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  Subjects -> ENVIRONMENTAL STUDIES (Total: 766 journals)
    - ENVIRONMENTAL STUDIES (703 journals)
    - POLLUTION (21 journals)
    - TOXICOLOGY AND ENVIRONMENTAL SAFETY (34 journals)
    - WASTE MANAGEMENT (8 journals)

ENVIRONMENTAL STUDIES (703 journals)            First | 1 2 3 4 5 6 7 8     

International Innovation - climate     Open Access  
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: 14)
International Journal of Environment and Waste Management     Hybrid Journal   (Followers: 5)
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: 6)
International Journal of Health Planning and Management     Hybrid Journal   (Followers: 6)
International Journal of Hygiene and Environmental Health     Hybrid Journal   (Followers: 6)
International Journal of Logistics Research and Applications : A Leading Journal of Supply Chain Management     Hybrid Journal   (Followers: 9)
International Journal of Philosophical Studies     Hybrid Journal   (Followers: 2)
International Journal of Phytoremediation     Hybrid Journal   (Followers: 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  
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: 151)
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: 21)
Journal of Biochemical and Molecular Toxicology     Hybrid Journal   (Followers: 5)
Journal of Black Studies     Hybrid Journal   (Followers: 2)
Journal of Chemical Ecology     Hybrid Journal   (Followers: 1)
Journal of Chemical Health and Safety     Hybrid Journal   (Followers: 2)
Journal of Climate     Full-text available via subscription   (Followers: 22)
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    
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     ISSN (Print) 1006-706X
     Published by Elsevier Homepage  [2563 journals]   [SJR: 0.586]   [H-I: 13]
  • Compressive Behavior of Porous Titanium Fiber Materials
    • Abstract: Publication date: August 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 8
      Author(s): Shi-feng LIU , Zheng-ping XI , Hui-ping TANG , Xin YANG , Zhao-hui ZHANG
      Porous titanium fiber materials with the fiber sizes of 70—120 μm in diameter were prepared by vacuum sintering technology. The morphology and compressive properties of porous titanium fiber materials were investigated by using a scanning electron microscope (SEM) and an MST 858 compression testing machine in quasi-static condition. The results show that porous titanium fibers form complex micro-networks. The stress-strain curves of porous titanium fiber materials exhibit clastic region, platform region and densification region and no collapse during platform region. The yield strength of porous titanium fiber materials decreases with increasing the porosity and increasing the fiber diameter.


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


      PubDate: 2014-08-16T06:32:32Z
       
  • Combined Effects of Different Overload Ratios and Nitriding Process on
           Fatigue Crack Growth of AISI 4140 Steel
    • Abstract: Publication date: August 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 8
      Author(s): A.B. Sengül , A. Çelik
      The combined effects of different overload ratios (OLRs) and nitriding process on fatigue crack growth (FCG) were analyzed. Steel compact tension specimens made of AISI 4140 steel were subjected to the plasma nitrification process using a gas mixture of 50% N2 and 50% H2 at 500 °C for 2 h. Structural properties of the samples were studied by scanning electron microscopy, optical microscopy, microhardness testing and digital imaging. Plasma nitriding slowed down FCG, but the crack growth retardation caused by the overload was reduced when the OLR was 2. 0 and 2. 5. Nitriding did not take effect when the OLR was 1.5 and 3.0.


      PubDate: 2014-08-16T06:32:32Z
       
  • Inhibition Effects of Chloroquinolines on Corrosion of Mild Steel in
           Hydrochloric Acid Solution
    • Abstract: Publication date: August 2014
      Source:Journal of Iron and Steel Research, International, Volume 21, Issue 8
      Author(s): A.V. Shanbhag , T.V. Venkatesha , B.M. Praveen , S. B. Abd Hamid
      The corrosion inhibition efficiencies of four compounds namely N-[(1E)-(2-chloroquinolin-3-yl) methylene]-N-phenylamine(CQMA), N-(1E)-(2-chloroquinolin-3-yl) methylene]-N-(4-fluorophenyl) amine (CQMFA), N-(4-chloro phenyl)-N-[(1E)-(2-chloroquinolin-3-yl) methylene]amine (CQMCA), and N-(4-bromo phenyl)-N-[(1E)-(2-ehloroquinolin-3-yl) methylene]amine (CQMBA) on mild steel corrosion in hydrochloric acid media were investigated using mass loss, potentiodynamic polarization and electrochemical impedance spectroscopy. For all the studied inhibitors the inhibition efficiency values were found to increase with increasing concentration up to 5.00 × 10−4 mol · dm−3. Scanning electron microscopic technique showed the formation of a thick film on the steel surface in the presence of inhibitors.


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


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


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


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


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


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


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


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


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


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