assumption underlying the conventional dilatometrie analysis based on the lever rule is that the volume of the specimen changes isotropically during phase transformation, which conflicts with the irreversible length change shown in actual measurements. The contribution of this irreversible effect to the dilation data of pure iron upon heating and cooling was respectively quantified via conversion equations based on lattice parameters. A model considering the elastic strain and creep deformation was established for both the interpretation of the irreversible volume change and the discrepancy between the results measured by a dilatometer and a micrometer.


      PubDate: 2016-08-18T15:16:54Z
       
  • Influence of Spot Welding on Welding Fatigue Properties of CR340 Steel
           Joints
    • Abstract: Publication date: August 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 8
      Author(s): Rui-bin GOU, Wen-jiao DAN, Wei-gang ZHANG
      Total 72 lapped specimens including six different kinds of CR340 steel structures were prepared to study the influence of the spot welding technology on their fatigue characteristics. Fatigue test and group method were employed and performed on each sample to obtain the fatigue experimental data of each structure under four stress levels. The results show that the spot welding technology had a notable impact on the fatigue performance of both the shear and tensile joints. It can significantly improve the fatigue strength of the structure, the consistency and repeatability of experimental data, as well as the stability and reliability of the structure under dynamic load environment. The shear spot welding structure demonstrates the best fatigue performance which is very important for wide application in engineering of this method.


      PubDate: 2016-08-18T15:16:54Z
       
  • Effects of Processing Variables on Microstructure and Yield Ratio of High
           Strength Constructional Steels
    • Abstract: Publication date: August 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 8
      Author(s): Jian KANG, Cheng-ning LI, Xiao-lei LI, Jin-hua ZHAO, Guo YUAN, Guo-dong WANG
      The process of “controlled rolling+relaxation+ultra fast cooling (UFO)” for high strength constructional steel with low yield ratio was presented. Microstructure and corresponding relationship with low yield ratio were investigated. The results showed that the constructional steels with multiphase microstructure of bainitie ferrite, martensite-austenite (M-A) and lath bainite were obtained through the creative process. The grain size decreased with the decrease in finish rolling temperature, which enhanced the strength by the grain refinement strengthening. The proper relaxation treatment promoted the bainitie ferrite lath width and the formation of blocky M-A constituent. In addition, both the tensile and yield strength increased with the decrease in finish rolling temperature and UFC final temperature, but the yield strength increased more significantly than tensile strength, which caused the increase in yield ratio. By using the process of “controlled rollingh+relaxation+ultra fast cooling”, the excellent comprehensive mechanical properties of 780 MPa grade constructional steels of 12 — 40 mm in thickness were achieved.


      PubDate: 2016-08-18T15:16:54Z
       
  • Arc Behavior and Droplet Transfer of CWW CO2 Welding
    • Abstract: Publication date: August 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 8
      Author(s): Zhi-dong YANG, Chen-fu FANG, Yong CHEN, Guo-xiang XU, Qing-xian HU, Xiao-yan GU
      Cable-type welding wire (CWW) CO2 welding is an innovative process arc welding with high quality, high efficiency and energy saving, in which CWW is used as consumable electrode. The CWW is composed of seven wires with a diameter of 1. 2 mm. One is in the center, while others uniformly distribute around it. The diameter of twisted wire is up to 3. 6 mm, which can increase the deposition rate significantly. With continual wire-feeding and melting of CWW, the formed rotating arc improved welding quality obviously. The arc behavior and droplet transfer were observed by the electrical signal waveforms and corresponding synchronous images, based on the high speed digital camera and electrical signal system. The results showed that the shape of welding arc changed from bell arc to beam are with the increase of welding parameter. The droplet transfer mode changed from repelled transfer, globular transfer to projected transfer in turn. Droplet transfer frequency increased from 18. 17 Hz to 119. 05 Hz, while the droplet diameter decreased from 1. 5 times to 0. 3 times of the CWW diameter.


      PubDate: 2016-08-18T15:16:54Z
       
  • An Innovative Approach to Separate Iron Oxide Concentrate from High-sulfur
           and Low-grade Pyrite Cinders
    • Abstract: Publication date: August 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 8
      Author(s): Yon LI, Fu-chun ZHOU, Zhao-xin ZHOU, Zhi-han TIAN, Chao YANG, Xi-ke TIAN
      High-sulfur and low-grade pyritc cinders are the waste products of sulfuric acid manufacturing plants. Many valuable components, such as iron oxide, are contained in pyrite cinders and difficult to be separated and purified just via the high temperature roasting process. Considering this, an innovative method including water-washing, aqua regia leaching, hydrothermal alkali activation and acid-washing was developed. And the effects of different parameters on recovery efficiency of iron oxide were systematically investigated. The optimum parameters were proposed as follows: water rinse-leaching at room temperature for 5 — 20 min, and melting at 160 °C for 2. Oh with NaOH (concentration of 30 mass%), followed by leaching with aqua regia solution (3. 0 vol. %) for 1. 0 h. After the treatment, the content of iron oxides increased from 54. 3 to 96. 0 mass% with the recovery rate exceeding 85%. Meanwhile, calcium sulphate was recovered as the high value-added products by alkali extraction liquid. Furthermore, the phase transformation and microstructure of the samples in the process were studied by physicochemical methods to reveal the separation mechanisms of different components in the pyrite cinders.


      PubDate: 2016-08-18T15:16:54Z
       
  • A New Approach for Refining Carbide Dimensions in M42 Super Hard
           High-speed Steel
    • Abstract: Publication date: August 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 8
      Author(s): Xue-feng ZHOU, Wang-long ZHU, Hong-bing JIANG, Feng FANG, Yi-you TU, Jian-qing JIANG
      Obtaining small carbides is crucial but difficult for high-speed steels. A new approach for refining carbide dimensions in M42 super hard high-speed steel by increasing cooling rate and spheroidizing treatment was proposed. The morphologies and properties of eutectic carbides formed at different cooling rates were investigated by means of scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), transmission electron microscopy (TEM), electron back-scattered diffraction (EBSD) and differential scanning calorimeter (DSC). The results show that eutectic carbides change from a lamellar shape into a curved-rod shape as cooling rate increases. Despite different morphologies, the two carbides are both of M2C type with a hexagonal close-packed structure and display a single crystal orientation in one eutectic colony. The morphology of M2C mainly depends on the growing process of eutectic carbides, which is strongly influenced by cooling rate. Compared with lamellar carbides, M2C carbides with curved-rod shapes are less stable, and decompose into M6C and MC at lower temperatures. They are more inclined to spheroidize during heating, which ultimately and distinguishably refines the carbide dimensions. As small carbides are much easier to dissolve into matrices during austenization, the process described herein improves the supersaturation of alloying elements in martensite, which leads to an increment of hardness in M42 steel.


      PubDate: 2016-08-18T15:16:54Z
       
  • On-line Ladle Lining Temperature Estimation by Using Bounded Jacobian
           Nonlinear Observer
    • Abstract: Publication date: August 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 8
      Author(s): G. PHANOMCHOENG, S. CHANTRANUWATHANA, P. CHARUNYAKORN
      The knowledge of transient temperature of the ladle wall is a key factor in optimizing energy consumption in steelmaking process. The transient temperature needs to be estimated. A nonlinear lumped parameter model was used to model the thermal dynamics of the ladle. Then, the bounded Jacobian nonlinear observer was utilized to estimate the temperature. With this method, the estimation model became a closed-loop model and the observer gains were obtained by solving linear matrix inequalities and simply implemented to the system. Comparison between the simulation and recorded data at a participating steel plant in Thailand showed that the nonlinear observer accurately estimated the temperature of the ladle lining. This estimated temperature was very useful in determining suitable tapping temperature for energy conservation and steel quality.


      PubDate: 2016-08-18T15:16:54Z
       
  • Desulfurization Behavior and Mechanism of CaO-saturated Slag
    • Abstract: Publication date: August 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 8
      Author(s): Jian-fei XU, Fu-xiang HUANG, Xin-hua WANG
      To develop a high-efficiency desulfurizer for the production of pipeline steel with the LD-RH-CC process, the desulfurization efficiency and mechanism of CaO-saturated slag were studied using a vacuum-induction furnace and Si-Mo electric resistance furnace. The results show that the desulfurization ability for slag with a small amount of solid CaO was highly enhanced under conditions of satisfied kinetics. The desulfurization reaction of CaO-saturated slag depended on the liquid slag rather than the solid CaO, as sulfur was not detected inside the solid CaO. The desulfurization efficiency of CaO-saturated slag was also influenced by the amount of residual liquid slag and its sulfur absorption ability. The sulfur absorption ability of CaO-CaF2 slag was analyzed to be much higher than that of CaO-Al2O3-CaF2-(SiCO2) slag. Moreover, the effect of solid CaO on the desulfurization kinetics was evaluated and the application conditions of CaO-saturated slag were discussed.


      PubDate: 2016-08-18T15:16:54Z
       
  • Prediction of Maximum Section Flattening of Thin-walled Circular Steel
           Tube in Continuous Rotary Straightening Process
    • Abstract: Publication date: August 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 8
      Author(s): Zi-qian ZHANG
      Cross-sectional ovalization of thin-walled circular steel tube because of large plastic bending, also known as the Brazier effect, usually occurs during the initial stage of tube's continuous rotary straightening process. The amount of ovalization, defined as maximal cross section flattening, is an important technical parameter in tube's straightening process to control tube's bending deformation and prevent buckling. However, for the lack of special analytical model, the maximal section flattening was determined in accordance with the specified charts developed by experienced operators on the basis of experimental data; thus, it was inevitable that the localized buckling might occur during some actual straightening operations. New normal strain component formulas were derived based on the thin shell theory. Then, strain energy of thin-walled tube (per unit length) was obtained using the clastic-plastic theory. A rational model for predicting the maximal section flattening of the thin-walled circular steel tube under its straightening process was presented by the principle of minimum potential energy. The new model was validated by experiments and numerical simulations. The results show that the new model agrees well with the experiments and the numerical simulations with error of less than 10%. This new model was expected to find its potential application in thin-walled steel tube straightening machine design.


      PubDate: 2016-08-18T15:16:54Z
       
  • Effects of Different Oxidants on HCl-based Pickling Process of 430
           Stainless Steel
    • Abstract: Publication date: August 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 8
      Author(s): Qiong XIE, Pei-yang SHI, Cheng-jun LIU, Mao-fa JIANG
      To shorten the time required for the pickling process and to enhance the quality of ferritic stainless steel plates, the effects of oxidants including hydrogen peroxide (H2O2), potassium permanganate (KMnO4), and potassium chlorate (KClO3) on the pickling behavior in HCl-based electrolyte as well as the surface quality of hot-rolled and blasted 430 stainless steel (430-SS) were studied. Experiments were conducted using mass-loss tests, microstructure analyses, potcntiodynamic polarization curves, and electrochemical impedance spectroscopy measurements. The results showed that the addition of oxidants substantially accelerated the pickling process of 430-SS by enhancing the cathodic reaction rate and reducing the charge transfer resistance. In electrolytes comprising 5 — 8 mass% HCl at a temperature of 40 — 60 °C and at the same concentration within the range from 0 to 2 mass%, H2O2 was demonstrated to be superior to KMnO4 and KClO3 in accelerating the pickling process. The surface quality of 430-SS pickled in the presence of H2O2 was better than those of specimens pickled in the presence of KMnO4 and KClO3 when the removal of the oxide layer, intergranular corrosion, and surface roughness were collectively considered. When 1 mass% H2O2 was added, the mass loss rate of 430-SS was increased by 629% and no residual oxide layer or intergranular corrosion was observed on the surface of the steel; in addition, the roughness was only 1. 7 μm. H2O2 was determined to be a better oxidant than KMnO4 and KCIO.3 when the pickling process, surface quality, solution recycling, and environment protection were considered as a whole.


      PubDate: 2016-08-18T15:16:54Z
       
  • Numerical Simulation and Experimental Study of an Ultrasonic Waveguide for
           Ultrasonic Casting of 35CrMo Steel
    • Abstract: Publication date: August 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 8
      Author(s): Gen LIANG, Chen SHI, Ya-jun ZHOU, Da-heng MAO
      To achieve ultrasonic casting of 35CrMo steel, the waveguide unit for introducing ultrasound into liquid steel was studied numerically and experimentally. The structure and length of the ultrasonic waveguide were optimized by modal analysis. The simulation results showed that a T-shaped waveguide unit matched the vibrational system better than an L-shaped unit. The performance of T-shaped waveguide unit was optimized when the length of the ultrasound radiator was 135 mm. The performance of the T-shaped waveguide unit was investigated in ultrasonic casting experiments, and the effect of ultrasound on the microstructure of 35CrMo steel was examined. The experimental results showed that the T-shaped waveguide was able to successfully introduce ultrasound into the 35CrMo melt. In addition, the use of a silicon nitride ceramic radiator avoided high-temperature corrosion in the molten metal. The microstructure of the treated area was significantly refined and equiaxed grains were obtained. The results represented a novel method for ultrasonic casting of steel.


      PubDate: 2016-08-18T15:16:54Z
       
  • Effect of Scale Formation on Copper Enrichment Behavior in Continuously
           Cast Slab
    • Abstract: Publication date: August 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 8
      Author(s): Nan WANG, Jin XU, Shan YU, Guang-zong ZHANG, Guang-hao CHEN, Min CHEN
      Copper enrichment behavior in continuously cast slab induced by scale formation during continuous cooling was experimentally investigated, and the effects of initial slab surface temperature and oxygen potential in atmosphere were discussed. The results showed that a loose scale adhered to the substrate was formed in H2O-N2 atmosphere at higher slab surface temperature compared to a gap formed between the scale and the steel substrate after continuous cooling in H2O-O-O2-N2 atmosphere. Under the condition of continuous cooling in H2O-N2 atmosphere, the copper enrichment occurred both within the loose scale and at the scale/steel interface with simultaneous Ni enrichment near the interface at higher slab surface temperature. The combined effects of the loose scale and nickel enrichment were thought to promote the back-migration of Cu-rich phase from the interface and occlusion within the scale layer. While in H2O-O2-N2 atmosphere, the Cu enrichment was found on the steel side and the formed gap prevented the migration of Cu to the scale.


      PubDate: 2016-08-18T15:16:54Z
       
  • Effects of Chromium Addition on Preparation and Properties of Bulk
           Cementite
    • Abstract: Publication date: August 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 8
      Author(s): Bao-chao ZHENG, Zhi-fu HUANG, Jian-dong XING, Yi-yang XIAO, Xiao FAN, Yong WANG
      Bulk cementites with the Cr contents of 0, 3. 01, 6. 03, 8. 22, and 11. 51 mass% were prepared by mechanical alloying (MA) and spark plasma sintering (SPS). The results indicated that when the Cr content was low (3. 01 mass%), the phases were composed of cementite with a small amount of α-Fe at a sintering temperature of 1 173 K, but the microstructure became single-phase alloyed cementite as the Cr content was further increased. It showed that microaddition of Cr was beneficial for promoting the formation of cementite. Furthermore, the mechanical performance of cementite can be greatly affected by the variation of Cr content. The hardness, elastic modulus and elastic recovery presented a remarkably increasing tendency with the addition of Cr, and the maximum micro-hardness and elastic modulus values reached 1 070. 74 HV and 199. 32 GPa, respectively, which were similar to the precipitation phase (cementite) obtained by melting and casting techniques. Moreover, when the Cr content was below 11. 51 mass%, the crystal structure of Fe3C-type cementite would not change with increasing the Cr content. A Cr atom replaced an Fe atom in the lattice of the cementite, and voids appeared when Cr was doped into the cementite at content of about 11.51 mass%, causing the relative density to decrease.


      PubDate: 2016-08-18T15:16:54Z
       
  • Precipitation of μ Phase in Nickel-based Powder Metallurgy Superalloy
           FGH97
    • Abstract: Publication date: August 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 8
      Author(s): Li-ming TAN, Yi-wen ZHANG, Jian JIA, Shou-bo HAN
      The precipitation behavior of topological close-packed (TCP) μ phase in powder metallurgy (P/M) nickel-based supcralloy FGH97 was investigated. The results showed that proper addition of solution strengthening elements, such as Co, Cr, W, Mo, improved tensile strength, while excessive addition of those elements facilitated the precipitation of μ phase, which seriously aggravated the plasticity of the P/M superalloy. For the heat-treated specimens, the relationship between critical aging time (when μ started to precipitate), aging temperature, and the average electron vacancy number of γ matrix was established.


      PubDate: 2016-08-18T15:16:54Z
       
  • Abrasive Wear Behaviors of Light-weight Austenitic Fe-24Mn-7Al-1C Steel
           and Mn13Cr2 Steel
    • Abstract: Publication date: August 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 8
      Author(s): Shi-guang PENG, Ren-bo SONG, Zhi-dong TAN, Chang-hong CAI, Ke GUO, Zhong-hong WANG
      The impact abrasive wear behaviors of light-weight austenitic Fe-24Mn-7Al-1C steel with increasing impact wear conditions were studied by comparing with the modified Had field (Mn13Cr2) steel. Wear tests were performed with the MLD-10 abrasive wear testing machine. Main parameters such as impact energy, impacting frequency and wear time were evaluated. To explore the abrasive wear behaviors under different impact energies, the parameters including mass loss, wear resistance and hardness were evaluated in detail. The microstructures of the steels were further analyzed using optical microscopy (OM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). Results showed that the light-weight austenitic Fe-24Mn-7Al-1C steel had a better wear resistance than Mn13Cr2 steel under the impact energy tested. The wear resistance of light-weight austenitic Fe-24Mn-7Al-1C steel was about 1. 09 — 1. 17 times as high as that of Mn13Cr2 steel under low and medium impact energy (0. 5 —2.0 J) conditions, and l. 41 times under high impact energy (4. 0 J) condition. In Mn13Cr2 steel, the evolution of dislocation substructure with increasing impact energy showed typical stacking fault, interaction of twins and dislocations, as well as mechanical twins. The high work-hardening rate in Fe-24Mn-7Al-1C steel was caused by Taylor lattice and high density of dislocation tangles.


      PubDate: 2016-08-18T15:16:54Z
       
  • Rolling Contact Fatigue Properties of SAE 8620 Steel after Case
           Carburizing
    • Abstract: Publication date: July 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 7
      Author(s): Yan-guang CAO, Le XU, Gou-qiang ZHANG, Jie SHI, Mao-qiu WANG
      Rolling contact fatigue (RCF) properties of SAE 8620 steel after case carburizing have been investigated under two contact stresses of 4.0 and 5.5 GPa. Results show that the RCF life ranges from 2.5 × 106 to 3 × 107 cycles under the contact stress of 5.5 GPa, while it can be more than 1 × 108 cycles under the contact stress of 4.0 GPa. The rated fatigue life L 10 (lives with the 10% failure) is also drastically shortened from 9.8 × 106 to 5.4 × 105 cycles when the contact stress is increased from 4.0 to 5.5 GPa. Theoretical calculations and fractographs show that the maximum shear stress and the contact area increase with increasing the contact stress, making RCF tend to occur earlier.


      PubDate: 2016-07-03T15:01:47Z
       
  • Weldability of 1000 MPa Grade Ultra-low Carbon Bainitic Steel
    • Abstract: Publication date: July 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 7
      Author(s): Qing-mei JIANG, Xiao-qiang ZHANG, Li-qing CHEN
      Maximum hardness test in weld heat-affected zone (HAZ), oblique Y-groove cracking test and mechanical property test of welding joint of 1000 MPa grade ultra-low carbon bainitic steel were carried out, so as to research the weldability of the steel. The results show that the steel has lower cold cracking sensitivity, and preheating temperature of 100 °C can help completely eliminate cold cracks, generating good process weldability. The increase of preheating temperature can reduce the hardening degree of heat-affected zone. The strength of welding joint decreases and hardness reduces when heat inputs increase, and excellent mechanical properties can be obtained when low welding heat inputs are used. Fine lath bainites of different orientations combined with a few granular bainites that effectively split the original coarse austenite grains are the foundation of good properties.


      PubDate: 2016-07-03T15:01:47Z
       
  • Effects of γ-irradiation and Deformation Temperature on Tensile
           Properties of Pb-2 mass% Sb Alloy
    • Abstract: Publication date: July 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 7
      Author(s): Gh MOHAMMED, S. EI-GAMAL
      Effects of γ-irradiation and deformation temperature (T) on the tensile properties of Pb-2 mass% Sb alloys were studied. The samples were annealed at 458 K for 2 h in air, then water quenched after they were γ-irradiated (the different doses were 0.5, 1.0, 1.5, and 2.0 MGy). The tensile properties were performed using stress-strain measurements at a constant strain rate (1.2 × 10−3 s−1) and at different T (303 − 393 K). It was found that at constant dose, the fracture stress (σF) decreases while the fracture strain (ɛF) increases as T increases. At particular T, σF increases while ɛF decreases with increasing dose. The strain-hardening exponent (n), which is the slope of the relation between ln(σ) and ln(ɛ) of the parabolic part of the stress-strain curve, was determined and its values increase as T increases and decrease as the dose increases. The value of the activation energy increases as the dose increases from 0.07 eV for un-irradiated sample to 0.1 eV for the 2 MGy-irradiated sample. These values are in accordance with that needed for dislocation movement and ordering process. An interpretation of the results was given, based on the creation of point and line defects due to γ-irradiation, and that results in a distribution of beta phase (Sb-phase), leading to a difficulty in the movement of dislocations, so there is an increase in alloy hardness.


      PubDate: 2016-07-03T15:01:47Z
       
  • Green Approach to Corrosion Inhibition of Mild Steel by Lignin Sulfonate
           in Acidic Media
    • Abstract: Publication date: July 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 7
      Author(s): Muna A. ABU-DALO, Nathir A.F. AL-RAWASHDEH, Ahmed A. MUTLAQ
      The inhibition effect of lignin sulfonate against corrosion for mild steel in acidic solution has been examined by means of FTIR (fourier transform infrared spectroscopy), FAA (flame atomic absorption) spectroscopy, SEM (scanning electron microscope), EDS (energy dispersive X-ray spectroscopy), and mass loss techniques. The results revealed that lignin is a beneficial inhibitor for mild steel corrosion in acidic medium. It has been further found that Langmuir adsorption isotherm is obeyed by the tested lignin's adsorption over the surface of mild steel. The range of inhibition efficiency (IE) in 2 mol · L−1 HCl was found to be 75.88 % − 87.88% for Reax 88A, 10.72% − 60.32% for Reax 88B, and 51.32% − 63.03% for Reax 100M, after immersed at 298 K for 24 h time.


      PubDate: 2016-07-03T15:01:47Z
       
  • Effect of 0.5 mass% Cu Addition on Ductility and Magnetic Properties of
           Fe-6. 5Si Alloy
    • Abstract: Publication date: July 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 7
      Author(s): Zhao-yang CHENG, Jing LIU, Wen-si CHEN, Jia-chen ZHU, Xi-feng LIN, Zhi-dong XIANG
      The effect of adding 0.5 mass% Cu on ductility and magnetic properties of Fe-6. 5Si (mass%) alloy was investigated. The alloys with and without 0.5 mass% Cu addition were warm rolled into thin sheets of thickness no more than 0.3 mm at temperature below 600 °C. It was found that the alloy with 0.5 mass% Cu addition was more easily warm rolled than Cu-free alloy. Tensile tests were carried out to further investigate this phenomenon, which confirmed that the ductility of the alloy with 0.5 mass% Cu addition was significantly higher than that of Cu-free alloy at 550 °C. Based on the results of transmission electron microscopy analysis, the ductility increase of the alloy with 0.5 mass% Cu addition was attributed to the effect of Cu on the promotion of dynamic recovery and suppression of long-range order in the alloy during warm rolling process. It was also observed that the iron loss was lower and inductance was higher for the alloy with 0.5 mass% Cu addition. Thus, it can be concluded that adding a suitably small amount of Cu would not only increase the ductility of Fe-6. 5Si alloy at warm rolling temperatures but also improve its magnetic properties.


      PubDate: 2016-07-03T15:01:47Z
       
  • Source and Control of Nitrogen for X70 Pipeline Steel
    • Abstract: Publication date: July 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 7
      Author(s): Min WANG, Yan-ping BAO
      The effects of some key factors on nitrogen absorption during the smelting process of X70 pipeline steel were studied, and the source of nitrogen pick-up was analyzed to find the bottleneck for nitrogen control. A series of measures were put forward to decrease the nitrogen pick-up. The results indicated that an exponential relationship existed between the nitrogen absorption index and the free oxygen in molten steel. Nitrogen absorption index could decrease below 0.3 when free oxygen in molten steel was above 100 × 10−6 after tapping. For low sulfur killed steel, the nitrogen absorption ratio and sulfur content satisfied a linear relationship with a slope of −0.007. Low free-oxygen and sulfur were beneficial to the deep desulfurization during vacuum treatment. The contradiction of high desulfurization ratio and low nitrogen pick-up during LF process could be resolved by skimming oxidizing slag after tapping and making new high basicity top slag. After optimization, the average content of nitrogen in final product decreased from 46 × 10−6 to 35 × 10−6.


      PubDate: 2016-07-03T15:01:47Z
       
  • Microstructural Evolution and Performance of In-situ Ag-Ni Composite after
           Solidification under Electromagnetic Stirring and Deformation
    • Abstract: Publication date: July 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 7
      Author(s): Lin ZHANG, Ke HAN, Tian-nan MAN, En-gang WANG, Xiao-wei ZUO
      The effect of electromagnetic stirring (EMS) on microstructure and performance of Ag-8 mass% Ni composite was investigated under both solidified and deformed conditions. Without EMS, the Ag matrix formed short, thick dendrites in the ingot; whereas with EMS, dendrites were long and slim. Ni phase mainly formed particles or ribbons, distributed along boundaries between dendrite arms. Cold drawing of the solidified Ag-Ni ingots, both with and without EMS, produced high strength in-situ metal-matrix composite (MMC) consisting of Ag matrix reinforced by Ni ribbons. EMS improved the ductility of the composite, consequently enhancing its drawability and strength. EMS also increased the electrical conductivity in both solidified ingots and deformed in-situ composite wires. In both cases, hardness and tensile strength remained high. A model based on a combination of the modified linear rule of mixtures and the Hall-Petch relationship was used to rationalize the tensile strength and hardness with respect to its fabrication parameters and the microstructure of Ag-Ni in-situ composite.


      PubDate: 2016-07-03T15:01:47Z
       
  • Microstructure and Wear Properties of Fe-based Amorphous Coatings
           Deposited by High-velocity Oxygen Fuel Spraying
    • Abstract: Publication date: July 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 7
      Author(s): Gang WANG, Ping XIAO, Zhong-jia HUANG, Ru-jie HE
      Fe-based powder with a composition of Fe12.87 Cr13.98 Mo16.33 C13.91 B8.88 (at. %) was used to fabricate coatings by high-velocity oxygen fuel spraying. The effects of the spraying parameters on the microstructure and the wear properties of the Fe-based alloy coatings were systematically studied. The results showed that the obtained Fe-based coatings with a thickness of about 400 μm consisted of a large-volume amorphous phase and some nanocrystals. With increasing the fuel and oxygen flow rates, the porosity of the obtained coatings decreased. The coating deposited under optimized parameters exhibited the lowest porosity of 2.8%. The excellent wear resistance of this coating was attributed to the properties of the amorphous matrix and the presence of nanocrystals homogeneously distributed within the matrix. The wear mechanism of the coatings was discussed on the basis of observations of the worn surfaces.


      PubDate: 2016-07-03T15:01:47Z
       
  • Precipitation Behavior of FeTiP in Ti-added Interstitial Free High
           Strength Steels
    • Abstract: Publication date: July 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 7
      Author(s): Juan JIA, Wei-wei ZHU, Xin-li SONG, Ze-xi YUAN
      The precipitation behavior of FeTiP in interstitial free high strength (IFHS) steels has been studied by using a transmission electron microscope (TEM). The results show that the TiC particles, appearing at earlier stage, are more stable than the FeTiP ones during recrystallization annealing at the two given temperatures (810 °C and 840 °C). Therefore, the FeTiP particles can only be observed in the steels with sufficient amount of Ti. There is a critical forming time for the FeTiP, which is between 90 – 120 s at 810 °C and 60 – 90 s at 840 °C. The precipitation of FeTiP involves two steps, i.e. the formation of FeTi precursors and the diffusion of P. The formier step determines the reliance of Ti content for the precipitation of FeTiP, whereas the latter step leads to the difference in the critical annealing time.


      PubDate: 2016-07-03T15:01:47Z
       
  • Growth Kinetics of Laves Phase and Its Effect on Creep Rupture Behavior in
           9Cr Heat Resistant Steel
    • Abstract: Publication date: July 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 7
      Author(s): Zhi-xin XIA, Chuan-yang WANG, Chen LEI, Yun-ting LAL, Yan-fen ZHAO, Lu ZHANG
      The effects of Laves phase formation and growth on creep rupture behaviors of P92 steel at 883 K were studied. The microstructural evolution was characterized using scanning electron microscopy and transmission electron microscopy. Kinetic modeling was carried out using the software DICTRA. The results indicated Fe2 (W, Mo) Laves phase has formed during creep with 200 MPa applied stress at 883 K for 243 h. The experimental results showed a good agreement with thermodynamic calculations. The plastic deformation of laths is the main reason of creep rupture under the applied stress beyond 160 MPa, whereas, creep voids initiated by coarser Laves phase play an effective role in creep rupture under the applied stress lower than 160 MPa. Laves phase particles with the mean size of 243 nm lead to the change of creep rupture feature. Microstructures at the vicinity of fracture surface, the gage portion and the threaded ends of creep rupture specimens were also observed, indicating that creep tensile stress enhances the coarsening of Laves phase.


      PubDate: 2016-07-03T15:01:47Z
       
  • Evaluation on Fatigue Performance and Fracture Mechanism of Laser Welded
           TWIP Steel Joint Based on Evolution of Microstructure and Micromechanical
           Properties
    • Abstract: Publication date: July 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 7
      Author(s): Li-li MA, Ying-hui WEI, Li-feng HOU, Chun-li GUO
      The fatigue performance and fracture mechanism of laser welded twinning induced plasticity (TWIP.) steel joint were investigated experimentally based on the evolution of microstructure and micromechanical properties. The optical microscopy was used to analyze the evolution of microstructure. The variation of composition and phase structure of fusion zone were detected by energy dispersive X-ray and X-ray diffraction spectrometers. The micromechanical behaviors of the various zones were characterized using nanoindentation. The static tensile test and high cycle fatigue test were performed to evaluate the mechanical properties of welded joint and base metal. The microstructures, tensile properties and fatigue strength of base metal as well as welded metal were analyzed. The fatigue fracture surfaces of base metal and welded joint were observed by means of scanning electron microscopy, in order to identify fatigue crack initiation sites and propagation mechanisms. Moreover, the fatigue fracture characteristics and mechanisms for the laser welded TWIP steel joints were analyzed.


      PubDate: 2016-07-03T15:01:47Z
       
  • Curvature and Residual Stress Analysis in Rotational Leveling of Bars
    • Abstract: Publication date: July 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 7
      Author(s): Yong-qin WANG, Zhi-fang LIU, Hen-gan OU, Yuan-xin LUO, Xing-chun YAN
      Leveling process plays an important role in delivering the desired material properties and product standards. An analytical method for the rotational leveling process of bars was presented. First, each cross section of the bar in the leveling area was discretized with the roller gap-curvature relations established in both planes XY and XZ. Second, a numerical procedure with two steps was developed to simulate both pressing and leveling processes. This approach can be easily implemented to produce simulation results of the curvature and trajectory distributions during the leveling process, as well as the bending and residual stresses. It is found that curvature and trajectory distributions follow a sine-shape due to the characteristic of rotational movement, which also results in a helical pattern of residual stress after leveling. Based on the results obtained, it is also observed that the rotational movement is beneficial for adding the number of bending cycle. This is the reason why there are only a few pairs of rollers on the bar leveler.


      PubDate: 2016-07-03T15:01:47Z
       
  • Influence of Mechanical Activation on Acid Leaching Dephosphorization of
           High-phosphorus Iron Ore Concentrates
    • Abstract: Publication date: July 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 7
      Author(s): De-qing ZHU, Hao WANG, Jian PAN, Cong-cong YANG
      High pressure roll grinding (HPRG) and ball milling were compared to investigate the influence of mechanical activation on the acid leaching dephosphorization of a high-phosphorus iron ore concentrate, which was manufactured through magnetizing roasting-magnetic separation of high-phosphorus oolitic iron ores. The results indicated that when high-phosphorus iron ore concentrates containing 54.92 mass % iron and 0.76 mass % phosphorus were directly processed through acid leaching, iron ore concentrates containing 55.74 mass% iron and 0.33 mass % phosphorus with an iron recovery of 84.64 % and dephosphorization of 63.79 % were obtained. When high-phosphorus iron ore concentrates activated by ball milling were processed by acid leaching, iron ore concentrates containing 56.03 mass % iron and 0.21 mass% phosphorus with an iron recovery of 85.65% and dephosphorization of 77.49 % were obtained. Meanwhile, when high-phosphorus iron ore concentrates activated by HPRG were processed by acid leaching, iron ore concentrates containing 58.02 mass% iron and 0.10 mass% phosphorus were obtained, with the iron recovery reaching 88.42% and the dephosphorization rate reaching 88.99%. Mechanistic studies demonstrated that ball milling can reduce the particle size, demonstrating a prominent reunion phenomenon. In contrast, HPRG pretreatment contributes to the formation of more cracks within the particles and selective dissociation of iron and P bearing minerals, which can provide the favorable kinetic conditions to accelerate the solid-liquid reaction rate. As such, the crystal structure is destroyed and the surface energy of mineral particles is strengthened by mechanical activation, further strengthening the dephosphorization.


      PubDate: 2016-07-03T15:01:47Z
       
  • Influences of Technological Parameters on Smelting-separation Process for
           Metallized Pellets of Vanadium-bearing Titanomagnetite Concentrates
    • Abstract: Publication date: July 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 7
      Author(s): En-hui WU, Rong ZHU, Shao-li YANG, Ian MA, Jun LI, Jing HOU
      The smelting-separation process for metallized pellets of vanadium-bearing titanomagnetite concentrates was studied. The influences of smelting temperature, smelting time, and the basicity of the metallized pellet on vanadium and iron recovery were investigated. The characteristics of titanium slag were analyzed using X-ray diffraction, energy dispersive spectroscopy, and mineralographic microscopic analysis. The results demonstrate that appropriate increases in smelting temperature and smelting time can improve the vanadium and iron recovery from metallized pellets and are beneficial for the slag-iron separation. Although increasing the basicity of the metallized pellet can considerably improve the vanadium and iron recovery, the TiO2 grade of titanium slag was decreased. Under the optimal conditions, 90.17% of vanadium and 92.98% of iron in the metallized pellet were recovered, and the TiO2 grade of titanium slag was 55.01%. It was found that anosovite, augite, spinel, glassiness, and metallic iron were the main mineral phases of the titanium slag.


      PubDate: 2016-07-03T15:01:47Z
       
  • Viscosity and Structure Changes of CaO-SiO2-Al2O3-CaF2 Melts with
           Substituting Al2O3 for SiO2
    • Abstract: Publication date: July 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 7
      Author(s): Guo-hua ZHANG, Yu-lan ZHEN, Kuo-chih CHOU
      During the smelting process of the high Al steels, the reaction between SiO2 in molten slag and dissolved aluminum in liquid steel always takes place. This aluminathermic reduction reaction will lead to the substitution of 1 mol SiO2 for 2/3 mol Al2O3. Therefore, the investigations about the influence of the ratio of Al2O3 to SiO2 on viscosity and structure changes of mould flux during this process are very necessary. The viscosity variation of CaO-SiO2-Al2O3-CaF2 melts was studied by changing compositions considering the aluminathermic reduction reaction. It was found that viscosity increased monotonously with gradually increasing the substitution extent. According to the Raman analysis, the substitution of Al2O3 for SiO2 leads to the decrease of non-bridging oxygen but the increase of bridging oxygen. Therefore, degree of polymerization and viscosity increase as the substitution extent increases. By comparing the measured viscosities with the model calculated values, it was found that both the recently developed Zhang's model and Roboud model could describe the viscosity variation behavior of CaO-SiO2-Al2O3-CaF2 melts very well.


      PubDate: 2016-07-03T15:01:47Z
       
  • Advances in Investigation of Fe-based Glass-forming Alloy Melts
    • Abstract: Publication date: June 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 6
      Author(s): Hui GAO, Bang-shao DONG, Shao-xiong ZHOU
      Continuous precision casting is an important trend in modern industrialization. Clustering effects in glass-forming metallic liquids tremendously influence the properties of rapidly quenched ribbons; therefore, much attention has been paid to the study of Fe-based glass-forming melts at high temperatures. Recent investigations of these melts are categorized and reviewed. It is concluded that more efforts are still required to reveal the discipline of amorphization brought about by rapid quenching of Fe-based glass-forming melts.


      PubDate: 2016-06-15T05:54:59Z
       
  • Effect of Alloying Method on Microstructure and Wear Resistance of
           Fe-Cr-V-B Based Alloy
    • Abstract: Publication date: June 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 6
      Author(s): Yu MA, Ying LIU, Jun LI, Hui ZHANG, Hao YANG
      The microstructure and wear behavior of Fe-Cr-V-B based alloy was investigated. Each of the specimens was characterized by metallographic techniques and hardness test. Phase analysis of alloy was performed by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The results showed that the microstructure of Fe-Cr-V-B based as-cast alloy containing 8.6 mass% V was composed of α-(Fe, Cr) solid solution, VC carbides, and V3B4 borides, whereas the as-cast alloy containing 24.8 mass% Cr was composed of α-(Fe, Cr) solid solution and V3B4, borides; the eutectic V3B4, borides mainly comprise M2B-type borides (M presents Fe and Cr). The existence of a large amount of V atoms affects the growth pattern of eutectic borides, which mainly display rod-like and grainy structure. The wear behavior of the experimental alloy has been investigated using pin-on-disk type friction and wear apparatus. The comparison of experimental results indicated that the relative wear resistance of the alloy containing 8.6 mass% V after destabilization heat treatment in a conventional furnace at 1373 K for 2 h was about six times higher than that of the high chromium (19 mass%) cast iron.


      PubDate: 2016-06-15T05:54:59Z
       
  • Corrosion Behavior of Cr Micro-alloyed Corrosion-resistant Rebar in
           Neutral Cl−-containing Environment
    • Abstract: Publication date: June 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 6
      Author(s): Dan SONG, Wei SUN, Jin-yang JIANG, Han MA, Jian-chun ZHANG, Zhao-jun CHENG
      A new low-cost corrosion-resistant rebar (HRB400R) was designed and fabricated by Cr micro-alloying. The HRB400R rebar had uniform distribution of Cr element in ferrite grains. The corrosion behavior of the rebar in the neutral Cl−-containing environment was studied systematically, and the improved corrosion resistance of the HRB400R rebar was revealed. According to the corrosion-morphology observation and electrochemical monitoring during the constant immersion corrosion in the 3.5 mass% NaCl solution, the HRB400R rebar presented alleviated corrosion damage, nobler E corr, lower I corr, and larger R t values, and these phenomena were more remarkable in the initial corrosion period. The elevated electrode potential of the rebar, caused by the solid-solution of Cr micro-alloying in the ferrite grains, was the key to the corrosion-resistance improvement. The HRB400R rebar also presented much lower mass-loss rate in the salt spray corrosion test. Besides the elevated corrosion resistance of the matrix, the doping and enrichment of Cr element in the rust layer was another factor for the higher corrosion resistance, which retarded the penetration of aggressive medium through the rust layer.


      PubDate: 2016-06-15T05:54:59Z
       
  • Plasma Transferred Arc Surface Alloying of Cr-Ni-Mo Powders on Compacted
           Graphite Iron
    • Abstract: Publication date: June 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 6
      Author(s): Ji-jun FENG, Chun-xu PAN, Liu-lin LU, Qi-wen HUANG, Hua-tang CAO
      A Cr-Ni-Mo overlayer was deposited on the surface of compacted graphite iron (CGI) by the plasma transferred arc (PTA) alloying technique. The microstructure of Cr-Ni-Mo overlayer was characterized by optical microscopy (OM), scanning electron microscopy (SEM) equipped with energy dispersive spectroscopy (EDS), and X-ray diffractometer (XRD). Results show that the cross-section consists of four regions: alloying zone (AZ), molten zone (MZ), heat affected zone (HAZ), and the substrate (SUB). The microstructure of AZ mainly consists of cellular γ-(Fe, Ni) solid solution, residual austenite and a network of eutectic Cr7C3 carbide while the MZ area has a typical feature of white cast iron (M3C-type cementite). The martensite/ledeburite double shells are observed in the HAZ. With decreasing the concentration of Cr-Ni-Mo alloys, the fracture mode changes from ductile in the AZ to brittle in the MZ. The maximum hardness of the AZ (450 HV0.2) is lower than that of the MZ (800 HV0.2). The eutectic M3C and M7C3 carbides increase the microhardness, while the austenite decreases that of the AZ.


      PubDate: 2016-06-15T05:54:59Z
       
  • Effect of Cr on Characteristic of Rust Layer Formed on Low Alloy Steel in
           Flow-accelerated Corrosion Environment
    • Abstract: Publication date: June 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 6
      Author(s): Feng CHAI, Shan JIANG, Cai-fu YANG
      The flow-accelerated corrosion experiments were carried out to research the effect of Cr on the rust layers formed on the carbon steel and Cr-containing steel, as well as the structure of rust layer of the two experimental steels. The influence of Cr on the flow-accelerated corrosion resistance and the corrosion morphology of inner rust layer formed on the Cr-containing steel were studied by the methods of polarization curves, scanning electron microscope, transmission electron microscope, and X-ray photoelectron spectroscope. The distribution of Cr and its form of existence in the inner rust layer were analyzed. The results show that corroded mass loss of Cr-containing steel is lower than that of carbon steel and its inner rust layer is compact. Cr exists in the form of Fe2CrO4 and is enriched in the inner rust layer. This concentration could make the inner rust layer exhibit the tendency of amorphous. This phenomenon is related to fine Fe2CrO4. The inner rust layer becomes more compact because of the formation of fine Fe2CrO4, and the protectiveness of inner rust layer could be improved remarkably.


      PubDate: 2016-06-15T05:54:59Z
       
  • Relationship between Crystal Structure of Inclusions and Formation of
           Acicular Ferrites
    • Abstract: Publication date: June 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 6
      Author(s): Zhi-min CUI, Li-guang ZHU, Yuan-liang LI, Qing-jun ZHANG, Chun-liang YAN, Wen-ling MO
      The formation mechanism of intragranular ferrites with acicular morphology was discussed. The ferrites were characterized by scanning electron microscopy. The results showed that the ferrites had an acicular structure with radial, symmetrical, and acicular laths, and that the inclusions were the nucleation sites of the intragranular acicular ferrites. Transmission electron microscopy (TEM) was used to characterize the inclusions. The results of TEM with energy dispersive spectroscopy and TEM-selected area electron diffraction indicated that the complex inclusions consisted of Ti-Al complex oxides and MnS. The jagged edges of the complex inclusions can be ascribed to the effects of the crystal structure. The stabilization energy U of the coordination polyhedron growth units varies with the type of connection according to the calculation results. A larger U corresponds to more stable growth units, which induces the preferentially oriented growth of inclusions, at which point acicular ferrites are formed.


      PubDate: 2016-06-15T05:54:59Z
       
  • Effects of TMCP Schedule on Precipitation, Microstructure and Properties
           of Ti-microalloyed High Strength Steel
    • Abstract: Publication date: June 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 6
      Author(s): Xiang-dong HUO, Lie-jun LI, Zheng-wu PENG, Song-jun CHEN
      Using the similar compositions of the Ti-microalloyed high-strength steels produced by the thin-slab casting process of compact strip production (CSP), four thermo-mechanical control processes (TMCP) after the simulated thick-slab casting, i. e. the two hot rolling routes and the two cooling processes, were designed, aiming at achieving the same mechanical properties as the thin strip products. The final microstructures after the four TMCP processes were examined by optical microscope (OM), scanning electron microscope (SEM) and transmission electron microscope (TEM). The tensile properties and Charpy impact energy were measured correspondingly. Strain-induced TiC precipitation was found in the two-stage rolling route with the finish rolling temperature at low levels, leading to grain refinement due to the pinning effect during austenite recrystallization. Precipitation hardening in ferrite was observed when a period of isothermal holding was applied after hot rolling. It could be concluded that both finish rolling temperature and the subsequent isothermal holding temperature were crucial for the achieved strength level due to the combined effect of grain refinement and precipitation hardening. At the same time, it was found that the isothermal holding led to poor impact toughness because of remarkable precipitation hardening. Therefore, it was suggested that the precipitation kinetics of titanium carbides in both austenite and ferrite should be investigated in future.


      PubDate: 2016-06-15T05:54:59Z
       
  • Prediction and Experimental Validation of Forming Limit Curve of a
           Quenched and Partitioned Steel
    • Abstract: Publication date: June 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 6
      Author(s): Xue-li GAO, Jun-ying MIN, Ling ZHANG, Quan-chao LI, Chang-wei LIAN, Jian-ping LIN
      Forming limit curve (FLC) is an effective tool to evaluate the formability of sheet metals. An accurate FLC prediction for a sheet metal is beneficial to its engineering application. A quenched and partitioned steel, known as QP980, is one of the 3rd generation advanced high strength steels and is composed of martensite, ferrite and a considerable amount of retained austenite (RA). Martensite transformation from RA induced by deformation, namely, transformation induced plasticity (TRIP), promotes the capability of work hardening and consequently formability. Nakazima tests were carried out to obtain the experimental forming limit strains with the aid of digital image correlation techniques. Scanning electron microscopy (SEM) was employed to examine the fracture morphologies of Nakazima specimens of the QP980 steel. The observed dimple pattern indicated that tensile stress was the predominant factor which led to failure of QP980 specimens. Therefore, maximum tensile stress criterion (MTSC) was adopted as the forming limit criterion. To predict the FLC of QP980 steel, Von-Mises yield criterion and power hardening law were adopted according to the tested mechanical properties of QP980 steel. Results were compared with those derived from other three representative instability theories, e. g. Hill criterion, Storen-Rice vertex theory and Bressan-Williams model, which shows that the MTSC based FLC is in better agreement with the experimental results.


      PubDate: 2016-06-15T05:54:59Z
       
  • Effect of Zn Vaporization on Wetting of Al-galvanized Steel in Cold Metal
           Transfer Process
    • Abstract: Publication date: June 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 6
      Author(s): Qiao-li LIN, Gao-jun MAO, Qian HUANG, Rui CAO, Jian-hong CHEN
      The wetting of galvanized steel by molten Al alloys was studied in the cold metal transfer process by the sessile drop method using a high speed video camera. The wetting behavior can be divided into two typical cases, trending of non-wetting by using small wire feeding speed and wetting by using large wire feeding speed. The Leidenfrost effect is caused by the volatilization of Zn, which is responsible for the former case. The enhanced wettability of steel by Al and the weakening of the Leidenfrost effect are responsible for the latter case. Zn is the destabilizing factor for Al-steel joining that needs to be avoided by a reasonable design of process.


      PubDate: 2016-06-15T05:54:59Z
       
  • Effects of Temperature and Alloying Elements on γ Phase Fraction of
           Grain-oriented Silicon Steel
    • Abstract: Publication date: June 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 6
      Author(s): Bing FU, Hai-jun WANG, Jian-xin YAN, Li XIANG, Sheng-tao QIU, Guo-guang CHENG
      The effects of temperature and alloying elements on γ phase fraction of grain-oriented silicon steel, which contained 2.97—3.42 mass% Si and 0.028—0.058 mass% C, were studied by microstructure observation and statistics. Furthermore, the quantitative relationships of temperature as well as C, Si, and Mn contents to γ phase fraction were obtained by numerical fitting. The experimental results show that γ phase fraction firstly increases with increasing temperature, reaches a maximum and then decreases in the temperature range of 900—1250 °C. The temperature corresponding to the maximum γ phase fraction is about 1150—1200 °C. Meanwhile, the γ phase fractions in steels at the same temperature have some differences because of different contents of various alloying elements. The verification results show that the values of γ phase fractions to C, Si, and Mn contents at the specific temperatures, which were obtained by multiple linear regression method, agree well with the measured values. In addition, the values of γ phase fractions to C, Si, and Mn contents in the temperature range of 900—1250 °C, which were obtained by binomial regression method, agree with the measured values when the contents of Mn and soluble Al are not more than 0.320 mass% and 0.034 mass%, respectively. The obtained equations can carry out the approximate prediction of γ phase fractions of grain-oriented silicon steels during the hot rolling process.


      PubDate: 2016-06-15T05:54:59Z
       
  • Effects of Nb and V on Microstructural Evolution, Precipitation Behavior
           and Tensile Properties in Hot-rolled Mo-bearing Steel
    • Abstract: Publication date: June 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 6
      Author(s): Fu-ming LIU, Jian-jun WANG, Yu-jie LIU, R.D.K. MISRA, Chun-ming LIU
      Microstructural evolution, precipitation behavior, and tensile properties of four experimental Mo-bearing steels were studied to elucidate the effects of Nb and V on microstructural properties. The results indicated that the microstructure of hot-rolled steels consisted of polygonal ferrite and degenerate pearlite, and the morphology remained same after holding at 600 °C for 1 h. The smallest grain size was obtained in Nb-V-Mo containing steel, followed by Nb-Mo and V-Mo steels. Precipitation was less in the hot-rolled Mo-bearing steel. The maximum volume fraction of precipitates was obtained in Nb-V-Mo bearing steel, and the Nb-V-Mo complex carbonitrides were highly stable at 600 °C. In the Mo-bearing steel, the yield ratio was lowest at room temperature but highest at 600 °C, which was attributed to the precipitation of Mo carbides and drag effect of Mo solute on dislocation movement.


      PubDate: 2016-06-15T05:54:59Z
       
  • Influence of Residual Stress on Shape of Heavy-gauge, High-strength Steel
           Caused by Cooling Process after Hot Rolling
    • Abstract: Publication date: June 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 6
      Author(s): Shui-ze WANG, Yong-lin KANG, Guo-ming ZHU, Wen LIANG
      The cooling process following hot rolling has a significant effect on the shape quality of a hot-rolled strip. The temperature and stress fields in the cooling process for a 14 mm thick strip with yield strength of 500 MPa grade were analyzed by the finite element method and actual test data, and the relationship between residual stress and shape defects was described. Subsequently, the small-crown rolling process and the coil slow cooling process were investigated. The results indicate that these processes improved the shape quality of the final product significantly.


      PubDate: 2016-06-15T05:54:59Z
       
  • Micro-alloying Effects of Yttrium on Recrystallization Behavior of an
           Alumina-forming Austenitic Stainless Steel
    • Abstract: Publication date: June 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 6
      Author(s): Wu-xin ZHAO, Yuan WU, Sui-he JIANG, Hui WANG, Xiong-jun LIU, Zhao-ping LU
      Micro-alloying effects of yttrium on the recrystallization behavior of an alumina-forming austenitic (AFA) stainless steel were investigated. It was found that the grain growth kinetics of the steels doped with different amounts of yttrium (i. e., 0, 0.05 and 0.10 mass% Y) could be described by an Arrhenius type empirical equation. Added Y could interact with carbon and influence the morphology of carbides both inside grains and on the grain boundaries, thus altering the grain boundary mobility and grain growth. The steel doped with 0.05 mass% yttrium showed the highest activation energy of grain growth and the most retarded recrystallization behavior, which mainly resulted from the high density of fine carbides both inside grains and on the grain boundaries. However, excess addition of 0.10 mass% Y induced coarsening and then lowered density of carbides, which alleviated the yttrium effects. The results also manifest that micro-alloying of rare-earth elements such as yttrium is an effective way for controlling grain growth behavior during recrystallization of AFA steels, which may have great implications on engineering applications.


      PubDate: 2016-06-15T05:54:59Z
       
  • Formation Mechanism of Inclusion Defects in Large Forged Pieces
    • Abstract: Publication date: June 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 6
      Author(s): Rong-sheng QI, Miao JIN, Xin-gang LIU, Bao-feng GUO
      Nonmetallic inclusions mixed into large forged metal objects destroy the continuity in the metal and affect the quality of the forged product. Research on how inclusions affect the plastic deformation of a matrix shows the significance of the formation mechanism of inclusion defects. For upset forging, the nonlinear finite element model was shown to be appropriate for the ingot hot-forging process by comparing the results with experiments involving plastic and hard inclusions inserted into the forged piece. The high-temperature stress-strain curves of MnS plastic inclusions were obtained experimentally. The results show how, during upsetting, the morphology of MnS plastic inclusions varies from spherical to ellipsoidal, until finally becoming flat in shape. The larger the inclusion is, the larger the degree of deformation of the inclusion is, and large inclusions enhance the risk of the final product failing to pass inspection for inclusion flaws. Strain significantly concentrates in the matrix near a hard inclusion. When the hard inclusion reaches a certain size, conical fractures form on both sides of the inclusion. To pass inclusion-flaw inspection and close hole defects to the extent possible, the flat-anvil upsetting is recommended. Finally, the inclusion-deformation state obtained by finite element simulation is verified experimentally.


      PubDate: 2016-06-15T05:54:59Z
       
  • Mechanism and Improvement of Straight Edge Seam Defect on Hot-rolled Plate
           Surfaces through Use of Chamfered Slabs
    • Abstract: Publication date: June 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 6
      Author(s): Hui ZHANG, Peng HU, Ming-lin WANG
      To improve the straight edge seam defect on hot-rolled steel plates, the deformation and temperature distribution of rectangular slabs and chamfered slabs during rolling in a pilot rolling experiment were analyzed in detail using the finite element method. The results showed that the crease formed on the lateral side near the edge of the plate as a result of uneven stress during broadside rolling. The creases rose to the surface with unrestricted spread and evolved into a straight edge seam during the subsequent straight rolling. To eliminate the straight edge seam defect, chamfered slabs were developed and investigated for rolling. The use of the chamfered slabs provided two advantages for rolling: the distribution of the temperature near the edge was ameliorated, and the deformation shape was improved by the chamfered shape. As a result, the risk of forming a straight edge seam defect was reduced by the use of a chamfered slab.


      PubDate: 2016-06-15T05:54:59Z
       
  • Influence of Screw Design on Burden Descending Velocity and Particle
           Segregation in COREX Shaft Furnace
    • Abstract: Publication date: June 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 6
      Author(s): Hai-feng LI, Heng ZHOU, Tao ZHANG, Yang YOU, Zong-shu ZOU, Wan-ren XU
      COREX shaft furnace (SF) is an industrial system that employs screw feeders; thus, the burden descending velocity and particle segregation in the SF can be directly affected by the design of screw. A three-dimensional actual size model of COREX-3000 SF was established using the discrete element method. Four types of burdens, including pellet, ore, flux and coke, were considered in this model. With this consideration, the effect of screw design on solid flow was investigated. Results showed that, in the base case, burdens fell primarily down from the first flight of the screw. The burden descending velocities were nearly uniform in the peripheral direction and decreased along the radial direction. In addition, the normalized particle size increased in the center area and decreased in the wall area. Reducing the flight diameter of screw benefited an even flow pattern and restrained the rolling tendency of burden from the edge to center areas. An optimized case was also proposed, in which a uniform solid flow profile could be obtained and the evenness of descending velocity along the radius could be greatly improved.


      PubDate: 2016-06-15T05:54:59Z
       
  • Stretch Bending of Z-section Stainless Steel Profile
    • Abstract: Publication date: June 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 6
      Author(s): Zheng-wei GU, Meng-meng LÜ, Xin LI, Hong XU
      The stretch bending properties of a new Z-section stainless steel profile were investigated by simulation. The causes of the forming defects, such as section distortions and poor contour precision, were analyzed, and the corresponding controlling methods were proposed. The results show that the main forming defects for the stretch bending of the Z-section profile were the flange sagging, the sidewall obliquing inward, the bottom surface up warping, and the bad contour accuracy; the cross-section distortions were mainly induced by the shrinkage of the sidewall, which could be eliminated by increasing the sidewall height of the profile reasonably; the poor contour precision was mainly due to springback, which could be controlled by modifying the die surface based on the springback amount; for the investigated bending beam, the proper sidewall height compensation was 2 mm, and the suitable die surface modification amount was 1.2 times of the springback amount, when the elongation was 10% of the initial profile length. Stretch bending tests were conducted on a new type of die with adjustable bending surfaces, and high quality components were achieved, which verified the effectiveness of the defect controlling measures.


      PubDate: 2016-06-15T05:54:59Z
       
  • Carbothermic Reduction Mechanism of Vanadium-titanium Magnetite
    • Abstract: Publication date: May 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 5
      Author(s): Shuang-yin CHEN, Xiao-jiao FU, Man-sheng CHU, Xi-zhe LI, Zheng-gen LIU, Jue TANG
      To achieve the high-efficiency utilization of vanadium-titanium magnetite (VTM), reduction experiments were conducted to determine the carbothermic reduction mechanism of VTM. Effects of volatile matter, temperature, time, and carbon ratio (molar ratio of fixed carbon in coal to oxygen in iron oxides of VTM) on reduction degree were investigated. Results show that reduction degree increases with increasing volatile matter in coal, temperature, time, and carbon ratio. Phase transformation, microstructure, and reduction path were analyzed by X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and FactSage 6.0. The thermoravimetry-differential scanning calorimetry-quadrupole mass spectrometer method was used for kinetic analysis of the main reduction process. Results indicate that the kinetic mechanism follows the principle of random nucleation and growth (n=4), and the activation energy values at 600–900 and 900–1350 °C are 88.7 and 295.5 kJ/mol, respectively.


      PubDate: 2016-05-16T18:27:34Z
       
 
 
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