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  Subjects -> ENVIRONMENTAL STUDIES (Total: 768 journals)
    - ENVIRONMENTAL STUDIES (704 journals)
    - POLLUTION (22 journals)
    - TOXICOLOGY AND ENVIRONMENTAL SAFETY (34 journals)
    - WASTE MANAGEMENT (8 journals)

ENVIRONMENTAL STUDIES (704 journals)            First | 1 2 3 4 5 6 7 8     

International innovation. Environment     Open Access  
International Journal of Acarology     Hybrid Journal   (Followers: 1)
International Journal of Advancement in Earth and Enviromental Sciences     Open Access   (Followers: 2)
International Journal of African Renaissance Studies - Multi-, Inter- and Transdisciplinarity     Hybrid Journal   (Followers: 2)
International Journal of Agricultural and Environmental Information Systems     Full-text available via subscription   (Followers: 1)
International Journal of Alternative Propulsion     Hybrid Journal   (Followers: 1)
International Journal of Applied Psychoanalytic Studies     Hybrid Journal   (Followers: 2)
International Journal of Chinese Culture and Management     Hybrid Journal   (Followers: 1)
International Journal of Corrosion     Open Access   (Followers: 10)
International Journal of Critical Infrastructures     Hybrid Journal   (Followers: 3)
International Journal of Disaster Risk Reduction     Hybrid Journal   (Followers: 5)
International Journal of Disaster Risk Science     Open Access   (Followers: 8)
International Journal of Ecological Economics and Statistics     Full-text available via subscription   (Followers: 1)
International Journal of Ecology     Open Access   (Followers: 8)
International Journal of Ecology & Development     Full-text available via subscription   (Followers: 1)
International Journal of Energy and Environmental Engineering     Open Access   (Followers: 2)
International Journal of Environment     Open Access   (Followers: 3)
International Journal of Environment and Health     Hybrid Journal   (Followers: 7)
International Journal of Environment and Pollution     Hybrid Journal   (Followers: 6)
International Journal of Environment and Sustainable Development     Hybrid Journal   (Followers: 13)
International Journal of Environment and Waste Management     Hybrid Journal   (Followers: 6)
International Journal of Environment, Workplace and Employment     Hybrid Journal   (Followers: 3)
International Journal of Environmental Engineering     Hybrid Journal   (Followers: 5)
International Journal of Environmental Health Engineering     Open Access  
International Journal of Environmental Health Research     Hybrid Journal   (Followers: 3)
International Journal of Environmental Policy and Decision Making     Hybrid Journal   (Followers: 10)
International Journal of Environmental Protection     Open Access   (Followers: 12)
International Journal of Environmental Research and Public Health     Open Access   (Followers: 14)
International Journal of Environmental Science and Technology     Hybrid Journal   (Followers: 4)
International Journal of Environmental Studies     Hybrid Journal   (Followers: 11)
International Journal of Exergy     Hybrid Journal   (Followers: 3)
International Journal of Forest, Soil and Erosion     Open Access   (Followers: 3)
International Journal of Global Environmental Issues     Hybrid Journal   (Followers: 4)
International Journal of Global Warming     Hybrid Journal   (Followers: 5)
International Journal of Greenhouse Gas Control     Partially Free   (Followers: 5)
International Journal of Health Planning and Management     Hybrid Journal   (Followers: 6)
International Journal of Hygiene and Environmental Health     Hybrid Journal   (Followers: 5)
International Journal of Logistics Research and Applications : A Leading Journal of Supply Chain Management     Hybrid Journal   (Followers: 9)
International Journal of Philosophical Studies     Hybrid Journal   (Followers: 3)
International Journal of Phytoremediation     Hybrid Journal   (Followers: 1)
International Journal of Process Systems Engineering     Hybrid Journal   (Followers: 1)
International Journal of Recycling of Organic Waste in Agriculture     Open Access   (Followers: 1)
International Journal of Regulation and Governance     Hybrid Journal   (Followers: 2)
International Journal of Reliability and Safety     Hybrid Journal   (Followers: 5)
International Journal of Renewable Energy Development     Open Access   (Followers: 5)
International Journal of Social Sciences and Management     Open Access  
International Journal of Soil, Sediment and Water     Open Access   (Followers: 8)
International Journal of Stress Management     Full-text available via subscription   (Followers: 8)
International Journal of Sustainable Construction Engineering and Technology     Open Access   (Followers: 7)
International Journal of Sustainable Engineering     Hybrid Journal   (Followers: 7)
International Journal of Sustainable Materials and Structural Systems     Hybrid Journal   (Followers: 5)
International Journal of Sustainable Society     Hybrid Journal   (Followers: 7)
International Journal of Testing     Hybrid Journal   (Followers: 1)
International Journal of the Commons     Open Access   (Followers: 2)
International Journal of Toxicology     Hybrid Journal   (Followers: 6)
International Journal of Water Resources and Environmental Engineering     Open Access  
International Review of Environmental and Resource Economics     Full-text available via subscription  
International Studies in the Philosophy of Science     Hybrid Journal   (Followers: 9)
Interventions : International Journal of Postcolonial Studies     Hybrid Journal   (Followers: 5)
IOP Conference Series: Earth and Environmental Science     Open Access   (Followers: 7)
Iranian Journal of Environmental Health Science & Engineering     Open Access   (Followers: 1)
Iranian Studies     Hybrid Journal   (Followers: 8)
Irish Educational Studies     Hybrid Journal   (Followers: 1)
Irish Journal of Earth Sciences     Full-text available via subscription  
Irish Political Studies     Hybrid Journal   (Followers: 7)
ISLE: Interdisciplinary Studies in Literature and Environment     Hybrid Journal   (Followers: 2)
Isotopes in Environmental and Health Studies     Hybrid Journal   (Followers: 2)
Israel Studies     Full-text available via subscription   (Followers: 5)
ISRN Ecology     Open Access  
ISRN Environmental Chemistry     Open Access  
Italian Studies     Hybrid Journal   (Followers: 6)
Jahangirnagar University Environmental Bulletin     Open Access  
Journal of Bioremediation & Biodegradation     Open Access   (Followers: 2)
Journal of Earth Science & Climatic Change     Open Access   (Followers: 8)
Journal of Petroleum & Environmental Biotechnology     Open Access   (Followers: 2)
Journal of Advances in Environmental Health Research     Open Access  
Journal of Agricultural and Environmental Ethics     Hybrid Journal   (Followers: 6)
Journal of Agricultural Biotechnology and Sustainable Development     Open Access  
Journal of Agriculture and Environment     Open Access  
Journal of Agriculture and Environment for International Development     Open Access   (Followers: 6)
Journal of Agrobiology     Open Access   (Followers: 2)
Journal of Applied Ecology     Hybrid Journal   (Followers: 137)
Journal of Applied Meteorology and Climatology     Full-text available via subscription   (Followers: 7)
Journal of Applied Psychoanalytic Studies     Hybrid Journal   (Followers: 1)
Journal of Applied Sciences and Environmental Management     Open Access   (Followers: 1)
Journal of Applied Sciences in Environmental Sanitation     Open Access   (Followers: 5)
Journal of Applied Toxicology     Hybrid Journal   (Followers: 9)
Journal of Applied Volcanology     Open Access   (Followers: 6)
Journal of Arid Environments     Hybrid Journal   (Followers: 8)
Journal of Asian Studies     Full-text available via subscription   (Followers: 20)
Journal of Biochemical and Molecular Toxicology     Hybrid Journal   (Followers: 5)
Journal of Black Studies     Hybrid Journal   (Followers: 3)
Journal of Chemical Ecology     Hybrid Journal   (Followers: 1)
Journal of Chemical Health and Safety     Hybrid Journal   (Followers: 2)
Journal of Climate     Full-text available via subscription   (Followers: 21)
Journal of Coastal Research     Full-text available via subscription   (Followers: 11)
Journal of Contaminant Hydrology     Hybrid Journal   (Followers: 9)
Journal of Contemporary European Studies     Hybrid Journal   (Followers: 3)
Journal of East African Natural History     Full-text available via subscription   (Followers: 5)
Journal of Ecology     Hybrid Journal   (Followers: 34)

  First | 1 2 3 4 5 6 7 8     

Journal Cover Journal of Iron and Steel Research, International
   [9 followers]  Follow    
   Full-text available via subscription Subscription journal
     ISSN (Print) 1006-706X
     Published by Elsevier Homepage  [2563 journals]   [SJR: 0.586]   [H-I: 13]
  • Mathematical Modeling of Carbon Content and Intercritical Annealing
           Temperature in DP Steels by Factorial Design Method
    • Abstract: Publication date: July 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 7
      Author(s): Gülcan TOKTAS , Alaaddin TOKTAS , Aslan Deniz KARAOGLAN
      2 k factorial design is employed to find the mathematical relation between the carbon content and intercritical annealing temperature (IAT) in order to predict the responses namely martensite volume fraction (MVF), microhardness (H), yield strength (YS), ultimate tensile strength (UTS), total elongation (TEL), yield ratio (YR) and Charpy impact energy (CIE) in dual phase (DP) steels. Steels containing different carbon contents (0.085% C and 0.380/4) C) had been chosen for this purpose. The main advantages of factorial design are its easy implementation and the effective computation compared with the other optimization techniques, which were employed for predicting mentioned responses in the literature. To verify the proposed approach based on factorial design, experiments for verification were performed. The results of the verification experiments and the mathematical models are in accordance with each other and the literature.


      PubDate: 2014-07-28T03:11:42Z
       
  • Microstructural Characterization of Welded Joint in Duplex Stainless Steel
           by Laser Continuous Heat Treatment
    • Abstract: Publication date: July 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 7
      Author(s): He-ping LIU , Bin LIU , Da-zhao LI , Hu-er SUN , Feng-er SUN , Xue-jun JIN
      Microstructural characterization in fusion zone of the laser continuous heat treatment welded joint was investigated. The results showed that the martensite-like microstructure is the face centered cubic (FCC) crystal structure so that it can be identified as the secondary austenite. The dislocation is observed inside and outside the secondary austenite, whereas inclusion is not found in the vicinity of the secondary austenite. In the fusion zone, there is a kind of carbide precipitate which is identified as M23 C6 by the means of transmission electron microscope (TEM). The carbide precipitate is a representative mode of transformation, which can be generated by the eutectoid reaction. Furthermore, the formation mechanisms of the secondary austenite and chromium carbide are analyzed.


      PubDate: 2014-07-28T03:11:42Z
       
  • Effect of Ti on Austenite Grain Growth Behavior in High Carbon Steels
    • Abstract: Publication date: July 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 7
      Author(s): Han MA , Shu-lun LIAO , Shi-fang WANG
      Austenite grain growth behavior of two high carbon steels was observed using Confocal Laser Scanning Microscope (CLSM). Apparent austenite grain sizes for different holding time under a series of temperatures were measured by employing linear intercept method. Experimental results showed that Ti-bearing steel exhibited a much sluggish growth rate compared with Ti-free counterpart, which was attributed to the pinning effect of Ti(C, N) nanoparticles with the size of 20 to 40 nm on austenite grain boundaries. Based on the research conducted by using Transmission Electron Microscope (TEM) observation and Thermo-Calc calculation, Ti(C, N) was confirmed to be the dominant phase at elevated temperature. Some models were introduced to predict the grain sizes of both steels. By comparison, the results predicted by the modified Gladman equation are found to be closest to the experimental results, which could be employed to predict accurately the austenite grain growth of high carbon steels.


      PubDate: 2014-07-28T03:11:42Z
       
  • Influence of Heat Treatment on Hydroformability of TRIP Seamless Steel
           Tube
    • Abstract: Publication date: July 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 7
      Author(s): Zi-cheng ZHANG , Ken-ichi MANABE
      A low-carbon TRIP seamless steel tube, which is expected to be used in the hydroforming process, was successfully fabricated using piercing, cold-drawing and two-stage heat treatment process. The two-stage heat treatment is one crucial step because it significantly affects the microstructure and mechanical properties of TRIP seamless steel tube. In order to obtain the TRIP seamless steel tube with high hydroformability, several different heat treatment processes were conducted. The effects of heat treatment conditions (intercritical annealing (IA) and isothermal bainite treatment (IBT)) on the TRIP seamless steel tube hydroformability which was determined by free hydraulic bulge test were analyzed. Two different internal pressure boosting velocities of 0.2 and 0.5 MPa/s of free hydraulic bulge tests were adopted to determine the effective stress vs. effective strain curve of TRIP seamless steel tube. The results showed that for the predetermined IA condition, the maximum bulge height increased, but the maximum burst internal pressure decreased, with the increase of IBT holding time from 4 to 6 min. For the predetermined IBT condition, the maximum bulge height decreased, but the maximum burst internal pressure increased, with the increase of IA holding time from 5 to 10 min. By analyzing the free hydraulic bulge test results, it was found that the maximum bulge heights of TRIP seamless steel tubes with the internal pressure boosting velocity of 0.5 MPa/s were higher than those when the internal pressure boosting velocity was 0.2 MPa/s. This means that an appropriate deformation rate should be chosen to obtain the optimal hydroformability of TRIP seamless steel tube. In addition, the effective stress vs. effective strain curves of TRIP seamless steel tubes were obtained with free hydraulic bulge test.


      PubDate: 2014-07-28T03:11:42Z
       
  • Effects of Normalizing Annealing on Grain-oriented Silicon Steel
    • Abstract: Publication date: July 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 7
      Author(s): Chen LING , Li XIANG , Sheng-tao QIU , Yong GAN
      The grain-oriented silicon steel is a kind of important magnetic materials with low iron loss and high induction. Hot band normalizing annealing is an important process which influences the microstructure and the development of the inhibitors. The effects of different annealing temperatures and cooling conditions on the inhibitors and microstructures of normalizing annealing band were investigated. The microstructure and different kinds of the inhibitors, i.e., AlN, AlN+Cu x S+ MnS, and TiN, were discovered. The result shows that a suitable cooling condition leads to more nano-scale inhibitors and uniform microstructure of the normalizing annealing band and consequently results in better magnetic properties.


      PubDate: 2014-07-28T03:11:42Z
       
  • Microstructure Refinement and Property Improvement of Metastable
           Austenitic Manganese Steel Induced by Electropulsing
    • Abstract: Publication date: July 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 7
      Author(s): Yu-guang ZHAO , Jia-tao ZHANG , Juan TAN , Bing-dong MA
      Grain refinement efficiency of electropulsing treatment (EPT) for metastable austenitic manganese steel was investigated. The mean grain size of original austenite is 300 μm. However, after EPT, the microstructure exhibits a bimodal grain size distribution, and nearly 70vol.% grains are less than 60 μm. The refined austenite results in ultrafine martensitic microstructure. The tensile strengths of refined austenitic and martensitic microstructures were improved from 495 to 670, and 794 to 900 MPa respectively. The fine grained materials possess better fracture toughness. The work-hardening capacity and wear resistance of the refined austenitic microstructure are improved. The reasonable mechanism of grain refinement is the combination of accelerating new phase nucleation and restraining the growth of neonatal austenitic grain during reverse transformation and rapid recrystallization induced by electropulsing.


      PubDate: 2014-07-28T03:11:42Z
       
  • Effect of Ball Scribing on Magnetic Shielding Efficiency of Grain-oriented
           Silicon Steel
    • Abstract: Publication date: July 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 7
      Author(s): Hao WANG , Chang-sheng LI , Rui-bin MEI , Gang HUO
      Magnetic shielding of grain-oriented silicon steel was investigated. Ball scribing with spacing of 2 to 16 mm was performed at peak flux densities of 8.0 mT to 1.3 T. Magnetic shielding efficiency was calculated, including absorption, reflection and inner multi-reflection shielding efficiencies. Magnetic shielding efficiency (MSE) increase ratios after different scribing spacing were compared, and thickness requirement to achieve absorption shielding of 50 dB was also calculated. The results show that magnetic shielding efficiencies of C711 and H668 silicon steels increase by 4.79 and 3.15 dB respectively after scribing of 16 mm. Before scribing, shielding efficiency of H668 steel was higher than that of C711 steel, while after scribing, both absorption and shielding efficiency gaps were largely abridged between C711 and H668 steels. Plate thickness of C711 steel could be reduced from 3.18 mm without scribing to 2.20 mm after scribing of 16 mm. There is no apparent thickness reduction at lower flux densities; while the peak flux density is above 0.3 T, the shielding effect becomes apparent, and the thickness could be reduced from 2.28 mm without scribing to 1.70 mm with scribing spacing of 16 mm. Magnetizing process and its effect on variation of magnetic shielding were also analyzed.


      PubDate: 2014-07-28T03:11:42Z
       
  • Effect of Indian Medium Coking Coal on Coke Quality in Non-recovery Stamp
           Charged Coke Oven
    • Abstract: Publication date: July 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 7
      Author(s): H.P. Tiwari , P.K. Banerjee , V.K. Saxena , S.K. Haldar
      The maximum possibility of utilizing the Indian coking coals and inferior grade coking coal for producing metallurgical coke through non-recovery stamp charging technology was investigated. Indian indigenous coals contained low percent of vitrinite (< 50%) and higher content of ash (> 15%) compared to imported coking coal. Therefore, the selection of appropriate proportion of different types of coals was a major challenge for coke makers. Coal blend selection criterion based on a single coefficient, named as composite coking potential (CCP), was developed. The use of increased proportion of semi-soft coal (crucible swelling number of 2.5) and high ash (≥ 15%) indigenous coal in the range of 20%–35% and 20%–65% respectively in the blends resulted in good quality of coke. Plant data of a non-recovery coke oven were used for developing and validating the model. The results showed that the coke strength after reaction (CSR) varied in the range of 63. 7%–67.7% and the M 40 value was between 81.8 and 89.3 in both the cases.


      PubDate: 2014-07-28T03:11:42Z
       
  • Parameters Affecting Energy Consumption for Producing High Carbon
           Ferromanganese in a Closed Submerged Arc Furnace
    • Abstract: Publication date: July 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 7
      Author(s): Azza Ahmed , Hossam Haifa , Mohamed K. El-Fawakhry , Hoda El-Faramawy , Mamdouh Eissa
      The power consumption is considered to be the most important factor affecting the production cost of ferromanganese alloy. Different parameters affecting the energy consumption for industrial production of high carbon ferromanganese HCFeMn were investigated in a closed submerged arc furnace. The analysis of industrial data revealed that the most energy-consumed factors were the direct reduction by solid carbon, Boudouard reaction, metal and slag formation, and decomposition of fluxing materials (limestone and dolomite). To reduce the energy consumption and minimize the energy losses in the production process of HCFeMn, it was recommended to use Mn blend with minimum Mn to Fe ratio of 6 and lower SiO2 content or higher basicity. The added coke must be adjusted according to the material balance to prevent the over-coke and to minimize the highly endothermic “Boudouard reaction”. In addition, it was recommended to work at basic slags with the ratio of (CaO+MgO) to SiO2 equal to 1.0–1.2 instead of much higher slag basicity. Furthermore, the mass losses had to be minimized through adjusting the handling and charging process and to take care of all metal produced.


      PubDate: 2014-07-28T03:11:42Z
       
  • Inclusion Distribution in Ingots Investigated by Dissection
    • Abstract: Publication date: July 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 7
      Author(s): Jian-hua LIU , Chang-ling ZHUANG , Xiao-ning CUI , Guo-xuan WANG , Quan-de GAO , Yan YANG
      Inclusion distribution in ingots was studied by dissection of a 16.8 t P12 ingot and a 5.0 t H13 ingot, with the analysis of T[O], original position statistic distribution analysis (OPA), metallographic microscope static analysis and small sample electrolysis. The results showed that the inclusions in ingots were uneven; a positive segregation area was found in the center and lower part of the ingot, while a negative segregation area was present in the central part of ingot top; inclusion segregation in a large size ingot was severer than that in a small one. A new concept, named inclusion segregation index, was put forward to quantify the segregation degree of inclusion. It was found that the segregation indexes drawn from T[O] analysis and OPA fit well, but they were different from those obtained by metallographic microscope static analysis and small sample electrolysis in the investigation of P12 ingot, which contained a higher sulfur content; while the segregation index drawn from T[O] analysis was close to that from metallographic microscope static analysis in the H13 ingot with a lower sulfur content.


      PubDate: 2014-07-28T03:11:42Z
       
  • Reduction of Pyrite Cinder Pellets Mixed with Coal Powder
    • Abstract: Publication date: July 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 7
      Author(s): Xiang-dong XING , Jian-liang ZHANG , Zhen-yang WANG , Ke-xin JIAO , Xing-le LIU , Shan REN
      Direct reduction of pyrite cinder in a rotary hearth furnace (RHF) was studied under the condition of laboratory simulation. Effects of reduction temperature, reduction time, molar ratio of carbon to oxygen, and CaO addition on metallization rate as well as compressive strength of the pellets after reduction were discussed. The results showed that the metallization rate and compressive strength were 93.9% and 2160 N per pellet respectively under the conditions of the reduction temperature of 1200 °C, the reduction time of 16 min, and the molar ratio of carbon to oxygen (x c/x o) of 1.0; adding 2.5% CaO was beneficial to sulfur enrichment in slag phase of pellet, and metallization rate increased slightly while compressive strength decreased.


      PubDate: 2014-07-28T03:11:42Z
       
  • Macro- and Microstructure Evolution of 5CrNiMo Steel Ingots during
           Electroslag Remelting Process
    • Abstract: Publication date: July 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 7
      Author(s): RAO Lei , ZHAO Jian-hua , ZHAO Zhan-xi , DING Gang , GENG Mao-peng
      A comprehensive mathematical model was established and used to simulate the macro- and microstructure evolution during the production process of 5CrNiMo steel ingot by electroslag remelting (ESR) method. Along the ingot height, the macrostructure distribution characteristics changed from vertical, fine columnar grains to tilted, coarse columnar grains, and this transformation process occurred at the very beginning of ESR. In the cross section of the ingot, there were three grain morphology regions and two grain type transition regions from the outside to the center of the ingot. These regions were the fine columnar grain region, columnar competitive growth transition region, coarse columnar grain region, columnar to equiaxed grain transition (CET) region, and coarse equiaxed grain region. The influence of the remelting rate on the macrostructure and microstructure was investigated using a series of experiments and simulations. The results showed that a low remelting rate could produce a small grain growth angle (GGA); the average secondary dendrite arm spacing (SDAS) firstly decreased and then increased as the remelting rate increased. An excessively high or low remelting rate can increase the GGA and average SDAS in ingots. Thus, the remelting rate should be controlled within a suitable range to reduce composition microsegregation and microshrinkage in the ingot to produce an ESR ingot with satisfactory hot forging performance.


      PubDate: 2014-07-28T03:11:42Z
       
  • Simplified Weighted Velocity Field for Prediction of Hot Strip Rolling
           Force by Taking into Account Flattening of Rolls
    • Abstract: Publication date: July 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 7
      Author(s): Dian-hua ZHANG , Jian-zhao CAO , Jiu-jing XU , Wen PENG , De-wen ZHAO
      The weighted velocity field was simplified for analysis of hot strip rolling. Using the field and GM (geometric midline) yield criterion, the deformation power, friction power and shear power were obtained respectively. Summing the partial power contributions, the total deformation power for strip rolling was presented. Then, by minimizing the power function, the rolling force was obtained; meanwhile, considering the effect of roll elastic flattening, iterative calculation of the roll radius was carried out until the radius was convergent. On-line data were compared with the calculated results to verify the model accuracy. It was indicated that the calculated rolling forces were basically in agreement with the measured ones since the maximum error was less than 10.0%. Moreover, the effects of various rolling conditions such as thickness reduction, friction factor and shape factor, upon separating force, location of neutral angle, and stress state coefficient were discussed systematically.


      PubDate: 2014-07-28T03:11:42Z
       
  • Gigacycle Fatigue Behavior of 1800 MPa Grade High Strength Spring Steel
           for Automobile Lightweight
    • Abstract: Publication date: June 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 6
      Author(s): Ji-ming ZHANG , Ling-kang JI , Dong-jie BAO , Yao-rong FENG , Shou-xin LI , Yu-qing WENG
      Gigacycle fatigue behavior of 60Si2CrVA high strength spring steel was investigated by ultrasonic fatigue test machine. Fatigue fractography was observed by scanning electron microscopy (SEM). Maximum inclusion sizes and fatigue strength in different volumes were estimated by statistics of extreme values (SEV) and generalized Pareto distribution (GPD) methods. The results showed that S-N curves of 60Si2CrVA spring steels for two rolling processes were not horizontal asymptotes but a gradient in a regime of 109 cycles, and traditional fatigue limits were eliminated. Surface machined topography and inclusions in steel were major factors that led to elimination of fatigue limit for 60Si2CrVA spring steel. The SEV and GPD methods could effectively predict size of the maximum inclusion and fatigue strength in different volumes of 60Si2CrVA spring steel. Predicted fatigue strength was in accordance with experimental results by ultrasonic fatigue testing.


      PubDate: 2014-06-14T21:27:49Z
       
  • Control over Mechanical Properties and Microstructure of BR1500HS
           Hot-stamped Parts
    • Abstract: Publication date: June 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 6
      Author(s): Bai-liang ZHUANG , Zhong-de SHAN , Chao JIANG , Xin-ya LI
      The hot-stamping processing parameters are of critical importance in transforming ultra-high-strength steel (UHSS) into high-quality parts, which were studied by mechanical properties tests, metallographic observations and calculation analysis method based on hot stamping experiments and numerical simulation technology, the mechanical properties, thickness, dimensional accuracy, and microstructure of the hot-formed parts are analyzed to determine the influence of different processing parameters for UHSS parts formed from BRI500HS. The results indicate that the quenching time had the most significant impact on the mechanical properties of the parts, and longer quenching time resulted in better mechanical properties. In addition, the pressing speed had a significant influence on the thickness of the formed parts, and the part-opening temperature had the most significant effect on the dimensional accuracy of the parts. And to get hot-stamped parts with excellent quality, the optimum process conditions should be set as heating temperature of 930 °C, soaking time of 4 min, stamping force of 7 MPa, pressing speed of 75 mm/s, quenching time of 15 s, and water-flow rate of 1.1 m/s.


      PubDate: 2014-06-14T21:27:49Z
       
  • Effects of Cu on Corrosion Resistance of Low Alloyed Steels in Acid
           Chloride Media
    • Abstract: Publication date: June 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 6
      Author(s): Hang SU , Xiao-bing LUO , Cai-fu YANG , Feng CHAI , Hao LI
      The corrosion resistance of two kinds of low alloyed steels was studied according to the test procedures for qualification of corrosion resistant steel for cargo oil tanks issued by International Maritime Organization. The results indicated that the addition of Cu improved the corrosion resistance of the NS-D36 steel to more than three times that of the conventional D36 steel in the strong acid solution containing chloride (10% NaCl, pH = 0. 85). The anodic polarization behavior of the copper-bearing steel was studied by polarization curves and electrochemical impedance spectroscopy (EIS), and alloying element Cu showed beneficial effects including an active potential range, low current density and high transfer resistance of electric charge. The rust layer was analyzed by scanning electron microscopy (SEM) and Auger electron spectroscopy (AES), and the results pointed out that the mechanism of copper's beneficial effects was based on the suppression of anodic dissolution by metallic copper re-deposition on the steel surface immersed in the strong acid chloride media.


      PubDate: 2014-06-14T21:27:49Z
       
  • Effect of Nb on Microstructure and Mechanical Properties in Non-magnetic
           High Manganese Steel
    • Abstract: Publication date: June 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 6
      Author(s): Jia-li CAO , Ai-min ZHAO , Ji-xiong LIU , Jian-guo HE , Ran DING
      Microstructure and mechanical properties of two kinds of non-magnetic high manganese steels with and without Nb addition which experienced the same rolling and heating treatment were investigated by means of scanning electron microscopy, electron back-scattered diffraction, transmission electron microscopy, X-ray diffraction and tensile test. It was found that the microstructure of the high manganese steel was refined by the Nb addition. Moreover, steel with Nb addition has a higher stacking fault energy which favors the deformation twinning. Twinning is the most important deformation mechanism in the Nb-bearing steel. Therefore, steel with Nb addition has much higher strength and higher plasticity. The product of tensile strength and total elongation exceeds 61.8 GPa · %. In addition, steel with Nb addition also has excellent non-magnetic property.


      PubDate: 2014-06-14T21:27:49Z
       
  • Quantitative Research on Dissolving of Nb in High Nb Microalloyed Steels
           during Reheating
    • Abstract: Publication date: June 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 6
      Author(s): Ya-bin CAO , Fu-ren XIAO , Gui-ying QIAO , Bo LIAO
      The accurate prediction of soluble Nb content during reheating is helpful for the design of chemical composition and reheating parameters for Nb-containing steels. The dissolution behavior of Nb in high Nb microalloyed steels was investigated. The results show that Nb does not entirely dissolve for high Nb microalloyed steels containing Ti after holding at 1300 °C for 3 h. The soluble Nb content increases with the decrease of C content and/or the increase of Nb content in steels. Moreover, an expression has been established to describe the amount evolution of soluble Nb in high Nb microalloyed steels during reheating and the validity of this expression has also been verified by experiment.


      PubDate: 2014-06-14T21:27:49Z
       
  • Intercritical Rolling Induced Ultrafine Lamellar Structure and Enhanced
           Mechanical Properties of Medium-Mn Steel
    • Abstract: Publication date: May 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 5
      Author(s): Wei ZHAN , Li-qiang CAO , Jun HU , Wen-quan CAO , Jian LI , Han DONG
      The medium-Mn steel with ferrite and austenite structure was rolled in the intercritical region down to different rolling reduction. The microstructure and mechanical properties of the rolled steels were investigated by scanning electron microscopy, transmission electron microscopy, X-ray diffraction and tensile tests. It was found that the ferrite and austenite structure gradually evolved into an ultrafine structure from the random directional lath structure to lamellar structure with lath longitudinal direction parallel to the rolling direction with increasing rolling strain. It was found that the thickness of the laths was gradually refined with increasing rolling strain. The lath thickness is about 0. 15 μm stored with high density dislocations and the austenite volume fraction of the steel is about 24% after 80% rolling reduction. Furthermore, it was interesting to find that yield strength, tensile strength and total elongation of the 80% rolled medium-Mn steel are about 1000 MPa, 1250 MPa and 24%, respectively, demonstrating an excellent combination of the strength and ductility. Based on the microstructure examination, it was proposed that the grain refinement of the medium-Mn steels could be attributed to the duplex structure and the low rolling temperature. Analysis of the relationship between the microstructure and the mechanical properties indicated that the high yield strength mainly resulted from the ultrafine grain size and the high density dislocation, but the improved ductility may be attributed to the large fractions of austenite retained after intercritical rolling.


      PubDate: 2014-06-14T21:27:49Z
       
  • Self-lubricating CrVN Coating Strengthened via Multilayering with VN
    • Abstract: Publication date: May 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 5
      Author(s): Yue-xiu QIU , Bo LI , Jyh-wei LEE , Dong-liang ZHAO
      To improve the mechanical properties of self-lubricating chromium vanadium nitride (CrVN) coatings, vanadium nitride (VN) is combined with CrVN to form multilayered CrVN/VN coatings through an in-line magnetron sputtering system. The strengthening effect of the period thickness on the mechanical and tribological properties is studied. X-ray diffractometer, low-angle X-ray reflectivity, scanning electron microscopy, atomic force microscopy, electron probe micro-analyzer and X-ray photoelectron spectroscopy are employed to characterize the microstructures and chemical composition. Nanoindentation and ball-on-disc tribo-tester are used in characterization of the mechanical and tribological properties. The CrVN/VN multilayer coatings demonstrate good lubrication property with coefficient of friction down to 0. 23. Multilayering with VN, the hardness of CrVN jumps to 27. 6 GPa with period thickness of 6 nm, which has an improvement of 5. 1 GPa compared with that of 22. 5 GPa from rule-of-mixture.


      PubDate: 2014-06-14T21:27:49Z
       
  • Microstructure and Mechanical Properties of GMAW Weld Metal of 890 MPa
           Class Steel
    • Abstract: Publication date: May 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 5
      Author(s): Yun PENG , Xing-na PENG , Xiao-mu ZHANG , Zhi-ling TIAN , Tao WANG
      The relationship between microstructure and mechanical properties of gas metal arc weld metal with strength over 890 MPa is discussed. The microstructure of the weld metals is characterized with OM, SEM, TEM and EBSD. The microstructure of the weld metals is mainly composed of martensite and bainite. Experimental results show that the microstructure with predominant fine lath bainite possesses good toughness of 77 J, while its yield strength is less than 800 MPa. The microstructure of coarse lath martensite and bainite has the lowest toughness of 43 J and its yield strength is 820 MPa. The mixed microstructure with fine martensite, bainite and retained austenite films bears good combination of toughness and yield strength (62 J and 880 MPa, respectively). It is concluded that fine effective grain size and ductile phase of austenite films are two main factors to achieve good mechanical properties.


      PubDate: 2014-06-14T21:27:49Z
       
  • Effect of Heat Treatment on Structure and Wear Resistance of High Chromium
           Cast Steel Containing Boron
    • Abstract: Publication date: May 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 5
      Author(s): Qi-hong CEN , Hai-bin ZHANG , Han-guang FU
      The microstructure, mechanical properties and wear resistance of high chromium cast steel containing boron after different heat treatments were studied by means of the optical microscopy (OM), the scanning electron microscopy (SEM), X-ray diffraction (XRD), hardness, impact toughness, tensile and pin-on-disc abrasion tests. The results show that as-cast microstructures of boron-free high chromium steel consist of martensite and a few (Cr, Fe)7C3 carbide, and the macro-hardness of boron-free high chromium steel is 55–57 HRC. After 0.5 mass% B was added into high chromium cast steel, as-cast structure transforms into eutectic (Fe, Cr)2B, (Cr, Fe)7 (C, B)3 and martensite, and the macro-hardness reaches 58–60 HRC. High temperature quenching leads to the disconnection and isolated distribution of boride, and there are many (Cr, Fe)23 (C, B)6 precipitated phases in the quenching structure. Quenching from 1050 °C, high chromium steel obtained the highest hardness, and the hardness of high chromium cast steel containing boron is higher than that of boron-free high chromium steel. The change of quenching temperature has no obvious effect on impact toughness of high chromium steel, and the increase of quenching temperature leads to tensile strength having an increasing tendency. At the same quenching temperature, the wear resistance of high chromium cast steel containing boron is more excellent than that of boron-free high chromium steel. High chromium cast steel guide containing boron has good performance while using in steel bar mill.


      PubDate: 2014-06-14T21:27:49Z
       
  • Constitutive Modeling for Elevated Temperature Flow Behavior of
           30Cr2Ni4MoV Ultra-super-critical Rotor Steel
    • Abstract: Publication date: May 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 5
      Author(s): Fei CHEN , Fa-cai REN , Zhen-shan CUI , Xin-min LAI
      In order to perform numerical simulation of forging and determine the hot deformation processing parameters for 30Cr2Ni4MoV steel, the compressive deformation behaviors of 30Cr2Ni4MoV steel were investigated at the temperatures from 970 to 1270 °C and strain rates from 0. 001 to 0. 1 s−1 on a Gleeble-3500 thermo-mechanical simulator. The flow stress constitutive equations of the work hardening-dynamical recovery period and dynamical recrys-tallization period were established for 30Cr2Ni4MoV steel. The stress-strain curves of 30Cr2Ni4MoV steel predicted by the proposed model well agreed with experimental results, which confirmed that the proposed equations can be used to determine the hot deformation processing parameters for 30Cr2Ni4MoV steel.


      PubDate: 2014-06-14T21:27:49Z
       
  • Microstructure and Mechanical Properties of TRIP Steel with Annealed
           Martensite
    • Abstract: Publication date: May 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 5
      Author(s): Wei DING , Zhi-hua GONG , Bao-feng WANG , Di TANG , Hai-tao JIANG
      The microstructure and mechanical properties of cold rolled TRIP steel containing C 0.2, Si 0.5, Mn 1.5, Al 1. 3, and Nb+V 0. 13 (mass%) with annealed martensite (TAM steel) were investigated using optical microscopy, field emission gun scanning electronic microscope (FEG SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and mechanical testing. The microstructure of the TAM steel mainly consisted of polygonal ferrite, bainite, annealed martensite and retained austenite. The martensite after annealing did not spheroidize, which consisted of annealed lath martensite structure and interlath second phase. Compared with the traditional TRIP steel with polygonal ferrite matrix (TPF steel), the TAM steel has more excellent elongation rate over 32%. The TAM steel also has better strain hardening behavior than the TPF steel. The excellent elongation and strain hardening behavior of TAM steel result from high retained austenite stability of the TAM steel, which is attributed to its fine distribution and medium strength ratio of second phase to matrix.


      PubDate: 2014-06-14T21:27:49Z
       
  • Preparation of Nanoscale Sm2Co17 Flakes by Ball Milling in Magnetic Field
    • Abstract: Publication date: May 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 5
      Author(s): Xiao-dong LI , Ying CHANG , Zhi-yong WEI , Guang-yi CHEN , Ming-gang ZHU , Ling WENG
      A new preparation method of Sm2Co17 nanoflakes was investigated. Hard magnetic Sm2Co17 nanoflakes with thickness of 20–100 nm were obtained by milling in heptane and oleic acid under a magnetic field of 1. 5 T for 0.5–20 h. It was shown that higher anisotropic magnetic properties would be induced by the flake-shape anisotropy when the prepared Sm2Co17 particles are milled with a magnetic field. The magnetic anisotropy of flakes after being aligned under the magnetic field of 1. 5 T could be further enhanced, and the value of (BH)m was 128 kJ · m−3. Both anisotropy and properties are better than those of the nano-particles milled without a magnetic field.


      PubDate: 2014-06-14T21:27:49Z
       
  • Effects of Heat Treatment Process Parameters on Microstructure and
           Mechanical Properties of DP440 Cold Rolled Strip
    • Abstract: Publication date: May 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 5
      Author(s): Gang HUO , Yi-ming CEN , Zhen-xing LI , Guo-dong LI , Chang-sheng LI
      In order to optimize the production process, improve the production efficiency and accelerate the development and application of the domestic dual-phase steel, the effects of heat treatment process parameters on micro-structure and mechanical properties of DP440 cold rolled strip were studied by the CAS-300 simulated continuous annealing equipment. When the heating rate increased from 5 to 100 °C/s, both the tensile strength and yield strength increased because of the decreased grain size. When the intercritical annealing temperature increased from 780 to 850 °C, the martensite content decreased so that the tensile strength decreased first, then increased, and the yield strength increased. When the rapid cooling rate increased from 25 to 100 °C/s, because the martensite content increased, the tensile strength increased, while the yield strength decreased. When the overaging temperature increased from 260 to 400 °C, the tensile strength decreased, while the yield strength increased. When the overaging time increased from 240 to 480 s, the tensile strength decreased a little, while the yield strength increased a little.


      PubDate: 2014-06-14T21:27:49Z
       
  • Broadside Compensation Rolling Model for Plan View Pattern Control in Wide
           and Heavy Plate Rolling Process
    • Abstract: Publication date: May 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 5
      Author(s): Jin-hua RUAN , Li-wen ZHANG , Sen-dong GU , Jian-lin ZHANG , Wen-bin HE , Shao-hui CHEN
      On the basis of a 5 m plate mill, a 3D rigid-plastic finite element (FE) model was developed to investigate changes of plate plan view patterns during hot rolling process. By analyzing the simulation results of conventional rolling processes, it was found that the plate plan view pattern was closely related to broadside rolling ratio. Then, the prediction models for plate plan view patterns were formulated by nonlinear regressive analysis of the simulation results and modified for high accuracy. Based on these models, the broadside compensation rolling method performing at the last pass of broadside rolling phase was designed to decrease plate end crops. Comparing the plate plan view patterns with and without broadside compensation rolling, reduced plate end crops indicate that the broadside compensation rolling model is effective for plate plan view pattern control.


      PubDate: 2014-06-14T21:27:49Z
       
  • Three-phase Fluid Numerical Simulation and Water Modeling Experiment of
           Supersonic Oxygen Jet Impingement on Molten Bath in EAF
    • Abstract: Publication date: June 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 6
      Author(s): Shao-chun CHEN , Rong ZHU , Jing-she LI , Chun-lai HE , Ming LÜ
      By means of the computational fluid dynamics software Fluent 6. 3, a mathematical model of three-dimensional three-phase fluid flow field in the molten bath of electric arc furnace (EAF) with side accessorial oxygen lances was developed to study the transient phenomena of oxygen jet impingement on the molten steel and the molten slag. The water modeling experiment was carried out to verify the simulation results. The impingement of the supersonic oxygen jet caused impact dent on the molten steel surface accordingly. The area of impact dent changed almost in linear relationship to flow rate of oxygen jet, which can be expressed by a deduced mathematical equation. And the relationship between the impact force of oxygen jet and the correspondingly formed apparent static pressure on molten bath was obtained, which was in linear relationship and a direct proportion, and can also be expressed by a deduced mathematical equation.


      PubDate: 2014-06-14T21:27:49Z
       
  • Removal Mechanism of Zn, Pb and Alkalis from Metallurgical Dusts in Direct
           Reduction Process
    • Abstract: Publication date: May 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 5
      Author(s): Xue-feng SHE , Jing-song WANG , Guang WANG , Qing-guo XUE , Xin-xin ZHANG
      The high-temperature tube furnace was applied to simulate the rotary hearth furnace (RHF) for the direct reduction of zinc-bearing dusts from steel plants. The removal mechanism of Zn, Pb and alkalis from cold bonded briquettes made by mixing metallurgical wastes, such as dust from bag house filter, OG sludge, fine converter ash and dust from the third electric field precipitator of the sinter strand, in various proportions was investigated. More than 70% of metallization rate, more than 95% of zinc removal rate, 80% of lead removal, as well as more than 80% of K and Na removal rates were achieved for the briquettes kept at 1473–1603 K for 15 min during the direct reduction process respectively. The soot generated in the direct reduction process was studied by chromatography, X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results suggested that the main phases of the soot were ZnO, KCl, NaCl and 4ZnO · ZnCl2 · 5H2O. Furthermore, the content of Zn reached 64.2%, which could be used as secondary resources for zinc making. It was concluded that KCl and NaCl in secondary dust resulted from the volatilization from the briquettes, whilst ZnO and PbO were produced by the oxidation of Zn or lead vapour from briquettes by direct reduction.


      PubDate: 2014-06-14T21:27:49Z
       
  • Separation and Recovery of Phosphorus from P-bearing Steelmaking Slag
    • Abstract: Publication date: May 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 5
      Author(s): Lu LIN , Yan-ping BAO , Min WANG , Wei JIANG , Han-mei ZHOU
      In order to recycle the phosphorus from P-bearing steelmaking slag, the influences of magnetic field intensities, slag particle sizes and slag compositions were investigated by magnetic separation experiments. SiO2, Al2O3 and TiO2 melting modification of converter slag was made respectively and phosphorus-rich phase was extracted by magnetic separation. The results show that MgO, MnO, Na2O and CaF2 have little effect on the phosphorus recovery, whereas the addition of SiO2, Al2O3, and TiO2 has great effect on phosphorus enrichment in slag and magnetic separation. With adding the reagent of SiO2, Al2O3 and TiO2, recycled non-magnetic substances are increased obviously and P2O5 content in non-magnetic substances and phosphorus recovery rate are also increased. The phosphorus recovery rates of modified slag No. 8 (SiO2 modification), slag No. 10 (Al2O3 modification) and slag No. 11 (TiO2 modification) are 84. 75%, 82. 16% and 74. 46%, respectively. Then, most of phosphorus was recycled.


      PubDate: 2014-06-14T21:27:49Z
       
  • Effects of Mg Addition on Inclusions Formation and Resultant
           Solidification Structure Changes of Ti-stabilized Ultra-pure Ferritic
           Stainless Steel
    • Abstract: Publication date: June 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 6
      Author(s): Ying-tie XU , Zhao-ping CHEN , Mao-tao GONG , Da SHU , Yue-mei TIAN , Xiang-qian YUAN
      The effects of Mg addition on the formation of nonmetallic inclusions and solidification structure of Ti-stabilized ultra-pure ferritic stainless steels were investigated by experimentally casting ingots with different compositions. Thermodynamic analyses on the formation of complex inclusions after adding Mg into steels were carried out combined with the scanning electron microscopy-energy dispersive spectrometry (SEM-EDS) analysis. And the EDS analysis showed that in steel samples with Mg addition, a new spinel crystal phase combined with Al2O3-TiO x formed. It was also found that after Mg addition, the proportions of equiaxed grain zone of 409L, 4003, 439 and 443NT steels increased from 10.2%, 21.8%, 13.4% and 18.6% to 84.3%, 92.3%, 91.1% and 100.0%, respectively. Since the planar disregistry between spinel and TiN is 5.1%, spinel could promote the precipitation of TiN and increase the number density of TiN inclusions in steel melts. The mechanism of solidification structure refinement after adding Mg into steels supposed that the complex inclusions of spinel and TiN in high number density enhanced columnar-to-equiaxed transition, since the planer disregistry between δ phase and spinel is 1.4%.


      PubDate: 2014-06-14T21:27:49Z
       
  • Corrosion Resistance and Semiconducting Properties of Passive Films Formed
           
    • Abstract: Publication date: June 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 6
      Author(s): De-ning ZOU , Rong LIU , Jiao LI , Wei ZHANG , Duo WANG , Ying HAN
      The semiconducting properties of passive films grown on 00Cr13Ni5Mo2 supermartensitic stainless steel were investigated in comparison with conventional 2Cr13 martensitic stainless steel. Cyclic voltammetry and electrochemical impedance spectroscopy (EIS) were used for the studies. 00Cr13Ni5Mo2 steel exhibited a good corrosion resistance performance, attributing to its passive capability. The results of Mott-Schottky analysis demonstrated n-type semiconductors for the passive films with doping densities of about 1O20 − 1021 cm−3, and the thickness of spacecharge layers was also calculated. The experimental results confirmed that Mo plays an important role in improving the corrosion resistance of 00Cr13Ni5Mo2 steel due to its impact on the doping density.


      PubDate: 2014-06-14T21:27:49Z
       
  • An On-line Finite Element Temperature Field Model for Plate Ultra Fast
           Cooling Process
    • Abstract: Publication date: May 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 5
      Author(s): Xiao-lin CHEN , Guo-dong WANG , Yong TIAN , Bing-xing WANG , Guo YUAN , Zhao-dong WANG
      Taking the element specific-heat interpolation function into account, a one-dimensional (1-D) finite element temperature field model for the on-line control of the ultra fast cooling process was developed based on the heat transfer theory. This 1-D model was successfully implemented in one 4300 mm plate production line. To improve the calculation accuracy of this model, the temperature-dependent material properties inside an element were considered during the modeling process. Furthermore, in order to satisfy the real-time requirements of the on-line model, the variable bandwidth storage method and the Cholesky decomposition method were used in the programming to storage the data and carry out the numerical solution. The on-line application of the proposed model indicated that the deviation between the calculated cooling stop temperature and the measured one was less than ±15 °C.


      PubDate: 2014-06-14T21:27:49Z
       
  • Application and Experiment on the Least-action Principle of Explosive
           Welding of Stainless Steel/Steel
    • Abstract: Publication date: June 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 6
      Author(s): Chang-gen SHI , Yu WANG , Si-jing LI , Jun YOU
      In nature, many physical phenomena follow the least-action principle, which is also abided by the course of explosive welding of stainless steel/steel. The optimal welding interface can be obtained with the least explosive charge by theoretical analysis and interface test. The bonding energy can be acknowledged as the “action” in explosive welding. To minimize the bonding energy, these rules must be followed such as the lower limit of explosive charge, the upper limit of span and the explosive of critical explosion velocity. The principle of least-action is achieved in the course of explosive welding, and the interface will be optimum.


      PubDate: 2014-06-14T21:27:49Z
       
  • Comprehensive Evaluation of OxyCup Process for Steelmaking Dust Treatment
           Based on Calculation of Mass Balance and Heat Balance
    • Abstract: Publication date: June 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 6
      Author(s): Ke-jiang LI , Jian-liang ZHANG , Zheng-jian LIU , Rui MAO , Tian-jun YANG
      Through the mass balance and thermal balance calculation for a typical OxyCup (or OxiCup) furnace process featuring a capacity of 380 kt/a of steel plant residuals, the material flow and thermal flow diagrams were firstly obtained. Then, the performance of the main fuel in the OxyCup process, i.e. coke and carbon dust, was analyzed, and the results indicated that coke was mainly used as the stock column skeleton for the furnace and exothermal agent with a weak reduction ability; whereas carbon dust was mixed in the C-brick to reduce the iron oxide. In addition, the comparison between OxyCup process and traditional blast furnace process indicated that the reduction and melting processes in the OxyCup process were relatively isolated, while in the traditional blast furnace process, they were mixed with each other in the high temperature zone. Moreover, oxidizing atmosphere is necessary in part of the OxyCup furnaces to ensure the complete combustion of part of the coke, while only reducing atmosphere is allowed in traditional blast furnaces. Finally, it was confirmed that oxygen enrichment can make a remarkable increase of the energy income and high temperature blast makes only a small contribution to energy income as the energy from the combustion of carbon takes up nearly 90% of the total income.


      PubDate: 2014-06-14T21:27:49Z
       
  • Heat Transfer and Central Segregation of Continuously Cast High Carbon
           Steel Billet
    • Abstract: Publication date: June 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 6
      Author(s): Wang SU , Wei-ling WANG , Sen LUO , Dong-bin JIANG , Miao-yong ZHU
      A numerical model of heat transfer was developed to investigate the heat transfer of continuously cast billet with the aid of surface temperature tests by ThermaCAM™ researcher and nail shooting experiments. The effects of secondary cooling practice and casting speed on the solidification process and central segregation of carbon were investigated as well with the actual central segregation tests. The results show that the surface center and billet center temperatures exhibit a different pattern during solidification, and the solidified shell thickness is presented as an “S” type. With the increase of secondary cooling intensity and the decrease of casting speed, the end points of the solidus line and the liquidus line move forward, and the central segregation level of carbon decreases. The optimal casting condition is suggested for continuously cast high carbon billet with F-EMS (final electromagnetic stirring).


      PubDate: 2014-06-14T21:27:49Z
       
  • Cloud Neural Fuzzy PID Hybrid Integrated Algorithm of Flatness Control
    • Abstract: Publication date: June 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 6
      Author(s): Chun-yu JIA , Tao BAI , Xiu-ying SHAN , Fa-jun CUI , Sheng-jie XU
      In connection with the characteristics of multi-disturbance and nonlinearity of a system for flatness control in cold rolling process, a new intelligent PID control algorithm was proposed based on a cloud model, neural network and fuzzy integration. By indeterminacy artificial intelligence, the problem of fixing the membership functions of input variables and fuzzy rules was solved in an actual fuzzy system and the nonlinear mapping between variables was implemented by neural network. The algorithm has the adaptive learning ability of neural network and the indeterminacy of a cloud model in processing knowledge, which makes the fuzzy system have more persuasion in the process of knowledge inference, realizing the online adaptive regulation of PID parameters and avoiding the defects of the traditional PID controller. Simulation results show that the algorithm is simple, fast and robust with good control performance and application value.


      PubDate: 2014-06-14T21:27:49Z
       
  • Effects of Offline Relaxation Quenching on Microstructure and Mechanical
           Properties of a Newly Designed High Performance Steel
    • Abstract: Publication date: April 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 4
      Author(s): Wen-zhen XIA , Xian-ming ZHAO , Xiao-ming ZHANG , Di WU
      The newly designed high performance tested steel was prepared by the process of vacuum induction furnace smelting and forging. According to the ideas of online relaxation and quenching-intercritical quenching-tempering (Q-L-T) process, effects of offline relaxation process on microstructure and mechanical properties of the tested steel were investigated. Offline relaxation process was simulated using the MMS-300 thermal simulation testing apparatus and heat treating furnace. The results show that the microstructures are composed of bainite and martensite when the specimens are quenched in the austenite region. Once the specimens are air-cooled into the dual phase region, ferrite and granular bainite start to form. In the relaxation process, fine Nb(C, N) carbonitrides are precipitated first and then grow and coarsen. The microstructure is affected by process and determines mechanical properties. The Vickers hardness and yield strength (YS) first rise then fall when the relaxation temperature drops in austenite region, and then decline dramatically in dual phase region. When the relaxation time is 20 s, the tensile strength reaches the peak (1034 MPa), and at that time YS is 872 MPa, longation is 17. 7% and Charpy V-notch impact energy is 171 J at — 20 °C. When the relaxation time increases to 100 s, the yield and tensile strengths are 750 and 934 MPa respectively, elongation is 18. 6% and Charpy V-notch impact energy is 165 J at – 20 °C.


      PubDate: 2014-04-29T13:50:10Z
       
  • Hot Ductility of Ti-V Bearing Microalloyed Steel in Continuous Casting
    • Abstract: Publication date: April 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 4
      Author(s): Yan-hui SUN , Ya-nan ZENG , Kai-ke CAI
      Hot ductility of Ti-V bearing steel was studied by theoretical calculation and thermal simulation experiment. Meanwhile, microsegregation and precipitates were analyzed. The results showed that elements S, Ti and O were enriched at the grain boundaries, while the hot ductility was deteriorated by inclusions of (Fe, Mn, Si, Al) (S, O) in the interdendritic region. At the temperature of 1100 °C, large TiN particles had little effect on hot ductility. In the temperature range from 975 to 925 °C, reduction of area (R. A) declined rapidly from 81. 88% to 63. 16% with the size of particles decreasing from 40 to 20 nm and quantity increasing from 1. 4 to 11. 9 μm 2, respectively. In the temperature range from 875 to 825 °C, R. A reduced unobviously from 35. 14% to 28. 6% with ferric films thickening gradually. The critical stress, 88. 79 MPa, was equal to tensile strength at 825 °C. Intergranular fracture was easy to occur with higher critical stress below 825 °C


      PubDate: 2014-04-29T13:50:10Z
       
  • Effects of Sulphate-reducing Bacteria on Corrosion Behaviour of 2205
           Duplex Stainless Steel
    • Abstract: Publication date: April 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 4
      Author(s): Cheng-hao LIANG , Hua WANG , Nai-bao HUANG
      The effects of sulphate-reducing bacteria (SRB) on the 2205 duplex stainless steel in the sea water and oil industry environments were studied by electrochemical impedance spectroscopy (EIS), potentiodynamic polarization and microorganism analysis. The results showed that the detected SRB was the non-spore bacillus of about 0. 8 μm × (1.8 — 2.2) μm in size and the content of S was about 7.59% in the corrosion products. SRB contributed to the corrosion evolution which caused the corrosion failure of 2205 duplex stainless steel pipe in the liquid hydrocarbon cooler. During the corrosion process, the produced H2S could significantly influence the anodic process and finally accelerate the corrosion. SEM observation indicated that the distribution of SRB on the surface of 2205 duplex stainless steel was nonuniform. X-ray photoelectron spectroscopy analysis revealed that the surface film was composed of Cr2O3, MoO3, FeS, FeS2, Fe(OH)2 and FeO after immersing the sample in the SRB medium for 14 d.


      PubDate: 2014-04-29T13:50:10Z
       
  • Strain Hardening of a Layered and Nanostructured AISI 304 Stainless Steel
    • Abstract: Publication date: April 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 4
      Author(s): Yan-quan JIA , Yong-li LIANG , Ai-ying CHEN , Deng PAN
      In order to improve the low ductility of nanostructured materials, a layered and nanostructured (LN) 304 SS (stainless steel) is prepared from warm co-rolled 304 SS pre-treated by surface mechanical attrition treatment. The microstructure and mechanical properties, as well as strain hardening, are analyzed in details. The LN steels exhibit both high strength and large ductility resulting from good strain hardening behaviors. The strain hardening can be subdivided into two stages, which involves a multiple cracking along interlaminar at the first stage and a strain-induced martensite (SIM) transformation at the second stage. The SIM transformation of nanocrystallines and ultrafine grains induces a larger work hardening exponent by the formation of nanoscaled martensite phase. The effect of grain size on the transformation dynamics is discussed.


      PubDate: 2014-04-29T13:50:10Z
       
  • Influence of Finishing Cooling Temperature and Holding Time on
           Nanometer-size Carbide of Nb-Ti Microalloyed Steel
    • Abstract: Publication date: April 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 4
      Author(s): Hai-long YI , Yang XU , Ming-xue SUN , Zhen-yu LIU , Guo-dong WANG
      The nanometer-size carbides formed in ferrite matrix of Nb-Ti microalloyed steel at different finishing cooling temperatures and holding time have been investigated. The characteristics of nanometer-size carbides in ferrite were observed by transmission electron microscopy, and mechanical properties of ferrite were detected by a nano-hardness tester. The results showed that interphase precipitation and diffusion precipitation were observed at different finishing cooling temperatures, and the interphase precipitation was planar and curved. Sheet spacing of interphase precipitation increased with the increase of finishing cooling temperature and changed a little when holding for 50 — 1000 s. Interphase precipitation shows higher nano-hardness at 640 °C compared with diffusion precipitation at 600 °C, and the contribution of interphase precipitation to the mechanical properties of ferrite was larger than that of diffusion precipitation.


      PubDate: 2014-04-29T13:50:10Z
       
  • Evolution of Surface Transversal Crack in Intermediate Slabs during Hot
           Rolling Deformation
    • Abstract: Publication date: April 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 4
      Author(s): Yan-zhao LUO , Jiong-ming ZHANG , Qiang LIU , Mao-kang LI , Yi-tong HAN , Yi-fei CAO
      In the continuous casting of steels, surface transversal cracks are often found. These defects may severely influence the final quality of the products. The evolution of transversal V-shaped cracks with different depth on the surface of a continuously cast steel slab during hot rolling was studied. The artificial V-shaped cracks were made on the surface. The rolling process parameters from an industrial rolling mill have been used as a reference. The specimens of rolled workpiece in intermediate slabs were obtained after different rolling passes. The morphology of surface crack and microstructure evolution in the rolling process were investigated by optical microscopy. The results show that the depth of surface transversal crack gradually decreased with the increase of rolling passes. The grain size of ferrite and pearlite on the sample surface also gradually reduced. The microstructures around cracks with the different depth are almost identical, without direct correlation with the initial crack depth.


      PubDate: 2014-04-29T13:50:10Z
       
  • Constitutive Model for F45V Microalloyed Forging Steel at High Temperature
    • Abstract: Publication date: April 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 4
      Author(s): Jin WANG , Wen-long MA , Zhong CHU , Qi ZHANG
      Isothermal hot compression experiments of F45V, a microalloyed steel, were performed on a Gleeble-1500 thermo-mechanical simulator at temperatures of 950 — 1200 °C and strain rate of 0. 01 — 10 s 1 . Based on the experimental flow stress curves, a constitutive model that was expressed by the hyperbolic laws in an Arrhenius-type equation was established, and the material parameters of the model were expressed as 6th order polynomial form of strain. Standard statistical parameters such as correlation coefficient and average absolute relative error were employed to quantify the predictability of the model. They were found to be 0. 995 and 4. 34% respectively. The results show that the established constitutive model can predict the magnitude and tendency of flow stress with the increase of deformation accurately, and can be used for the numerical simulation of hot forging process of the F45V steel.


      PubDate: 2014-04-29T13:50:10Z
       
  • Analysis of Fishscaling Resistance of Low Carbon Heavy Plate Steels
    • Abstract: Publication date: April 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 4
      Author(s): Ai-wen ZHANG , Zheng-yi JIANG , Dong-bin WEI , Si-hai JIAO , Chun XU
      The precipitates and hydrogen permeation behavior in three kinds of hot rolled low carbon heavy plate steels for enameling were analyzed; then, both sides of the steels were enameled. The experimental results show that a large amount of coarse Ti4C2S2 and fine Ti(C, N) particles exist in the optimized Ti-bearing steel, quite a lot of fine Ti(C, N) particles exist in the optimized carbon steel, but only a little bit fine Ti(C, N) particles exist in the carbon steel. The fishscaling resistance of the steels can be correlated to the effective hydrogen diffusion coefficient, and a model of correlation between the effective hydrogen diffusion coefficient and the volume fraction of the precipitates was established and verified. The effective hydrogen diffusion coefficient should be lower than 3. 96 × 10 6 cm2/s to avoid fishscaling in heavy plate steels.


      PubDate: 2014-04-29T13:50:10Z
       
  • Carbothermic Reduction of Zinc and Iron Oxides in Electric Arc Furnace
           Dust
    • Abstract: Publication date: April 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 4
      Author(s): Hui-ning ZHANG , Jian-li LI , An-jun XU , Qi-xing YANG , Dong-feng HE , Nai-yuan TIAN
      The reduction of zinc and iron oxides from electric arc furnace dust (EAFD) by carbon was investigated at temperatures between 800 and 1300 °C. The analytic technique employed includes chemical analysis, X-ray fluorescence spectroscopy (XRF), X-ray powder diffraction (XRD), scanning electron microscopy (SEM) equipped with X-ray energy dispersive spectrometry (EDS), and thermodynamic database FactSage 6. 2. It was found that the reduction of zinc and iron oxides depends largely on Boudouad reaction. At 900 °C, zinc exists in tested samples as ZnO, which is reduced in the temperature range of 1000 — 1100 °C. At 1100 °C, 99. 11% of the zinc is evaporated. The metallization ratio of Fe is 79. 19% at 1300 °C, as the content of Fe2+ is still 9. 40%. A higher temperature is thus required for a higher reduction degree of Fe oxides by solid or gaseous carbon.


      PubDate: 2014-04-29T13:50:10Z
       
  • A New Simplified Zonal Method for Furnace Thermal Radiation Calculation
           Based on Imaginary Planes
    • Abstract: Publication date: April 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 4
      Author(s): Wei-jun ZHANG , Zhi YI , Hai-geng CHEN
      When solving the complex radiative heat transfer problems in reheating furnaces, there are a number of difficulties with the traditional zonal methods. To circumvent these difficulties, a new simplified method was proposed, which employed imaginary planes, referred to as the imaginary plane model. With the new model, crown wall reduction process was simplified. Therefore, every model zone could be treated as a closed square cavity. It could also solve the problem of radiative blocking in industrial furnaces more effectively. Besides, the new imaginary plane based model may lead to a problem that the denominator was zero. This problem was solved by transforming the expressions of reflex heat flux in the model. The model was capable of dealing with the systems that included black surfaces. The model was validated by considering the heat transfer in a reheating furnace where the temperature fields in the furnace chamber (including the steel, wall and gas) were obtained. A detailed comparison was made between the simulation and the black box experiment. The results show that the new model developed was valid and accurate.


      PubDate: 2014-04-29T13:50:10Z
       
  • Computational Insights into Interactions between Ca Species and
           α-Fe2O3 (0 0 1)
    • Abstract: Publication date: April 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 4
      Author(s): Yan-qin SUN , Qing LÜ , Xin-yu WAN , Shu-hui ZHANG , Jiong-ming ZHANG
      CaCl2 can be sprayed onto sinter surface, which can improve the low temperature reduction degradation index (RDI+3.15) of sinter. This has been recognized; however, there are various opinions on the inhibition mechanism of it. At the same time, the corrosion of Cl element on equipment is very serious. First-principle calculations based on density functional theory were performed to investigate the binding mechanisms of calcium species on a α-Fe2O3 (0 0 1) surface. This is crucial in demonstrating the role of the CaCl2 on improving the low temperature reduction degradation index. It has been determined that Cl could greatly increase the adsorption of the vacuum layer for the Ca/Fe2O3 system and the relaxation produced by adsorption made bond length decrease, bond energies increase and structure compact. Those are the main reasons that inhibiting the reduction disintegration of sinter.


      PubDate: 2014-04-29T13:50:10Z
       
  • Mathematical Modeling of Multi-sized Argon Gas Bubbles Motion and Its
           Impact on Melt Flow in Continuous Casting Mold of Steel
    • Abstract: Publication date: April 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 4
      Author(s): Chong-lin LIU , Zhi-guo LUO , Tao ZHANG , Shen DENG , Nan WANG , Zong-shu ZOU
      The 3D turbulence k-ε model flow of the steel melt (continuous phase) and the trajectories of individual gas bubbles (dispersed phase) in a continuous casting mold were simulated using an Eulerian-Lagrangian approach. In order to investigate the effect of bubble size distribution, the radii of bubbles are set with an initial value of 0. 1 — 2. 5 mm which follows the normal distribution. The presented results indicate that, in the submerged entry nozzle (SEN), the distribution of void fraction is only near the wall. Due to the fact that the bubbles motion is only limited to the wall, the deoxidization products have no access to contacting the wall, which prevents clogging. In the mold, the bubbles with a radius of 0. 25 – 2. 5 mm will move to the top surface. Larger bubbles issuing out of the ports will attack the meniscus and induce the fluid flows upwards in the top surface near the nozzle. It may induce mold powder entrapment into the mold. The bubbles with a radius of 0. 1 – 0. 25 mm will move to the zone near the narrow surface and the wide surface. These small bubbles will probably be trapped by the solidification front. Most of the bubbles moving to the narrow surface will flow with the ascending flow, while others will flow with the descending flow.


      PubDate: 2014-04-29T13:50:10Z
       
  • Characteristics of Calcined Magnesite and Its Application in Oxidized
           Pellet Production
    • Abstract: Publication date: April 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 4
      Author(s): Qiang-jian GAO , Guo WEI , Xin JIANG , Hai-yan ZHENG , Feng-man SHEN
      Calcined magnesite is a binding additive and an MgO-bearing flux for pellets production. The effects of calcination temperature and time on the characteristics of calcined magnesite were investigated. Experimental results indicated that the best calcination condition was 850 °C and 1 h. Under this condition, the hydration activity of the calcined magnesite was 80. 56%, and the average diameter of crystal grain D, specific surface area S and the medium particle size D 50 were 25. 4 nm, 45. 40 m2/g and 3. 41 μm, respectively. This kind of calcined magnesite was a good binding additive for pellets production. At the same proportion of calcined magnesite, the effects of activities of calcined magnesite on metallurgical properties of green pellet and indurated pellet showed that calcined magnesite with high activity could improve the dropping strength and compressive strength of green pellet and enhance the burst temperature of green pellet; however, the effects of activity on compressive strength, low-temperature reduction degradation index, reduction swelling index and reduction index of indurated pellet were not obvious.


      PubDate: 2014-04-29T13:50:10Z
       
 
 
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