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ENVIRONMENTAL STUDIES (754 journals)            First | 1 2 3 4     

Showing 601 - 378 of 378 Journals sorted alphabetically
Political Studies Review     Hybrid Journal   (Followers: 15)
Population and Environment     Hybrid Journal   (Followers: 5)
Population Ecology     Hybrid Journal   (Followers: 10)
Population Studies: A Journal of Demography     Hybrid Journal   (Followers: 9)
Postcolonial Studies     Hybrid Journal   (Followers: 10)
Practice Periodical of Hazardous, Toxic, and Radioactive Waste Management     Full-text available via subscription   (Followers: 2)
Presence Teleoperators & Virtual Environments     Hybrid Journal   (Followers: 1)
Present Environment and Sustainable Development     Open Access  
Presidential Studies Quarterly     Hybrid Journal   (Followers: 3)
Procedia Environmental Sciences     Open Access  
Proceedings of the Institution of Civil Engineers - Waste and Resource Management     Hybrid Journal   (Followers: 2)
Proceedings of the Institution of Mechanical Engineers Part M: Journal of Engineering for the Maritime Environment     Hybrid Journal   (Followers: 2)
Proceedings of the International Academy of Ecology and Environmental Sciences     Open Access   (Followers: 3)
Process Safety and Environmental Protection     Hybrid Journal   (Followers: 5)
Progress in Industrial Ecology, An International Journal     Hybrid Journal   (Followers: 4)
Przegląd Prawa Ochrony Środowiska     Open Access  
Psychological Assessment     Full-text available via subscription   (Followers: 7)
Public Money & Management     Hybrid Journal   (Followers: 9)
Public Works Management & Policy     Hybrid Journal   (Followers: 7)
Qatar Foundation Annual Research Forum Proceedings     Open Access   (Followers: 3)
Radioactivity in the Environment     Full-text available via subscription   (Followers: 4)
Regional Environmental Change     Hybrid Journal   (Followers: 3)
Regional Studies     Hybrid Journal   (Followers: 8)
Religious Studies     Hybrid Journal   (Followers: 11)
Remediation Journal     Hybrid Journal   (Followers: 5)
Remote Sensing Letters     Hybrid Journal   (Followers: 14)
Renaissance Studies     Hybrid Journal   (Followers: 15)
Rendiconti Lincei     Hybrid Journal  
Renewable Energy Focus     Full-text available via subscription   (Followers: 8)
Research & Reviews : Journal of Ecology     Full-text available via subscription   (Followers: 1)
Research and Practice for Persons with Severe Disabilities     Full-text available via subscription   (Followers: 4)
Research Journal of Environmental Sciences     Open Access   (Followers: 2)
Research Journal of Environmental Toxicology     Open Access   (Followers: 2)
ReSource     Full-text available via subscription  
Resources     Open Access  
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Resources, Conservation and Recycling     Hybrid Journal   (Followers: 25)
Reuse/Recycle Newsletter     Hybrid Journal   (Followers: 1)
Review of English Studies     Hybrid Journal   (Followers: 6)
Review of Environmental Economics and Policy     Hybrid Journal   (Followers: 7)
Revista AIDIS de Ingeniería y Ciencias Ambientales. Investigación, desarrollo y práctica     Open Access  
Revista Ambivalências     Open Access  
Revista Brasileira de Engenharia Agrícola e Ambiental     Open Access   (Followers: 1)
Revista Capital Científico     Open Access  
Revista Chapingo. Serie Ciencias Forestales y del Ambiente     Open Access  
Revista de Ciências Ambientais     Open Access  
Revista de Ciencias Ambientales     Open Access  
Revista de Gestão Ambiental e Sustentabilidade - GeAS     Open Access  
Revista de Salud Ambiental     Open Access  
Revista Eletrônica de Gestão e Tecnologias Ambientais     Open Access  
Revista Eletrônica em Gestão, Educação e Tecnologia Ambiental     Open Access  
Revista Eletrônica TECCEN     Open Access  
Revista Hábitat Sustenable     Open Access   (Followers: 1)
Revista Internacional de Ciências     Open Access  
Revista Meio Ambiente e Sustentabilidade     Open Access  
Revista Monografias Ambientais     Open Access  
Revista Verde de Agroecologia e Desenvolvimento Sustentável     Open Access   (Followers: 2)
Ring     Open Access   (Followers: 1)
Riparian Ecology and Conservation     Open Access   (Followers: 5)
Rivista di Studi sulla Sostenibilità     Full-text available via subscription  
Russian Journal of Ecology     Hybrid Journal   (Followers: 1)
S.A.P.I.EN.S     Open Access   (Followers: 2)
Safety Science     Hybrid Journal   (Followers: 16)
San Francisco Estuary and Watershed Science     Open Access   (Followers: 1)
SAR and QSAR in Environmental Research     Hybrid Journal  
Scandinavian Journal of Work, Environment & Health     Partially Free   (Followers: 12)
Scandinavian Political Studies     Hybrid Journal   (Followers: 6)
Science of The Total Environment     Hybrid Journal   (Followers: 16)
Sciences Eaux & Territoires : la Revue du Cemagref     Open Access  
Scientific Journal of Environmental Sciences     Open Access   (Followers: 1)
Scientific Studies of Reading     Hybrid Journal   (Followers: 3)
Sepsis     Hybrid Journal  
Slavery & Abolition: A Journal of Slave and Post-Slave Studies     Hybrid Journal   (Followers: 7)
Smart Grid and Renewable Energy     Open Access   (Followers: 8)
Social & Legal Studies     Hybrid Journal   (Followers: 11)
Social and Environmental Accountability Journal     Hybrid Journal   (Followers: 2)
Social Studies of Science     Hybrid Journal   (Followers: 21)
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: 5)
Stochastic Environmental Research and Risk Assessment     Hybrid Journal   (Followers: 2)
Strategic Planning for Energy and the Environment     Hybrid Journal   (Followers: 4)
Studies in Christian Ethics     Hybrid Journal   (Followers: 7)
Studies in Conservation     Hybrid Journal   (Followers: 9)
Studies in Environmental Science     Full-text available via subscription   (Followers: 6)
Studies in Interreligious Dialogue     Full-text available via subscription   (Followers: 2)
Studies in Spirituality     Full-text available via subscription   (Followers: 7)
Sustainability     Open Access   (Followers: 17)
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 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  
Tertiary Education and Management     Hybrid Journal   (Followers: 7)
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: 15)
Toxicological & Environmental Chemistry     Hybrid Journal   (Followers: 4)
Toxicological Sciences     Hybrid Journal   (Followers: 9)
Toxicology     Hybrid Journal   (Followers: 17)
Toxicology and Applied Pharmacology     Hybrid Journal   (Followers: 16)
Toxicology and Industrial Health     Hybrid Journal   (Followers: 7)
Toxicology in Vitro     Hybrid Journal   (Followers: 11)
Toxicology Letters     Hybrid Journal   (Followers: 12)
Toxicology Mechanisms and Methods     Hybrid Journal   (Followers: 9)
Toxicon     Hybrid Journal   (Followers: 2)
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)
Transition Studies Review     Hybrid Journal  
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: 154)
Trends in Environmental Analytical Chemistry     Hybrid Journal   (Followers: 2)
Trends in Pharmacological Sciences     Full-text available via subscription   (Followers: 26)
Turkish Journal of Engineering and Environmental Sciences     Open Access   (Followers: 1)
UCLA Journal of Environmental Law and Policy     Open Access   (Followers: 4)
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: 2)
Villanova Environmental Law Journal     Open Access  
Visitor Studies     Hybrid Journal   (Followers: 6)
Waste Management & Research     Hybrid Journal   (Followers: 10)
Water Environment Research     Full-text available via subscription   (Followers: 35)
Water International     Hybrid Journal   (Followers: 10)
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: 8)
Weather, Climate, and Society     Full-text available via subscription   (Followers: 8)
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)
Worldviews: Global Religions, Culture, and Ecology     Hybrid Journal   (Followers: 8)
Zoology and Ecology     Hybrid Journal   (Followers: 3)
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]   [7 followers]  Follow
   Full-text available via subscription Subscription journal
   ISSN (Print) 1006-706X
   Published by Elsevier Homepage  [2970 journals]
  • Phase Transformation of a Cold Work Tool Steel during Tempering
    • Abstract: Publication date: May 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 5
      Author(s): Hong-xiao CHI, Dang-shen MA, Hui-xia XU, Wang-long ZHU, Jian-qing JIANG
      The hardness and microstructure evolution of a 8% Cr cold work tool steel during tempering for 40 h were investigated. Transmission electron microscope examinations showed that M3C carbides precipitated from supersaturated martensite after tempering at 350 °C. When the tempering temperature was higher than 520 °C, the M23C6 carbides precipitated to substitute for M3C carbides. After ageing at the temperature of 520 °C for 40 h, it was observed that very fine and dense secondary Mo2C precipitates were precipitated. Thus, it can be concluded that the early stage of Mo2 C-carbidc precipitation is like to be Gunier–Preston (G–P) zone formed by [Mo-C] segregation group which is responsible for the secondary hardening peak at 520 °C. Overageing at 700 °C resulted in recovery of martensitic microstructure and precipitation of M23C6 carbides. When ageing at 700 °C for more than 20 h, recrystallization occurred, which resulted in a change of the matrix morphology from martensitic plates to equiaxed ferrite. It was noticed that the size of recrystallized grain/subgrain was very fine, which was attributed to the pinning effect of M23C6 precipitates.

      PubDate: 2016-05-16T18:27:34Z
  • Influence of Vanadium on Fracture Splitting Property of Medium Carbon
    • Abstract: Publication date: May 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 5
      Author(s): Wei-jun HUI, Cheng-wei SHAO, Yong-jian ZHANG, Si-lian CHEN, Han DONG
      The fracture splitting property of medium carbon steel 37MnSiS microalloyed with V up to 0. 45% was investigated by using simulated fracture splitting test, for the development of new crackable medium carbon steel to manufacture high performance connecting rod. Conventional high carbon steel C70S6 was used for comparison. The results show that the volume fraction of both ferrite and V-rich M(C, N) particles increases, and the pearlite interla-mellar spacing decreases with increasing V content, which in turn results in gradual increase of strength and decrease of ductility and impact energy. The fracture splitting property of the tested steel could be improved significantly due to the increase of V content mainly through the precipitation hardening mechanism of fine M(C, N) precipitates. The fraction of brittle cleavage fracture in the crack initiation area increases noticeably with increasing V content and full brittle cleavage fracture surface could be obtained when V content was increased to 0. 45%. It is concluded that medium carbon steel with V content higher than about 0. 28% possesses not only comparable or even higher mechanical properties with those of conventional steel C70S6, but also excellent fracture splitting property, and therefore, is more suitable to fabricate high performance fracture splitting connecting rod.

      PubDate: 2016-05-16T18:27:34Z
  • Static Recrystallization Behavior of SA508-III Steel during Hot
    • Abstract: Publication date: May 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 5
      Author(s): Ding-qian DONG, Fei CHEN, Zhen-shan CUI
      The static recrystallization behavior of SA508-III steel was investigated by isothermal double-hit hot compression tests at the deformation temperature of 950–1250 °C, the strain rate of 0. 01–1 s−1, and the inter-pass time of 1–300 s. The effects of deformation parameters, including forming temperature, strain rate, degree of deformation (pre-strain) and initial austenite grain size, on the softening kinetics were analyzed. Experimental results show that static recrystallization kinetics is strongly dependent on deformation temperature and degree of deformation, while less affected by the strain rate and initial grain size. The kinetics and microstructural evolution equations of static recrystallization for SA508-III steel were developed to predict the softening behavior and the statically recrystallized grain size, respectively. Based on the comparison between the experimental and predicted results, it is found that the established equations can give a reasonable estimate of the static softening behavior for SA508-III steel.

      PubDate: 2016-05-16T18:27:34Z
  • Effect of Spark Plasma Sintering Temperature on Electrochemical Properties
           of La0.82Mg0.18Ni3.50Co0.15 Alloy
    • Abstract: Publication date: May 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 5
      Author(s): Xiao-ping DONG, Yan-rong PANG, Li-ying YANG, Qing WANG, Zhi-yuan LI
      Electrochemical properties of La0.82 Mg0.18 Ni3.50 Co0.15 alloys synthesized by spark plasma sintering (SPS) were investigated based on the electrochemical measurements, physical parameters and microstructure observation. The sintering behavior of La0.82 Mg0.18 Ni3.50 Co0.13 alloys at the temperatures of 900, 950 and 1000 °C is characterized by four stages, i.e., initial slight shrinkage, expansion, abrupt shrinkage and slight expansion. The maximum shrinkage displacement increases with increasing sintering temperature. All of the alloys consist of (La, Mg)2 (Ni, Co)7 phase; additionally, temperatures of 900 and 950 °C are beneficial to the formation of (La, Mg) (Ni, Co)3 phase, whereas the LaNi5 phase is easy to form in the alloy synthesized by SPS at 1000 °C. The electrochemical measurements indicate an evident change of the electrochemical performance of the alloys associated with increasing the sintering temperature. The discharge capacity of the alloys first increases and then decreases as sintering temperature rises, whereas their cycle stability clearly grows all the time. Furthermore, the charging-discharging potential difference and discharging efficiency both demonstrate that the electrochemical properties of the alloy electrodes first augment and then decline with increasing sintering temperature.

      PubDate: 2016-05-16T18:27:34Z
  • Evolution of Microstructure and Ordering in Rolling Process of Fe-6. 5
           mass% Si Alloy
    • Abstract: Publication date: May 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 5
      Author(s): Hui LI, Yong-feng LIANG, Feng YE
      Fe-6. 5 mass% Si alloy is an excellent soft magnetic material with good application prospects. After rolling, the structure of the sheet is likely to be heterogeneous along the normal direction. The microstructure and ordering evolution in the thickness range of the sheets during hot-warm rolling process was studied by means of optical microscope and transmission electron microscope. The results show that dynamic recrystallization occurs in the surface parts during the hot and warm rolling processes, where the grains are equiaxed but have high density of dislocations due to the large deformation. The grains in the center part are elongated along the rolling direction. It is also found that in the hot rolled sheet, the center part has lower density of dislocations because of dynamic recovery. Meanwhile, this part has higher ordering content compared with the surface part, indicating that the high density of dislocations can inhibit the formation of ordering in the air cooling process after hot rolling. In the warm rolling process, both of the parts are deformed heavily. Large deformation destroys ordered phases and induces disordering. The ordering content is low in the whole warm rolled sheet.

      PubDate: 2016-05-16T18:27:34Z
  • Deformation Behavior of Fe-36Ni Steel during Cryogenic (123–173 K)
    • Abstract: Publication date: May 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 5
      Author(s): Jian-jun ZHENG, Chang-sheng LI, Shuai HE, Ban CAI, Yan-lei SONG
      Microstructural evolution and mechanical properties of cryogenic rolled Fe-36Ni steel were investigated. The annealed Fe-36Ni steel was rolled at cryogenic temperature (123–173 K) with 20%–90% rolling reduction in thickness. The deformation process was accompanied by twinning at cryogenic temperature, and the mean thickness of deformation twins was about 200 nm with 20% rolling reduction. When the rolling reduction was above 40%, twinning was suppressed due to the stress concentration in the tested steel. Deformation microstructure of Fe-36Ni steel consisted of both twin boundaries and dislocations by cryogenic rolling (CR), while it only contained dislocations after rolling at room temperature (RT). The tensile strength of Fe-36Ni steel was improved to 930 MPa after 90% reduction at cryogenic temperature, while the tensile strength after 90% reduction at RT was only 760 MPa. More dislocations could be produced as the nucleation sites of recrystallization during CR process.

      PubDate: 2016-05-16T18:27:34Z
  • In-situ TEM Observation of Cementite Coarsening Behavior of 5Mn Steel
           during Tempering
    • Abstract: Publication date: May 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 5
      Author(s): Ye XIA, Xi-nan LUO, Xiao-yan ZHONG, Hui-hua ZHOU, Cun-yu WANG, Jie SHI
      The cementite formation and coarsening behaviors of 0. 2 mass% C-5 mass% Mn steel during tempering at 500 °C were investigated by in-situ transmission electron microscope (TEM). In-situ TEM observation showed uniform distribution of cementite particles at the early stage of tempering in the rapidly heated (500 °C/s) sample. Elemental analysis confirmed that the cementite growth was dominated by Mn diffusion. During the cementite growth, the coarsening behavior of intragranular cementite was significantly controlled by the matrix diffusion, while that of the intergranular cementite was mainly governed by the boundary diffusion. The in-situ TEM observation revealed that the dislocation pipe diffusion of Mn took place during tempering, which accelerated the Mn diffusion between cementite particles. The coarsening rates of individual cementite particles were calculated based on the in-situ TEM observation.

      PubDate: 2016-05-16T18:27:34Z
  • Intelligent Control of Grate-kiln-cooler Process of Iron Ore Pellets Using
           a Combination of Expert System Approach and Takagi-Sugeno Fuzzy Model
    • Abstract: Publication date: May 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 5
      Author(s): Gui-ming YANG, Xiao-hui FAN, Xu-ling CHEN, Xiao-xian HUANG, Zong-ping LI
      Grate-kiln-cooler has become a major process of producing iron ore pellets in China. Due to the diversity of the raw materials used and the multi-device multi-variable characteristics, this process still encounters with control problem. An attempt was proposed to deal with this issue. The three-device-integrated feature of the process was firstly analyzed to obtain control strategy, and then an intelligent control system using a combination of expert system approach and Takagi-Sugeno (T-S) fuzzy model was developed. Expert system approach was used to diagnose and remedy the abnormal conditions, while T-S fuzzy model was used to stabilize the thermal state. In the construction of T-S fuzzy rules, antecedents were identified by fuzzy c-mean clustering algorithm incorporated with subtractive clustering algorithm, and consequent parameters were identified by recursive least square algorithm. The control system was applied in a Chinese pelletizing plant and the application results demonstrated its effectiveness of stabilizing the thermal states within three devices.

      PubDate: 2016-05-16T18:27:34Z
  • Effect of Sodium Sulfate on Direct Reduction of Beach Titanomagnetite for
           Separation of Iron and Titanium
    • Abstract: Publication date: May 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 5
      Author(s): En-xia GAO, Ti-chang SUN, Zhi-guo LIU, Chao GENG, Cheng-yan XU
      The effect of sodium sulfate on direct reduction of beach titanomagnetite, followed by magnetic separation, to separate iron and titanium was investigated. Direct reduced iron (DRI) with a high Fe content, low TiO2 content and low iron recovery was obtained after adding sodium sulfate. When the sodium sulfate dosage was increased from 0 to 10 mass %, the Fe content of the DRI increased from 90. 00 mass% to 93. 55 mass% and the TiO2 content decreased from 1. 27 mass% to 0. 70 mass%. The reduction mechanism of sodium sulfate was investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM) with energy dispersive spectrometer (EDS). Results revealed that the metallic iron grains in the reduced ore with sodium sulfate were larger than those in the ore without sodium sulfate. Sodium sulfate promoted the migration of iron as well as the accumulation and growth of metallic iron grains by low-melting-point carnegieite and troilite formed in the redox system. Low-melting-point carnegieite decreased the melting point of the system and then promoted liquefaction. Troilite could decrease the surface tension and melting point of metallic iron grains.

      PubDate: 2016-05-16T18:27:34Z
  • An Experimental Prototype of an Innovative Fluid-driven Electromagnetic
           Stirring Technique
    • Abstract: Publication date: May 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 5
      Author(s): Bo WANG, Xiao-dong WANG, Yuri KOLESNIKOV, San ZHANG, Yan-qing TAN, Xian-zhao NA
      A new electromagnetic stirring technique that is driven by hydrodynamic forces was presented. This technique offers the following advantages. First, the stirrer can be immersed in the liquid metal, thereby significantly increasing the penetration depth of the electromagnetic forces and significantly improving the stirring efficiency; thus, this technique is particularly suitable for large-scale liquid metal. Second, under certain conditions, this technique can overcome difficulties that are encountered with traditional stirrers, such as accessing regions that are difficult to reach in working spaces with complex or narrow shapes. This stirrer also has a simpler structure than a traditional stirrer; thus, the design can be easily modified, and no external power supply is required. An experimental prototype was also presented for controlling the fluid flow rate, thereby controlling the electromagnetic force and velocity field of the driven liquid metal. The velocity distribution in a liquid GaInSn alloy under fluid-driven electromagnetic stirring was quantitatively measured using ultrasonic Doppler velocimetry (UDV). The primary results show that a remarkable velocity field has been achieved and that fluid-driven electromagnetic stirring is an effective means of stirring liquid metal. Finally, the potential applications of this technique in industry, along with key challenges, were discussed.

      PubDate: 2016-05-16T18:27:34Z
  • 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
  • Effect of Mg Addition on Nucleation of Intra-granular Acicular Ferrite in
           Al-killed Low Carbon Steel
    • Abstract: Publication date: May 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 5
      Author(s): Xiao-bing LI, Yi MIN, Zhe YU, Cheng-jun LIU, Mao-fa JIANG
      To verify the formation behaviors and mechanisms of intra-granular acicular ferrite (IAF) grains nucleated by Mg-Al-O in low carbon steel, the steels containing different Mg contents were refined in a vacuum induction furnace. The effect of Mg addition on the formation of IAF structure in Al-killed low carbon steel was investigated by optical microscope (OM) and scanning electron microscope with energy dispersive X-ray spectroscope (SEM-EDX). It reveals that the IAFs are only detected in Mg-added steels, and the volume fraction of IAF increases with the Mg concentration from 8×10−6 to 26×10−6. It shows that not only the MgO-Al2O3-MnS and MgO-Al2O3-P2O3 particles are the effective nucleation sites for IAF, but also the pure MgO · Al2O3 phase can promote the ferrite nucleation. A Mn-depletion zone (MDZ) is characterized adjacent to the MgO-Al2 O3-MnS, which is believed to be one of the possible mechanisms to explain the IAF nucleation. The MDZ around the MgO-Al2 O3-MnS inclusion would be induced by the MnS precipitation on the inclusion. It seems that the ability of Mg-containing inclusions to induce the nucleation of ferrite might be attributed to a new mechanism, i. e., the P-rich zone formed on a few Mg-Al-O inclusions might be another factor for promoting the IAF formation.

      PubDate: 2016-05-16T18:27:34Z
  • Micromechanical Behavior and Failure Mechanism of F/B Multi-phase High
           Performance Steel
    • Abstract: Publication date: May 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 5
      Author(s): Cun-jiang TANG, Shi-long LIU, Cheng-jia SHANG
      The deformation and micro-voids formation mechanisms in ferrite/bainite (F/B) multi-phase steel with the volume fraction of bainite less than 50% were studied by numerical simulation and experimental observation. The results show that the micro-strain concentrates at the soft/hard phase (F/B) interface in the multi-phase steel, which should be correlated with the mechanism of incoordinate deformation. During the necking of the steel, the micro-voids initially form around the F/B interface, which also form in ferrite and bainite with the severe strain. The micro-voids in bainite are more dense and finer than those in ferrite. The failure mechanism of bainite is the coalescence of micro-voids, and the failure mechanism of ferrite is the growth and tearing of micro-voids. Due to the different failure mechanisms of ferrite and bainite, a suitable part of soft phase would be beneficial to the capability of anti-failure of F/B multi-phase steel during the ductile fracture.

      PubDate: 2016-05-16T18:27:34Z
  • Characterization of (Nb,Ti,Mo)C Precipitates in an Ultrahigh Strength
           Martensitic Steel
    • Abstract: Publication date: May 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 5
      Author(s): Biao JU, Hui-bin WU, Di TANG, Ning DANG
      A study on ultrahigh strength steel plate subjected to novel thermo-mechanical control process was presented. The mechanical properties examination showed that the investigated steel exhibited excellent combination of ultra-high strength (2200 MPa) and toughness (26 J). The microstructure of the experimental steel was observed by scanning electron microscope and transmission electron microscope. Desired martensitic lath with width of about 180–230 nm was obtained. Nanostructured carbide precipitates with sizes of 20–50 nm, which contained Nb, Ti and Mo, were observed in the lath martensitic microstructure, and confirmed to be MC-type carbides with B1 structure by means of selected area electron diffraction. The compositional characteristics revealed by energy dispersive X-ray spectrometer mapping implied that the carbide forming elements Nb, Ti and Mo distributed in the precipitates evenly. Three-dimensional atom probe tomography reconstruction further indicated that Mo incorporated into the precipitates without enrichment in the carbide-matrix interface and probably substituted for Nb and Ti to form the (Nb,Ti,Mo)C carbides.

      PubDate: 2016-05-16T18:27:34Z
  • Hot Deformation Behavior and Processing Map of Spray Formed M3: 2 High
           Speed Steel
    • Abstract: Publication date: May 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 5
      Author(s): Lin LU, Long-gang HOU, Hua CUI, Jin-feng HUANG, Yong-an ZHANG, Ji-shan ZHANG
      Hot deformation behavior of a new type of M3 : 2 high speed steel with niobium addition made by spray forming was investigated based on compression tests in the temperature range of 950–1150 °C and strain rate of 0.001–10s−1. A comprehensive constitutive equation was obtained, which could be used to predict the flow stress at different strains. Processing map was developed on the basis of the flow stress data using the principles of dynamic material model. The results showed that the flow curves were in fair agreement with the dynamic recrystallization model. The flow stresses, which were calculated by the comprehensive constitutive equation, agreed well with the test data at low strain rates (≤1 s−1). The material constant (α), stress exponent (n) and the hot deformation activation energy (Q HW) of the new steel were 0. 00615 MPa−1, 4.81 and 546 kJ ·mol−1, respectively. Analysis of the processing map with an observation of microstructures revealed that hot working processes of the steel could be carried out safely in the domain (T=1050–1150 °C, ɛ = 0.01–0.1 s−1) with about 33% peak efficiency of power dissipation (η). Cracks was expected in two domains at either lower temperatures (<1000 °C) or low strain rates (0.001 s−1) with different cracking mechanisms. Flow localization occurred when the strain rates exceeded 1 s−1 at all testing temperatures.

      PubDate: 2016-05-16T18:27:34Z
  • Surface Modification by Nitrogen Plasma Immersion Ion Implantation on
           Austenitic AISI 304 Stainless Steel
    • Abstract: Publication date: April 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 4
      Author(s): Miguel CASTRO-COLIN, William DURRER, Jorge A. LÓPEZ, Enrique RAMIREZ-HOMS
      Surfaces of AISI 304 austenitic stainless steel plates nitrided by plasma immersion ion implantation (PIII) technology were studied by means of Auger electron spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS) to determine the effect of the nitriding process on the surface and subjacent layers. Elemental compositions obtained by AES and XPS at varying depths indicate that the saturation of N is relatively constant as a function of depth, indicating the reliability of PIII technology for subsurface saturation. It is concluded that the concentrations of both Cr and O increase with depth, the subjacent oxide is driven by the Ar+ sputtering process used to access the lower layers, and then N is bound to Cr.

      PubDate: 2016-05-05T10:35:22Z
  • Microstructure Evolution and Precipitation Behavior of 0Cr16Ni5Mo
           Martensitic Stainless Steel during Tempering Process
    • Abstract: Publication date: April 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 4
      Author(s): Wu-hua YUAN, Xue-hui GONG, Yong-qing SUN, Jian-xiong LIANG
      The microstructure, morphology of precipitates and retained austenite and the volume fraction of retained austenite in 0Cr16Ni5Mo stainless steel during the tempering process were analyzed using optical microscope (OM), transmission electron microscope (TEM), X-ray diffraction (XRD) and scanning transmission electron microscope (STEM). The results show that the microstructure of the tempered steel is mainly composed of tempered martensite, retained austenite, and delta ferrite. In the case of samples tempered from 500 to 700 °C, the precipitates are mainly M23 C6, which precipitate along the lath martensite boundaries. The precipitate content increases with the tempering temperature. During the tempering process, the content of retained austenite initially increases and then decreases, the maximum content of retained austenite being 29 vol. % upon tempering at 600 °C. TEM analysis of the tested steel reveals two morphology types of retained austenite. One is thin film-like retained austenite that exists along the martensite lath boundary. The other is blocky austenite located on packet at the boundary and the original austenite grain boundary. To further understand the stability of reversed austenite, the Ni content in reversed austenite was measured using STEM. Results show a significant difference in nickel concentrations between reversed austenite and martensite.

      PubDate: 2016-05-05T10:35:22Z
  • Effects of Solution Depletion and Segregation Oxidation on Morphology of
           Modified 310 Austenitic Stainless Steel
    • Abstract: Publication date: April 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 4
      Author(s): Hong-ying SUN, Qiang HE, Zhang-jian ZHOU, Man WANG, Guang-ming ZHANG, Shao-fu LI
      The oxidation morphologies of modified 310 steel exposed in 900 and 1100 °C air were investigated. A double layer morphology consisting of a (Cr, Mn)-rich outer layer and a fine Cr-rich inner layer was formed at 900 °C. It was related to the breakaway oxidation induced by the Cr-depletion and the Mn-segregation in inner layer. Some Cr-rich oxides with amorphous state were formed along grain boundaries. And some new finer oxide grains, voids and Cr-rich precipitates were observed in spallation areas at 1100 °C. Correspondingly, the oxidation kinetic curve dropped with the spallation of scale and increased with the formation of some new oxide grains. It was caused by segregation of Cr and the transformation of oxides from Cr2 O3 to the volatile oxides at elevated temperature. XRD analysis showed that the precipitates were mainly composed of CrO3. Segregation and depletion for solutions were also discussed by oxidation diffusion mechanisms.

      PubDate: 2016-05-05T10:35:22Z
  • Strain-induced Precipitation in Ti Micro-alloyed Interstitial-free Steel
    • Abstract: Publication date: April 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 4
      Author(s): Ya-jun HUI, Yang YU, Lin WANG, Chang WANG, Wen-yuan LI, Bin CHEN
      Stress relaxation method was carried out on a Ti micro-alloyed interstitial-free (IF) steel at the temperature ranging from 800 to 1000 °C. The results show that the softening kinetics curves of deformed austenite can be divided into three stages. At the first stage, the stress has a sharp drop due to the onset of recrystallization. At the second stage, a plateau appears on the relaxation curves indicating the start and finish of strain-induced precipitation. At the third stage, the stress curves begin to descend again because of coarsening of precipitates. Precipitation-time-temperature (PTT) diagram exhibited a “C” shape, and the nose point of the PTT diagram is located at 900 °C and the start precipitation time of 10 s. The theoretical calculation shows that the strain-induced precipitates were confirmed as almost pure TiC particles. The TiC precipitates were heterogeneously distributed in either a chain-like or cell-like manner observed by transmission electron microscopy (TEM), which indicates the precipitates nucleated on dislocations or dislocation substructures. In addition, a thermodynamic analytical model was presented to describe the precipitation in Ti micro-alloyed IF steel, which shows a good agreement between the experimental observation and the predictions of the model.

      PubDate: 2016-05-05T10:35:22Z
  • A Flow Stress Model for High Strength Steels with Low Carbon Bainite
    • Abstract: Publication date: April 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 4
      Author(s): Bao-sheng XIE, Qing-wu CAI, Wei YU, Shi-xin XU, Ban WANG
      Two kinds of steels (YP960 and YP690) with low carbon bainite structure were designed, and their flow stress and strain hardening exponents were studied. The results showed that, when Hollomon relation was applied to describe the flow stress, there were significant errors between the experimental and calculated points in specimens tempered below 400 °C, while a high precision was observed in samples tempered above 400 °C. Whereas, the modified Voce relation could effectively predict the flow stress as well as the strain hardening exponent at different tempering temperatures, which was verified by unbiased estimators such as maximum relative error (MRXE) and average absolute relative error (AARE). Besides, the modified Voce relation was also applied to estimate the maximum uniform strain, and the correlation coefficients (R) between the experimental data and calculated maximum uniform strain were more than 0. 91. The high correlation coefficients indicated that the modified Voce relation could effectively predict the uniform deformation ability of high strength steels with low carbon bainite structure at different tempering temperatures.

      PubDate: 2016-05-05T10:35:22Z
  • A Physically Based Dynamic Recrystallization Model Considering Orientation
           Effects for a Nitrogen Alloyed Ultralow Carbon Stainless Steel during Hot
    • Abstract: Publication date: April 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 4
      Author(s): Gan-lin XIE, An HE, Hai-long ZHANG, Gen-qi WANG, Xi-tao WANG
      The nitrogen alloyed ultralow carbon stainless steel is a good candidate material for primary loop pipes of AP1000 nuclear power plant. These pipes are manufactured by hot forging, during which dynamic recrystallization acts as the most important microstructural evolution mechanism. A physically based model was proposed to describe and predict the microstructural evolution in the hot forging process of those pipes. In this model, the coupled effects of dislocation density change, dynamic recovery, dynamic recrystallization and grain orientation function were considered. Besides, physically based simulation experiments were conducted on a Gleeble-3500 thermo-mechanical simulator, and the specimens after deformation were observed by optical metallography (OM) and electron back-scattered diffraction (EBSD) method. The results confirm that dynamic recrystallization is easy to occur with increasing deformation temperature or strain rate. The grains become much finer after full dynamic recrystallization. The model shows a good agreement with experimental results obtained by OM and EBSD in terms of stress-strain curves, grain size, and recrystallization kinetics. Besides, this model obtains an acceptable accuracy and a wide applying scope for engineering calculation.

      PubDate: 2016-05-05T10:35:22Z
  • Effect of Solution Annealing Temperature on Pitting Behavior of Duplex
           Stainless Steel 2204 in Chloride Solutions
    • Abstract: Publication date: April 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 4
      Author(s): Liang HE, Yan-jun GUO, Xia-yu WU, Yi-ming JIANG, Jin LI
      The effect of solution annealing temperature ranging from 950 to 1200 °C on the microstructure and corrosion performance of duplex stainless steel (DSS) 2204 were investigated. The proportion of the ferrite phase increased while the austenite phase decreased and the ferrite stabilizing elements diluted in the ferrite phase with the increase of annealing temperature. The critical pitting temperature (CPT) of specimens annealed at 1000 °C was higher than those annealed at 950 °C, whereas further increasing the annealing temperature to 1200 °C decreased the CPT. The pitting initiation sites were observed in the austenite phase, at the boundary of ferrite/austenite phase and inside the ferrite phase for specimens annealed at 950, 1000 °C and exceeding 1100 °C, respectively. The evolution trend of the CPT and the pit initiation site were analyzed by the pitting resistance equivalent number.

      PubDate: 2016-05-05T10:35:22Z
  • Strengthening Mechanisms for Ti- and Nb-Ti-micro-alloyed High-strength
    • Abstract: Publication date: April 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 4
      Author(s): Chuan-feng MENG, Yi-de WANG, Ying-hui WEI, Bin-qing SHI, Tian-xie CUI, Yu-tian WANG
      The strengthening mechanisms of hot-rolled steels micro-alloyed with Ti (ST-TQ500) and Nb-Ti (NT-TQ500) were investigated by examining the microstructures of steels using optical microscope (OM), scanning electron microscope (SEM) and transmission electron microscope (TEM). The results revealed almost no differences in the solute solution strengthening and fine-grained strengthening of the two steels, whereas the contributions of precipitation strengthening and dislocation strengthening were different for ST-TQ500 and NT-TQ500. The measured precipitation strengthening effect of ST-TQ500 was 88 MPa higher than that of NT-TQ500; this difference was primarily attributed to the stronger precipitation effect of the Ti-containing nanoscale particles. The dislocation strengthening effect of ST-TQ500 was approximately 80 MPa lower than that of NT-TQ500. This is thought to be related to differences in deformation behavior during the finishing rolling stage; the inhibition of dynamic recrystallization from Nb in NT-TQ500 (Nb-Ti) may lead to higher density of dislocations in the microstructure.

      PubDate: 2016-05-05T10:35:22Z
  • Effect of Deformation Temperature on Deformation Mechanism of Fe-6. 5Si
           Alloys with Different Initial Microstructures
    • Abstract: Publication date: April 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 4
      Author(s): Hua-dong FU, Yuan-ke MO, Long-chao ZHUO, Zhi-hao ZHANG, Jian-xin XIE
      Deformation behaviors and mechanisms under different temperatures for columnar-grained Fe-6. 5Si (mass%) alloys fabricated by directional solidification and equiaxed-grained Fe-6. 5Si alloy fabricated by forging were comparatively investigated. The results showed that, with increasing the deformation temperature from 300 °C to 500 °C, the elongation increased from 2. 9% to 30. 1% for the equiaxed-grained Fe-6. 5Si alloy, while from 6. 6% to about 51 % for the columnar-grained Fe-6. 5Si alloy. The deformation mode of equiaxed-grained Fe-6. 5Si alloy transferred from nearly negligible plastic deformation to large plastic deformation dominated by dislocation slipping. Comparatively, the deformation mode of the columnar-grained alloy transferred from nearly negligible plastic deformation to plastic deformation dominated by the twining, and finally to plastic deformation dominated by dislocation slipping. Meanwhile, compared with the alloy with equiaxed grains, it was found that ultimate tensile strength and elongation could be increased simultaneously, which was ascribed for the twinning deformation in columnar-grained Fe-6. 5Si alloy. This work would assist us to further understand the plastic deformation mechanism of Fe-6. 5Si alloy and provide more clues for high-efficiency production of the alloy.

      PubDate: 2016-05-05T10:35:22Z
  • Modeling of Liquid Level and Bubble Behavior in Vacuum Chamber of RH
    • Abstract: Publication date: April 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 4
      Author(s): Yi-hong LI, Yan-ping BAO, Rui WANG, Min WANG, Qing-xue HUANG, Yu-gui LI
      In the Ruhrstahl-Heraeus (RH) refining process, liquid steel flow pattern in a ladle is controlled by the fluid flow behavior in the vacuum chamber. Potassium chloride solution and NaOH solution saturated with CO2 were respectively used as a tracer to investigate the liquid and gas flow behaviors in the vacuum chamber. Principal component and comparative analysis were made to show the factors controlling mixing and circulation flow rate. The liquid level and bubble behavior in the vacuum chamber greatly affect fluid flow in RH process. Experiments were performed to investigate the effects of liquid steel level, gas flow rate, bubble residence time, and gas injection mode on mixing, decarburization, and void fraction. The results indicate that the mixing process can be divided into three regions: the flow rate-affected zone, the concentration gradient-affected zone, and their combination. The liquid steel level in the vacuum chamber of 300 mm is a critical point in the decarburization transition. For liquid level lower than 300 mm, liquid steel circulation controls decarburization, while for liquid level higher than 300 mm, bubble behavior is the main controlling factor. During the RH process, it is recommended to use the concentrated bubble injection mode for low gas flow rates and the uniform bubble injection mode for high gas flow rates.

      PubDate: 2016-05-05T10:35:22Z
  • Electroslag Remelting Withdrawing Technology for Offshore Jack-up Platform
           Rack Steel Manufacturing Process
    • Abstract: Publication date: April 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 4
      Author(s): Xi-min ZANG, Tian-yu QIU, Wan-ming LI, Xin DENG, Zhou-hua JIANG, Hua SONG
      Offshore jack-up platform rack steel must exhibit high strength and toughness as well as excellent welding properties. A high-quality large ingot is a prerequisite for obtaining a high-performance rough part. The electroslag remelting withdrawing (ESRW) technology using a T-shaped mold and bifilar mode was introduced to replace casting technology. Numerical simulation of the ESRW process was performed to determine the distribution of the temperature and velocity fields and to determine the optimum process for producing rack steels. Several A514Q slab ingots with dimensions of 0. 32 m × 1. 40 m × 4. 00 m were produced using ESRW technology in an industrial plant. The industrial test indicated that slab ingots produced by the ESRW method exhibited uniform chemical compositions and compact macrostructures. A 115. 4 mm thick plate was produced from the rough ingot after 11 rolling passes. Samples were obtained from different positions in the steel plate to test the mechanical performance and examine the microstructure, and the results revealed that the properties of the steel plate satisfied ASTM standards. The ESRW process improved the tensile strength and toughness of the slab ingot, enabling significant improvements in the anisotropy and low temperature toughness, which are critical for the development of rack steel for offshore platforms.

      PubDate: 2016-05-05T10:35:22Z
  • Precipitation and Solid Solution of Titanium Carbonitride Inclusions in
           Hypereutectoid Tire Cord Steel
    • Abstract: Publication date: April 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 4
      Author(s): Chen-fan YU, Zheng-liang XUE, Wu-tao JIN
      The properties of titanium carbonitride Ti(C x N1–x ) inclusions precipitated during solidification of tire cord steels and the thermodynamic conditions for their decomposition and solid solution during billet heating were investigated using a thermodynamics method. The solid solution of Ti(C x N1–x ) inclusions during high-temperature heating was also studied experimentally. The results revealed that: (1) the higher the content of carbon in the tire cord steel is, the greater the value of x in the Ti(C x N1–x ) inclusions is; (2) the higher the content of carbon in the tire cord steel is, the earlier the Ti(C x N1–x ) inclusions precipitated during the solidification process and the lower the solidification front temperature is during precipitation; (3) when an 82A steel sample was heated to 1087 °C, the Ti(C x N1–x ) inclusions possess the thermodynamic conditions of decomposition and solid solution; and (4) when 82A samples were heated to 1150 and 1250 °C, the total number of Ti(C x N1–x ) inclusions larger than 5 μm in diameter decreased by 55. 0% and 70. 3%, respectively. In addition, although smaller inclusions with diameter less than 2 μm continued to decompose when the sample was heated at 1250 °C for 2 h and then cooled to 1000 °C in the furnace, the number of inclusions larger than 5 μm in diameter increased.

      PubDate: 2016-05-05T10:35:22Z
  • Solidification Structure of Continuous Casting Large Round Billets under
           Mold Electromagnetic Stirring
    • Abstract: Publication date: April 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 4
      Author(s): Tao SUN, Feng YUE, Hua-jie WU, Chun GUO, Ying LI, Zhong-cun MA
      The solidification structure of a continuous casting large round billet was analyzed by a cellular-automaton-finite-element coupling model using the ProCAST software. The actual and simulated solidification structures were compared under mold electromagnetic stirring (MEMS) conditions (current of 300 A and frequency of 3 Hz). Thereafter, the solidification structures of the large round billet were investigated under different superheats, casting speeds, and secondary cooling intensities. Finally, the effect of the MEMS current on the solidification structures was obtained under fixed superheat, casting speed, secondary cooling intensity, and MEMS frequency. The model accurately simulated the actual solidification structures of any steel, regardless of its size and the parameters used in the continuous casting process. The ratio of the central equiaxed grain zone was found to increase with decreasing superheat, increasing casting speed, decreasing secondary cooling intensity, and increasing MEMS current. The grain size obviously decreased with decreasing superheat and increasing MEMS current but was less sensitive to the casting speed and secondary cooling intensity.

      PubDate: 2016-05-05T10:35:22Z
  • Analysis of Crystallization Behavior of Mold Fluxes Containing TiO2 Using
           Single Hot Thermocouple Technique
    • Abstract: Publication date: April 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 4
      Author(s): Yun LEI, Bing XIE, Wen-hui MA
      The crystallization behavior of mold fluxes containing 0—8 mass% TiO2 was investigated using the single hot thermocouple technique (SHTT) and X-ray diffraction (XRD) to study the possible effects on the coordination of heat transfer control and strand lubrication for casting crack-sensitive peritectic steels. Time-temperature-transformation (TTT) and continuous-cooling-transformation (CCT) curves were plotted using the data obtained from SHTT to characterize the crystallization of the mold fluxes. The results showed that crystallization of the mold fluxes during isothermal and non isothermal processes was suppressed with TiO2 addition. From the TTT curves, it could be seen that the incubation and growth time of crystallization increased significantly with TiO2 addition. The CCT curves showed that the crystallization temperature initially decreased, and then suddenly increased with increasing the TiO2 content. XRD analysis suggested the presence of cuspidine in the mold fluxes with lower TiO2 content (< 4 mass%), while both perovskite and cuspidine were detected in the mold fluxes when the TiO2 content was increased to 8 mass%). In addition, the growth mechanisms of the crystals changed during the isothermal crystallization process from interface-controlled growth to diffusion-controlled growth with increasing the TiO2 content.

      PubDate: 2016-05-05T10:35:22Z
  • Self-reduction Mechanism of Coal Composite Stainless Steel Dust Hot
    • Abstract: Publication date: April 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 4
      Author(s): Sok-chol RI, Man-sheng CHU, Shuang-yin CHEN, Zheng-gen LIU, Hun HONG
      To efficiently recycle valuable metals such as chromium and nickel in stainless steel dust, self-reduction experiments were carried out to study the reduction mechanism of metal oxides in coal composite stainless steel dust hot briquette, which is defined as a CCSB here. Self-reduction of CCSB is proceeded by volatile matter and fixed carbon contained within CCSB. Experiments were performed to study the effects of temperature and carbon to oxygen (C/Ocoal) ratio on self-reduction of CCSB. At 1400 and 1450 °C, volatile matter in coal used for experiment could take the place of about 40% of fixed carbon in coal. Under the present experimental conditions, reduction product of chromium appears as FeCr2 O4, Cr2 O3, Cr7 C3, and [Cr] in turn during reduction. To evaluate the formation of metal nuggets in self-reduction process of CCSB, metal nuggets containing chromium and nickel were observed in outside of reduction products under various conditions, and thermodynamic equilibrium calculation was carried out for possible products and formation of molten metal by fixed carbon. SEM and EDS analyses were made for metal nugget and slag in reduced product. The results reveal that it is reasonable to achieve the metal nuggets at 1450 °C, 0. 8 of C/Ocoal ratio and 20 min of reduction time. The nugget formation can indicate one innovative process for comprehensive utilization of stainless steel dust.

      PubDate: 2016-05-05T10:35:22Z
  • Influences of Alloying Elements on Oxidation Behavior of Steels and
           Microstructure of Oxide Scales
    • Abstract: Publication date: March 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 3
      Author(s): Hui-bin WU, Di WANG, Peng-cheng ZHANG, Jin-ming LIANG, Sheng LIU, Di TANG
      In order to figure out the oxidation behavior of steels during heating, five micro-alloyed steels were subjected to continuous and isothermal oxidation using the thermo gravimetric analyzer and the Gleeble-3500 thermo-mechanical simulator. The microstructure of oxide scales, especially the thickness fractions of Fe2O3, Fe3O4 and FeO layers, was analyzed using the scanning electron microscope (SEM), electron probe microanalyzer (EPMA) and electron backscattered diffraction (EBSD) techniques. The micro-alloyed steels containing alloying elements (Si, Cr, Ni and Cu) show a higher oxidation resistance compared with the low carbon steel. It is found that alloying elements accumulated at scale/substrate interface during high temperature oxidation. Alloying elements function in two ways in the oxidation of steels: one is enhancing the scale/substrate interface and consequently suppressing the blister of scales; and the other is impeding the outward diffusion of iron cations from substrate to scales, resulting in the decrease of oxidation rate. As the diffusion of iron cations is impeded, the thickness fractions of Fe2O3 and Fe3O4 of micro-alloyed steels are more than those of low carbon steels.

      PubDate: 2016-03-11T05:41:37Z
  • Effect of Warm Rolling on Micro-deformation Behavior and Mechanical
           Properties of Columnar-grained Fe-6. 5 mass%Si Alloy
    • Abstract: Publication date: March 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 3
      Author(s): Hua-dong FU, Yuan-ke MO, Long-chao ZHUO, Zhi-hao ZHANG, Jian-xin XIE
      Micro-deformation behavior and mechanical properties of columnar-grained Fe-6. 5 mass%Si alloy before and after warm rolling were investigated by means of micro-indentation and three-point bending tests. The results show that the columnar-grained Fe-6. 5 mass%Si alloy before warm rolling presents sink-in mode of micro-indentation, while pile-up mode with a number of arc-shaped deformation bands exists in the warm-rolled alloy. Compared with that of the alloy before warm rolling, the maximum bending fracture stress and maximum bending fracture deflection of the warm-rolled alloy are increased by 96% and 50%, respectively. The different micro-deformation behavior and mechanical properties of the columnar-grained Fe-6. 5 mass%Si alloy are ascribed to the changes of dislocation density, dislocation configuration and long-range order degree, which significantly improve the room temperature plasticity of the alloy after warm rolling.

      PubDate: 2016-03-11T05:41:37Z
  • One-step Crystallization Kinetic Parameters of the Glass-ceramics Prepared
           from Stainless Steel Slag and Pickling Sludge
    • Abstract: Publication date: March 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 3
      Author(s): Shen-gen ZHANG, Jian YANG, Bo LIU, De-an PAN, Chun-li WU, Alex A. VOLINSKY
      One-step crystallization is one of the most energy conserving methods for glass-ceramics preparation. However, only a few kinetics studies focused on the glass-ceramics prepared by the one-step crystallization. The one-step crystallization kinetic parameters were studied using differential scanning calorimetry. The activation energy (E a) and the Avrami parameter (n) were calculated as 152. 79 kJ · mol−1 and 4. 39, respectively. These parameters indicate that continuous nucleation and three-dimensional crystal growth are the dominating mechanisms in the one-step crystallization process of the parent glass. The properties of the obtained glass-ceramics can be compared to the glass-ceramics prepared by the two-stage heat treatment and sintering method. This crystallization kinetics research can be used to evaluate the one-step crystallization potential of a parent glass.

      PubDate: 2016-03-11T05:41:37Z
  • Forming Limit and Thickness Transition Zone Movement for Tailor Rolled
           Blank during Drawing Process
    • Abstract: Publication date: March 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 3
      Author(s): Hua-wei ZHANG, Xiang-hua LIU, Li-zhong LIU, Ping HU, Jia-lu WU
      The process of automobile lightweight can be promoted by the application of tailor rolled blank (TRB) in the automobile industry. Therefore, research on the formability of TRB is of good practical significance and application value because of the enormous potential of TRB in the aspect of automobile lightweight. Aiming at the present condition of lack of researches on the influence of characteristic parameters on TRB drawing process, the drawing formability of TRB was studied with a combination method of simulation and experiment by taking square box as the research object. Firstly, drawing simulation and experiment of TRB were carried out. Then, effects of thickness transition zone (TTZ) position and blank size on the drawing formability of TRB were analyzed. Forming limit and TTZ movement for TRB square box during the drawing process were respectively discussed, when transition zones of TRB were located at different positions and blanks were of different sizes. The results indicate that lubrication condition exerts greater influence on TRB forming limit in comparison with TTZ movement, and the smaller blank size and TTZ being located at the blank center or slightly offset to the thinner side are preferable for acquiring greater forming limit and smaller TTZ movement.

      PubDate: 2016-03-11T05:41:37Z
  • Effects of Temperature and Strain Rate on Flow Behavior and
           Microstructural Evolution of Super Duplex Stainless Steel under Hot
    • Abstract: Publication date: March 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 3
      Author(s): Ming MA, Hua DING, Zheng-you TANG, Jing-wei ZHAO, Zhou-hua JIANG, Guang-wei FAN
      Hot compression tests were carried out in the temperature range of 1223–1473 K and strain rate range of 0. 01–30 s−1 to investigate the flow behavior and microstructural evolution of super duplex stainless steel 2507 (SDSS2507). It is found that most of the flow curves exhibit a characteristic of dynamic recrystallization (DRX) and the flow stress increases with the decrease of temperature and the increase of strain rate. The apparent activation energy Q of SDSS2507 with varying true strain and strain rate is determined. As the strain increases, the value of Q declines in different ways with varying strain rate. The microstructural evolution characteristics and the strain partition between the two constituent phases are significantly affected by the Zener-Hollomon parameter (Z). At a lower lnZ, dynamic recovery (DRV) and continuous dynamic recrystallization (CDRX) of the ferrite dominate the softening mechanism during the compression. At this time, steady state deformation takes place at the last stage of deformation. In contrast, a higher lnZ will facilitate the plastic deformation of the austenite and then activate the discontinuous dynamic recrystallization (DDRX) of the austenite, which leads to a continuous decline of the flow stress even at the last deformation stage together with CDRX of the ferrite.

      PubDate: 2016-03-11T05:41:37Z
  • Descaling Behavior of 430 Hot-rolled Stainless Steel in HCl-based Solution
    • Abstract: Publication date: March 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 3
      Author(s): Ying-ying YUE, Cheng-jun LIU, Pei-yang SHI, Mao-fa JIANG, Li-yan QIN, Guang-wei FAN
      Descaling of hot-rolled stainless steel is generally implemented through pickling process in HNO3-HF mixed acids, which induces severe environmental concerns of nitrogen oxide (NO x ) gases and nitrites. According to the electrochemical measurement, the mass loss test and the appearance analysis, a new pickling process which employed HCl-based solution was proposed and evaluated to provide theoretical basis for the development of environment-friendly and highly effective pickling process. Under the experimental condition, the HCl-based solution can compete with ordinary HNO3-HF mixed acids in terms of pickling efficiency, surface integrity and the removal of Cr-depleted layer. The descaling process of 430 hot-rolled stainless steel in the HCl-based solution consisted of three steps. The descaling solution penetrated the oxide scales into the underlying metal, dissolving the Cr-depleted layer and part of substrates. The oxide scales peeled off from the stainless steel and a polished and smooth surface was exposed. The descaled stainless steel was dissolved uniformly in the HCl-based solution; therefore, the pickling duration was vital for desired surface integrity. Under the static condition, the appropriate descaling time of 430 hot-rolled stainless steel in HCl-based solution was 400 s.

      PubDate: 2016-03-11T05:41:37Z
  • Reduction of Carbon-bearing Pellets of Oolitic Hematite in a Shaft Furnace
    • Abstract: Publication date: March 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 3
      Author(s): Wei WU, Jian-jun GAO, Jia-qing ZENG, Yuan-hong QI, Jian-chang WANG, Xi-dong ZHANG
      When carbon-bearing pellets of oolitic hematite are treated in a shaft furnace, some problems are typically encountered: the metallization ratio of the metal pellets is low; the carbon-bearing pellets bond with each other at high temperatures; and the separation of phosphorus from iron is difficult. To solve these problems, experiments were conducted on oolitic hematite reduction in a resistance furnace and semi-industrial test shaft furnace. The results showed that the metallization rate reached 90% or greater under the conditions of a reduction temperature of 1150 °C, an atmosphere of simulated flue gas, and a reduction time between 1. 5 and 2. 0 h. The problem of high-temperature bonding among pellets can be solved by increasing the strength of the pellets, coating their surface with a surface transfer agent and maintaining an even temperature inside the shaft furnace. The basicity of the ore blend exerted no obvious effect on the magnetic concentrate and phosphorus content. The phosphorus content in the magnetic concentrate can be further reduced by improving the grinding capacity of the ball mills used in the experiments. On the basis of the experimental results related to oolitic hematite reduction with carbon-bearing pellets in a shaft furnace, the experimental requirements were satisfied with an average 88. 27% total Fe content and 0. 581% P content in the pellets.

      PubDate: 2016-03-11T05:41:37Z
  • Recognition of Blast Furnace Gas Flow Center Distribution Based on
           Infrared Image Processing
    • Abstract: Publication date: March 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 3
      Author(s): Lin SHI, You-bin WEN, Guang-sheng ZHAO, Tao YU
      To address the problems about the difficulty in accurate recognition of distribution features of gas flow center at blast furnace throat and determine the relationship between gas flow center distribution and gas utilization rate, a method for recognizing distribution features of blast furnace gas flow center was proposed based on infrared image processing, and distribution features of blast furnace gas flow center and corresponding gas utilization rates were categorized by using fuzzy C-means clustering and statistical methods. A concept of gas flow center offset was introduced. The results showed that, when the percentage of gas flow center without offset exceeded 85%, the average blast furnace gas utilization rate was as high as 41%; when the percentage of gas flow center without offset exceeded 50%, the gas utilization rate was primarily the center gas utilization rate, and exhibited a positive correlation with no center offset degree; when the percentage of gas flow center without offset was below 50% but the sum of the percentage of gas flow center without offset and that of gas flow center with small offset exceeded 86%, the gas utilization rate depended on both the center and the edges, and was primarily the edge gas utilization rate. The method proposed was able to accurately and effectively recognize gas flow center distribution state and the relationship between it and gas utilization rate, providing evidence in favor of on-line blast furnace control.

      PubDate: 2016-03-11T05:41:37Z
  • Prediction of Critical Conditions for Dynamic Recrystallization in 316LN
           Austenitic Steel
    • Abstract: Publication date: March 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 3
      Author(s): Xin-gang LIU, Li-ge ZHANG, Rong-sheng QI, Lei CHEN, Miao JIN, Bao-feng GUO
      Hot compression experiments conducted on a Gleeble-3500 thermo-mechanical simulator and metallographic observation tests were employed to study the critical conditions of dynamic recrystallization (DRX) of 316LN austenitic stainless steel. The true stress-true strain curves of 316LN were obtained at deformation temperatures ranging from 900 °C to 1200 °C and strain rates ranging from 0. 001 s−1 to 10 s−1 . Based on the above tests, the critical conditions of DRX were determined and compared with those obtained from work-hardening theory and the Cingara-McQueen flow stress model. Furthermore, the microstructure was observed to validate the calculated results. The ratio of critical strain to peak strain (ɛ c/ɛ p) for 316LN was determined, and the quantitative relationship between the critical strain and the deformation parameters of 316LN was elucidated. The results demonstrated that the onset of DRX corresponds to the constant normalized strain hardening rate (Γ), namely, the critical strain hardening rate Γ c for 316LN is equal to 0. 65.

      PubDate: 2016-03-11T05:41:37Z
  • Effect of Soda Ash on Properties of Mold Flux and Mineralogical Structures
           of Flux Film
    • Abstract: Publication date: March 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 3
      Author(s): Xiu-li HAN, Yi-fei ZHANG, Lei LIU, Li-na LIU, Han ZHANG
      During continuous casting, properties of mold flux and mineralogical structures of flux film play important roles in controlling steel quality. The effect of soda ash on the physical properties and crystallization characteristics of mold flux was investigated using process mineralogy, including polarizing microscopy, X-ray diffraction, and electron microprobe, etc. Mold flux was mainly prepared using cement clinker and industrial mineral materials under laboratory conditions, and the mineralogical structures of the flux film were systematically identified and quantitatively analyzed. The results showed that, by increasing the soda ash content from 10 mass% to 18 mass%, the crystallization temperature, critical cooling rate and crystallization ratio of the flux film decreased, but the crystallization ratio still reached 75% after adding soda ash, and the mineral compositions and microstructures of the flux film changed slightly. When the soda ash content exceeded 14 mass%, the critical cooling rate and the crystallization ratio decreased slightly, whereas the mineral content of the flux film changed evidently, with a large amount of cuspidine precipitation and a significant decrease in the wollastonite content until it reached zero, which resulted in deterioration of the lubrication of the flux film.

      PubDate: 2016-03-11T05:41:37Z
  • Wear Behavior and Mechanism of a Sliding Pair of 0. lC-3Cr-2W-V Nitrided
           Steel Rubbing against an Aluminum Bronze Alloy
    • Abstract: Publication date: March 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 3
      Author(s): Guang-hong WANG, Sheng-guan QU, Zhi-hua XIONG, Fu-qiang LAI, Xiao-qiang LI, Mao-sheng YANG
      Wear behavior and mechanism of plasma nitrided steel oscillating against a heat-treated and an untreated aluminum bronze alloy were investigated using an Optimol SRV tribometer. The influence of heat treatment on the mechanical properties of the alloy was evaluated. Furthermore, the wear debris was also examined to understand the wear mechanisms. The results show that a 220–230 μm nitrided layer, which was harder than the substrate, was obtained on the steel surface. The tensile strength and hardness of the alloy are found to be significantly improved by the heat treatment associated with low impact toughness. The heat treatment of the alloy did not obviously decrease the friction coefficient of the nitrided steel-bronze couple. However, the wear loss of the nitrided steel increased when it mated with the treated bronze by a severe three-body abrasion. The nitrided steel was mainly damaged by fatigue spalling. Under plane contact conditions, the wear debris was mainly generated from the bronze part and can escape from the interface before being oxidized, leading to the phase structure of all the debris being copper rather than copper oxides.

      PubDate: 2016-03-11T05:41:37Z
  • Factors Affecting the Mechanical Properties of Ultra-high-strength
           Bainitic Steel Containing W and 0.33 mass% C
    • Abstract: Publication date: March 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 3
      Author(s): Shi-meng ZHOU, Xing-wang CHENG, You-jing ZHANG, Meng WANG, Wen JIANG, Hong-nian CAI
      A novel ultra-high-strength bainitic steel was designed. The analysis of its mechanical properties by quasistatic testing showed that upper bainitic steel exhibited an ultimate tensile strength of 2260 MPa (engineering stress) and an ultimate compressive strength of more than 2700 MPa (true stress). The ultra-high strength of upper bainitic steel was mainly attributed to untempered martensite and upper bainite with a feather-like microstructure. Moreover, lower bainitic steel demonstrated an ultimate tensile strength of 1922 MPa (engineering stress) and an ultimate compressive strength of 2500 MPa (true stress). The ultra-high strength of lower bainitic steel was primarily due to untempered martensite and lower bainite with an acicular microstructure. The untempered martensite in the two kinds of bainitic steels was produced in different ways. The dynamic test results showed that the ultimate compressive strengths of the two bainitic steels were maintained at 1600 MPa (true stress) under high strain rates (1100 and 2200 s−1) at 600 °C, because of the added tungsten, confirming the satisfactory hot hardness property of the steel. Furthermore, lower bainitic steel showed better comprehensive mechanical properties than upper bainitic steel.

      PubDate: 2016-03-11T05:41:37Z
  • Microstructure and Properties of Fe-Cr-C Hardfacing Alloys Reinforced with
    • Abstract: Publication date: March 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 3
      Author(s): Hai-yun LIU, Zhi-liang SONG, Qing CAO, Shao-ping CHEN, Qing-sen MENG
      The hypereutectic Fe-Cr-C hardfacing alloys with different contents of TiB2 and Nb were prepared by self-shielded flux cored arc welding. The microstructure of a series of hypereutectic Fe-Cr-C hardfacing alloys added with various TiB2 and Nb contents was investigated by using optical microscopy (OM), scanning electron microscopy (SEM) and X-ray diffraction (XRD). In addition, their Rockwell hardness, microhardness and resistance to abrasive wear were tested. The results showed that the microstructure of a series of hypereutectic Fe-Cr-C hardfacing alloys consisted mainly of martensite, austenite, primary M7C3 carbides and eutectic M7C3 carbides. With the addition of TiB2, a new hard-phase TiC was produced in the hardfacing alloys. And in the alloys added with TiB2 and Nb, a new hard composite phase TiC-NbC was formed. The microhardness of the matrix was improved by adding TiB2 and Nb, but the effect on the Rockwell hardness of Fe-Cr-C hardfacing alloys was insignificant. The addition of TiB2 and Nb can also decrease the size of the primary M7C3 carbides and make the primary M7C3 homogeneous. As a result, the reinforced matrix, the more homogeneous primary M7C3 carbides, and the new hard-phase TiC-NbC all improved the wear resistance of Fe-Cr-C hardfacing alloys.

      PubDate: 2016-03-11T05:41:37Z
  • Effect of Temperature on Microstructure and Formability of Al-10 mass% Si
    • Abstract: Publication date: March 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 3
      Author(s): Jie ZHANG, She-ming JIANG, Qi-fu ZHANG, Chang-sheng LIU
      The type-1 aluminized (Al-10 mass% Si) coating on hot stamped steel is used in commercial applications. The effect of temperature on microstructure and formability of the Al-10 mass% Si coating was investigated. Hot-dip aluminized 22MnB5 steel was heated at 870, 900, 930, and 1050 °C for 5 min. After heat treatment at different temperatures, the microstructure of Al-10 mass% Si was characterized by field-emission scanning electron microscopy and energy-dispersive spectroscopy. The results show that when the Al-10 mass% Si coating was heated at 870 °C for 5 min, three types of intermetallic phases were formed: two ternary Fe-Si-Al phases (Fe2 SiAl7 + Fe2 Si2 Al5, and Fe2 SiAl2 + Fe2Si2Al5) and one binary Fe-Al phase (FeAl3). The phases in the coating became Fe2SiAl2 + Fe2Si2 Al5 and FeAl3, the binary Fe-Al phase near the interface became Fe2Al5 and the Si-rich layers were decreased with the increase of heating temperature. When the heat treatment was 1050 °C for 5 min, the Si-rich layer disappeared, the coating consisted of FeAl and Fe3Al, and the Kirkendall voids were formed. When the heating temperature was increased through 870, 900, and 930 °C, the coating hardness was reduced and cracks were formed in the coating after hot stamping. The formability of the coating with temperature change was confirmed by a hot stamping test. When heated at 1050 °C, the coating was formable but continuous Kirkendall voids were observed.

      PubDate: 2016-03-11T05:41:37Z
  • Microstructure and Mechanical Properties of NANOBAIN Steel
    • Abstract: Publication date: March 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 3
      Author(s): Yao HUANG, Xue-li ZHANG, Wei-ning LIU, Xu-min WANG, Jun-ke HAN
      The microstructure and mechanical properties of NANOBAIN steel treated at different isothermal temperatures were investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEEM), uniaxial tensile tests and X-ray diffraction (XRD). It was found that bainitic ferrite (BF) plate was made of basic shear transformation units arranged in the same direction of subunits. The existence of defects, such as nanoscale twinning and dislocation, suggested that the growth of transformation units was controlled by the surrounding defect plane with dislocation, which was consistent with the moving direction of BF/austenite interface parallel to the twinning plane. The behavior of work hardening indicated that mechanical stability of microstructures obtained at 250 °C and 300 °C was much more stable than that obtained at 210 °C. The evolution of carbon partitioning in retained austenite and bainitic ferrite also indicated that austenite was enriched in carbon at the initial stage step by step; after the formation of BF, the austenite did not seem to be greatly enriched in carbon and the carbon content showed a little decrease instead; subsequently, a phenomenon of little decarburization of supersaturated bainitic ferrite has also been found.

      PubDate: 2016-03-11T05:41:37Z
  • EBSD Investigation on Effect of Cooling Rate on Microstructure and
           Transformation Textures of High Strength Hot-rolled Steel Plates
    • Abstract: Publication date: March 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 3
      Author(s): Nancy M. LOPEZ GRANADOS, Armando SALINAS RODRIGUEZ
      The effect of cooling rate on the microstructure and transformation textures of high strength hot-rolled steels was investigated. Heat treated samples subjected to different cooling conditions were characterized by optical and scanning electron microscopes using orientation imaging microscopy (OIM). The experimental results demonstrate that there is a significant effect of cooling rate on microstructures and textures resulting from phase transformation. Slow cooling rates lead to the appearance of the cube (001) [0 0], rotated cube (001) [ 0]/(001) [1 0], Goss (110)[001] and rotated Goss (110) [1 0] components. In contrast, textures developed at rapid cooling rates are preferably of Cu (112)[11 ], Br (110) [11 ], transformed Cu (113) [1 0] and transformed Br (332) [113]/(112) [1 1]. These texture changes are attributed to the selective character of the phase transformation. The OIM technique was used to have a better understanding of the formation of phases and their relationship between microstructure and processing conditions. The volume fraction of micro-constituents resulting from phase transformation such as bainite, martensite and different types of ferrite, can be measured satisfactorily by this technique correlating image quality of EBSD patterns to specific phases.

      PubDate: 2016-03-11T05:41:37Z
  • Influence of Na2CO3 as Additive on Direct Reduction of Boron-bearing
           Magnetite Concentrate
    • Abstract: Publication date: February 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 2
      Author(s): Yong-li LI, Jing-kui QU, Guang-ye WEI, Tao QI
      Boron-bearing magnetite concentrate is typically characterized by low grade of iron and boron (w TFc = 51 %— 54 %, w B2O3 = 6 % — 8%), as well as the close intergrowth of ascharite phase and magnetite phase. A promising technology was proposed to separate iron and boron by coupling the direct reduction of iron oxides and Na activation of boron minerals together. The influence of Na2CO3 as additive on the direct reduction of boron-bearing magnetite was studied by chemical analysis, kinetic analysis, XRD analysis and SEM analysis. The results showed that the addition of Na2CO3 not only activated boron minerals, but also reduced the activation energy of the reaction and promoted the reduction of iron oxides. Besides, the addition of Na2CO3 changed the composition and melting point of non-ferrous phase, and then promoted the growth and aggregation of iron grains, which was conducive to the subsequent magnetic separation. Thus, the coupling of the two processes is advantageous.

      PubDate: 2016-02-09T15:38:20Z
  • Thermodynamic Analysis and Experimental Study on Reaction of CO2 Gas with
           Hot Metal
    • Abstract: Publication date: February 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 2
      Author(s): Guo WEI, Zhi-tao LI, Zi-liang LI, Qiang-jian GAO, Feng-man SHEN
      The reaction of CO2 gas with hot metal was investigated based on the thermodynamic analysis and experimental results. It shows that both silicon and carbon in hot metal can be oxidized by CO2 gas in the temperature range of 1300— 1500 °C. When using graphite crucible, temperature has little influence on final mass percent of carbon W [c] because of the carburization effect. Decarburization degree rises significantly with increasing gas injection rate and W [c] can be reduced to 3.2% at most when using MgO crucible. Lower temperature or higher gas injection rate is propitious to promote desilication reaction, but only 5% — 10% of desilication ratio could be obtained in 20 min. The final mass percent of silicon W [Si] when using MgO crucible is lower than that when using graphite crucible. Experimental results also demonstrate that CO2 injection has no effect on the concentration of manganese, sulfur and phosphorus in hot metal. In view of the weak oxidation ability and temperature drop of hot metal, CO2 gas is suggested to be used as carrier gas in desilication process rather than oxidizing agent.

      PubDate: 2016-02-09T15:38:20Z
  • Flow Characteristics and Inclusion Removal in a Ten-strand Continuous
           Casting Tundish: Physical Modelling and Industrial Trials
    • Abstract: Publication date: February 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 2
      Author(s): Shu-guo ZHENG, Miao-yong ZHU, Ye-lian ZHOU, Wang SU
      The flow characteristics and inclusion removal in a ten-strand continuous casting tundish were investigated with physical modelling and industrial trials. The results show that, among the strands, the strand with the minimum dimensionless time of the first appearance of tracer at the tundish exit appears to be the worst one for inclusion removal, while the strand with the maximum dimensionless mean residence time shows the best inclusion removal efficiency. The inclusion number decreases with increasing inclusion size for all strands. The inclusion number distribution among strands is the same for all inclusion sizes and the descending order of inclusion number is basically consistent with the ascending order of dimensionless mean residence time among individual strands. However, when the strand with the minimum dimensionless time of the first appearance of tracer at the tundish exit is not the same one with the minimum dimensionless mean residence time, the former seems to be inferior to the latter for inclusion removal.

      PubDate: 2016-02-09T15:38:20Z
  • Analysis of Non-uniform Mechanical Behavior for a Continuous Casting Mold
           Based on Heat Flux from Inverse Problem
    • Abstract: Publication date: February 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 2
      Author(s): Feng-ming DU, Xu-dong WANG, Yu LIU, Tian-yi LI, Man YAO
      The distortion of mold plates plays an important role in the formation of surface cracks on continuously cast steel products. To investigate the non-uniform distortion of a mold, a full-scale stress model of the mold was developed. An inverse algorithm was applied to calculate the heat flux using the temperatures measured by the thermocouples buried inside the mold plates. Based on this, a full-scale, finite-element stress model, including four copper plates, a nickel layer and water slots in different depths, was built to determine the complex mechanical behavior of the continuous casting mold used to produce steel slabs. The heat flux calculated by the inverse algorithm was applied to the stress model to analyze the non-uniform mechanical behavior. The results showed that the stress and distortion distributions of the four copper plates were not symmetrical, which reflected the non-uniform distortion behaviors of copper plates, water slots, nickel layer and the corner region of the mold. The gap between the mold and the slab was increased because of the corner distortion, which was very important for the heat transfer of initial solidifying shell, and it may be a major reason for the slow cooling of the slab corner.

      PubDate: 2016-02-09T15:38:20Z
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