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  Subjects -> ENVIRONMENTAL STUDIES (Total: 799 journals)
    - ENVIRONMENTAL STUDIES (729 journals)
    - POLLUTION (22 journals)
    - TOXICOLOGY AND ENVIRONMENTAL SAFETY (39 journals)
    - WASTE MANAGEMENT (9 journals)

ENVIRONMENTAL STUDIES (729 journals)            First | 1 2 3 4 5 6 7 8     

Indiana Journal of Global Legal Studies     Full-text available via subscription   (Followers: 2)
Indoor Air     Hybrid Journal   (Followers: 1)
Information Systems Management     Hybrid Journal   (Followers: 22)
Information Technology and Management     Hybrid Journal   (Followers: 9)
IngenierĂ­a HidrĂ¡ulica y Ambiental     Open Access  
Inhalation Toxicology     Hybrid Journal   (Followers: 7)
Integrated Environmental Assessment and Management     Hybrid Journal   (Followers: 5)
Interdisciplinary Environmental Review     Hybrid Journal   (Followers: 4)
Interfaces     Full-text available via subscription   (Followers: 6)
International Aquatic Research     Open Access   (Followers: 3)
International Archives of Occupational and Environmental Health     Hybrid Journal   (Followers: 4)
International Environmental Agreements: Politics, Law and Economics     Hybrid Journal   (Followers: 11)
International Gambling Studies     Hybrid Journal   (Followers: 6)
International Innovation - climate     Open Access   (Followers: 1)
International innovation. Environment     Open Access  
International Journal of Acarology     Hybrid Journal   (Followers: 1)
International Journal of Advancement in Earth and Enviromental Sciences     Open Access   (Followers: 2)
International Journal of African Renaissance Studies - Multi-, Inter- and Transdisciplinarity     Hybrid Journal   (Followers: 2)
International Journal of Agricultural and Environmental Information Systems     Full-text available via subscription   (Followers: 2)
International Journal of Alternative Propulsion     Hybrid Journal   (Followers: 1)
International Journal of Applied Psychoanalytic Studies     Hybrid Journal   (Followers: 2)
International Journal of Chinese Culture and Management     Hybrid Journal   (Followers: 1)
International Journal of Corrosion     Open Access   (Followers: 10)
International Journal of Critical Infrastructures     Hybrid Journal   (Followers: 3)
International Journal of Disaster Risk Reduction     Hybrid Journal   (Followers: 6)
International Journal of Disaster Risk Science     Open Access   (Followers: 9)
International Journal of Ecological Economics and Statistics     Full-text available via subscription   (Followers: 1)
International Journal of Ecology     Open Access   (Followers: 8)
International Journal of Ecology & Development     Full-text available via subscription   (Followers: 2)
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: 5)
International Journal of Environment and Sustainable Development     Hybrid Journal   (Followers: 16)
International Journal of Environment and Waste Management     Hybrid Journal   (Followers: 6)
International Journal of Environment, Workplace and Employment     Hybrid Journal   (Followers: 3)
International Journal of Environmental Engineering     Hybrid Journal   (Followers: 5)
International Journal of Environmental Health Engineering     Open Access  
International Journal of Environmental Health Research     Hybrid Journal   (Followers: 2)
International Journal of Environmental Policy and Decision Making     Hybrid Journal   (Followers: 10)
International Journal of Environmental Protection     Open Access   (Followers: 12)
International Journal of Environmental Research and Public Health     Open Access   (Followers: 16)
International Journal of Environmental Science and Technology     Hybrid Journal   (Followers: 6)
International Journal of Environmental Studies     Hybrid Journal   (Followers: 10)
International Journal of Exergy     Hybrid Journal   (Followers: 4)
International Journal of Forest, Soil and Erosion     Open Access   (Followers: 3)
International Journal of Global Environmental Issues     Hybrid Journal   (Followers: 4)
International Journal of Global Warming     Hybrid Journal   (Followers: 5)
International Journal of Greenhouse Gas Control     Partially Free   (Followers: 6)
International Journal of Health Planning and Management     Hybrid Journal   (Followers: 6)
International Journal of Hygiene and Environmental Health     Hybrid Journal   (Followers: 6)
International Journal of Logistics Research and Applications : A Leading Journal of Supply Chain Management     Hybrid Journal   (Followers: 10)
International Journal of Philosophical Studies     Hybrid Journal   (Followers: 2)
International Journal of Phytoremediation     Hybrid Journal   (Followers: 2)
International Journal of Process Systems Engineering     Hybrid Journal   (Followers: 1)
International Journal of Recycling of Organic Waste in Agriculture     Open Access   (Followers: 1)
International Journal of Regulation and Governance     Hybrid Journal   (Followers: 2)
International Journal of Reliability and Safety     Hybrid Journal   (Followers: 7)
International Journal of Renewable Energy Development     Open Access   (Followers: 6)
International Journal of Social Sciences and Management     Open Access  
International Journal of Soil, Sediment and Water     Open Access   (Followers: 8)
International Journal of Stress Management     Full-text available via subscription   (Followers: 9)
International Journal of Sustainable Construction Engineering and Technology     Open Access   (Followers: 8)
International Journal of Sustainable Engineering     Hybrid Journal   (Followers: 7)
International Journal of Sustainable Materials and Structural Systems     Hybrid Journal   (Followers: 5)
International Journal of Sustainable Society     Hybrid Journal   (Followers: 7)
International Journal of Testing     Hybrid Journal   (Followers: 1)
International Journal of the Commons     Open Access   (Followers: 3)
International Journal of Toxicology     Hybrid Journal   (Followers: 7)
International Journal of Water Resources and Environmental Engineering     Open Access   (Followers: 1)
International Review of Environmental and Resource Economics     Full-text available via subscription   (Followers: 1)
International Studies in the Philosophy of Science     Hybrid Journal   (Followers: 10)
Interventions : International Journal of Postcolonial Studies     Hybrid Journal   (Followers: 10)
IOP Conference Series: Earth and Environmental Science     Open Access   (Followers: 7)
Iranian Studies     Hybrid Journal   (Followers: 10)
Irish Educational Studies     Hybrid Journal   (Followers: 2)
Irish Journal of Earth Sciences     Full-text available via subscription  
Irish Political Studies     Hybrid Journal   (Followers: 10)
ISLE: Interdisciplinary Studies in Literature and Environment     Hybrid Journal   (Followers: 1)
Isotopes in Environmental and Health Studies     Hybrid Journal   (Followers: 1)
Israel Studies     Full-text available via subscription   (Followers: 5)
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 Advanced Research in Civil and Environmental Engineering     Open Access   (Followers: 1)
Journal of Advances in Environmental Health Research     Open Access   (Followers: 1)
Journal of Agricultural and Environmental Ethics     Hybrid Journal   (Followers: 9)
Journal of Agricultural Biotechnology and Sustainable Development     Open Access  
Journal of Agricultural Chemistry and Environment     Open Access  
Journal of Agriculture and Environment     Open Access   (Followers: 1)
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: 258)
Journal of Applied Meteorology and Climatology     Full-text available via subscription   (Followers: 8)
Journal of Applied Psychoanalytic Studies     Hybrid Journal   (Followers: 1)
Journal of Applied Sciences and Environmental Management     Open Access   (Followers: 1)
Journal of Applied Sciences in Environmental Sanitation     Open Access   (Followers: 6)
Journal of Applied Toxicology     Hybrid Journal   (Followers: 10)

  First | 1 2 3 4 5 6 7 8     

Journal Cover   Journal of Iron and Steel Research, International
  [SJR: 0.784]   [H-I: 16]   [9 followers]  Follow
    
   Full-text available via subscription Subscription journal
   ISSN (Print) 1006-706X
   Published by Elsevier Homepage  [2654 journals]
  • Model of Iron Ore Sintering Based on Melt and Mineral Formation
    • Abstract: Publication date: April 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 4
      Author(s): Jun ZHANG , Xing-min GUO , Yuan-hong QI , Ding-liu YAN
      A model of iron ore sintering was built with consideration of fuel combustion, catalysis of sinter mixture as well as formation of melt and mineral, which was verified via sintering pot tests and showed a good fit to the experimental results. The effect of bed depth on temperature was reflected by the residence time in high-temperature zone, rather than the top value of the temperature, which was weakened by melt formation as well as hematite decomposition. Moreover, the effect of bed depth, fuel content and distribution on sintering process was different, which was reflected by temperature profiles and the rule of calcium ferrite formation. The formation of melt as well as magnetite was a process which was decided by kinetic factors, while the formation of calcium ferrite was related to fuel blending conditions, which is determined by thermodynamics when the fuel ratio inside sinter granules is low or fuel content is high, otherwise, it is determined by kinetics.


      PubDate: 2015-04-13T01:01:09Z
       
  • Velocity Preset and Transitional Zone's Shape Optimization for Tailor
           Rolled Blank
    • Abstract: Publication date: April 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 4
      Author(s): Dong-cheng WANG , Lian-chao DONG , Hong-min LIU , Yan WANG
      Tailor rolled blank (TRB) is a type of emerging material to produce lightweight vehicle parts. Transitional zone's shape is an important parameter for tailor rolled blank. It not only affects mold design and the local carrying capacity of the stamping parts, but also determines the maximum value and variation characteristics of rolling force. How to get the best transitional zone's shape is a key problem for production of tailor rolled blank. A double power function is put forward using for transitional curve, which is continuous and smooth at all connection points independent of its parameters, so the sudden change of mechanical parameters during rolling and forming process can be avoided. At the same time, the velocity formula and restriction for arbitrary transitional curve are derived to preset vertical velocity of the roller and judge whether the curve can be rolled successfully or not. Then, the finite element method (FEM) is used to verify the precision of velocity formula and study the mechanical characteristics of different curves. Finally, a method to obtain the optimal curve equation is put forward and verified.


      PubDate: 2015-04-13T01:01:09Z
       
  • A Novel Low-cost Hot Rolled High Strength Steel for an Automatic Teller
           Machine
    • Abstract: Publication date: March 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 3
      Author(s): Bin ZENG , Zhao-dong LI , Xin-jun SUN , Qi-long YONG , Yu-qing WENG
      A novel hot rolled steel LG600A with the tensile strength exceeding 700 MPa was developed for automatic teller machine application. The low-cost C-Mn steel was microalloyed with 0.08 mass% – 0.12 mass% Ti rather than noble alloying elements, such as Nb, V, Mo, and Cu, etc. The novel steel had a good surface quality and welding property. After the hot rolled steel coils were leveled, the steel plates, the length of which was even down to 1500 mm, had an excellent flatness. The effects of hot rolling parameters on mechanical performance, microstructure and recrystallization behavior were studied. The metallurgical concept for the steel production was also discussed. The result shows that decreasing the finish rolling temperature, increasing cooling rate in the first cooling stage and decreasing the cooling rate in the last cooling stage, together with coiling at a modestly high coiling temperature all resulted in the refined grains and TiC precipitates, thereby improving the strength and toughness of this new steel greatly.


      PubDate: 2015-04-13T01:01:09Z
       
  • Macro and Micro Behaviors of Low Alloyed TRIP780 Steel with Different
           Biaxial Proportional Loading
    • Abstract: Publication date: March 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 3
      Author(s): Hong-yang LI , Yan-jing ZHANG , Wen-jun ZHAO , Zhi-fei GU , Xian-chao LI , Jin-long MA
      To investigate the macro and micro behaviors of TRIP (transformation induced plasticity) steel under biaxial loading, experiment and finite element simulation were carried out for TRIP780 steel under proportional biaxial tension with displacement ratio of 1 : 1, 2 : 1, 3 : 1 and 4 : 1, respectively. The results show that cruciform specimens of TRIP780 steel fractured under proportional biaxial stretching when effective strain was about 1.5%, and fracture was always generated on the cross arm or cross links. During biaxial tension, stress and strain components in x and y directions of the center of the samples have the same nonlinear developing tendency, decreasing in one direction and increasing in another direction. Equal biaxial stretching stress state was helpful for retained austenite-martensite transformation than the other biaxial stress state. With increasing displacement ratio (DR) from 1 : 1 to 4 : 1, corresponding stress distributed unevenly on the yield ellipse from 30° to 60° in the first quadrant of stress space and corresponding retained austenite volume fraction distributed symmetrically in bow tie format.


      PubDate: 2015-04-13T01:01:09Z
       
  • Dynamic Recrystallization Behavior of Medium Carbon Cr-Ni-Mo-Nb Steel
           during Hot Deformation
    • Abstract: Publication date: March 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 3
      Author(s): Shi-li ZHU , Hua-zhen CAO , Jian-song YE , Wen-hao HU , Guo-qu ZHENG
      Hot compression deformation behaviors of medium carbon Cr-Ni-Mo-Nb steel were investigated at deformation temperatures ranging from 1223 to 1423 K and strain rates of 0.1, 1 and 5 s−1. Dynamic recovery (DRV) and dynamic recrystallization (DRX) were observed during the hot compression deformation. For all of the samples, DRX occurred at deformation temperatures above 1323 K at different strain rates, while below 1223 K, no DRX was observed. The activation energy of the tested steel was determined as 386.06 kJ/mol. The ratio of critical stress to peak stress and the ratio of critical strain to peak strain were 0.835 and 0.37, respectively. Kinetic equations interpreting the DRX behavior of the tested steel were proposed, and the corresponding parameters including the volume fraction and the average grain size were determined. Moreover, the microstructures induced under different deformation conditions were analyzed.


      PubDate: 2015-04-13T01:01:09Z
       
  • Carbides Evolution in 12Cr Martensitic Heat-resistant Steel with Life
           Depletion for Long-term Service
    • Abstract: Publication date: March 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 3
      Author(s): Zheng-fei HU , Da-hai HE , Fan MO
      Evaluating the residual life of exposed components in power industry is a very important procedure in routine examination. The microstructures of a series of X20CrMoV12. 1 martensitic superheater tube samples in a boiler in different service periods were investigated extensively to extract a quantitative relationship. During long-term service from start to rupture, hardness decreased monotonically with life depletion, and the decrease of hardness in prior austenite grain boundary was steeper than that in the matrix. Microstructure observation showed obvious damage characteristics, including carbide coarsening and martensite decomposing, and the martensite structure decomposed completely in rupture state. The morphology, distribution and composition of the main precipitates M23C6 varied distinctly. The aspect ratio of coarsened carbides along grain boundary increased several fold with respect to their original size. The composition of coarsened M23C6 carbide shows the most regular trend of Cr enrichment and the statistical result of Cr enrichment in M23C6 shows a linear correlation between the ratio of Cr to Fe and service time to the power of 3/2, which may be considered as an index of material degradation due to long-term service exposure.


      PubDate: 2015-04-13T01:01:09Z
       
  • Effect of Mischmetal on As-cast Microstructure and Mechanical Properties
           of M2 High Speed Steel
    • Abstract: Publication date: March 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 3
      Author(s): Qiu-xiang LIU , De-ping LU , Lei LU , Qiang HU , Qing-feng FU , Zhe ZHOU
      High speed steel has been widely used in various fields due to their excellent red hardness and good wear resistance. However, the influence of mischmetal (Ce-La) on the as-cast microstructures and mechanical properties of high speed steel has rarely been reported. Thus, the microstructure and mechanical properties of M2 high speed steel with addition of mischmetal (Ce-La) were investigated. The morphology and distribution of the eutectic carbides of the steel were observed by using optical microscopy and scanning electron microscopy, and the impact toughness and bending strength were tested. The results show that adding mischmetal has an obvious effect on the microstructure and mechanical properties of M2 high speed steel. The coarse eutectic structure is refined, the weak connection of the carbide networks is broken and the flake carbides become short and fine. More networks of eutectic carbides dissolve into the matrix. When a suitable adding content of mischmetal is selected, for example, 0.3 mass%, the impact strength and bending strength can increase by 27% and 10.76% compared with that without mischmetal, respectively.


      PubDate: 2015-04-13T01:01:09Z
       
  • Effect of Si Content and Temperature on Oxidation Resistance of Fe-Si
           Alloys
    • Abstract: Publication date: March 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 3
      Author(s): Xiao-jiang LIU , Yong-quan HE , Guang-ming CAO , Tao JIA , Teng-zhi WU , Zhen-yu LIU
      Hot-rolled Fe-(0. 75–2. 20) Si (mass%) alloys were oxidized in dry air at 600–1200 °C. The oxidation process was carried out by thermal gravimetric analysis (TGA). At 600–1150 °C, oxidation gain curves were approximately parabolic. Electron probe microanalysis (EPMA) was applied to investigate cross-section morphology of oxide layer and element distribution across the layer. At lower temperature of 700 °C, the oxide layer consisted of internal oxidation zone (IOZ), inner Si-rich layer (conglomerate of fayalite and magnetite) and outer hematite layer, while at higher temperature of 1200 °C, fayalite and wustite were observed in external oxide scale. Liquidus temperature of fayalite was detected by differential scanning calorimetry (DSC). Through comparing the oxidation mass gain and parabolic rate constant of the alloys, it was found that oxidation resistance of Fe-Si alloy was enhanced by increasing Si content below 1150 °C while increasing Si content of the alloy resulted in higher oxidation rate above 1150 °C owing to the liquid fayalite formation.


      PubDate: 2015-04-13T01:01:09Z
       
  • Multi-boiler System Optimization in Integrated Steelworks Based on
           Decomposition and Coordination Method
    • Abstract: Publication date: March 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 3
      Author(s): Guang-yu MA , Wen-qiang SUN , Wei-dong LI , Zhu YE , Jiu-ju CAI
      As for the existing problems of boilers in integrated steelworks, the multi-boiler system could be quantitatively optimized with the decomposition and coordination method. Then, case studies were carried out based on the data of an integrated steelworks. Two groups of actual production records were contrastively analyzed, and the calculation results from the optimized program of these two groups indicated that for groups 1 and 2, the costs fall by 5. 06% and 3. 79% and the fuel consumptions decrease by 2. 72% and 1.45%, respectively, compared with the actual data. To analyze the cost and fuel consumption change under the same condition of total load demand, assigned fuel consumption and water temperature, five sets of data were selected for further analysis. It was shown that the total cost and fuel consumption of the optimized program could fall by 3. 5% and 1. 6% respectively, compared with the actual production records. The optimal allocation significantly contributed to energy conservation and cost reduction. The effects of the system energy conservation cannot be realized by single equipment energy conservation. They were complementary to each other, and should be put on the same stage.


      PubDate: 2015-04-13T01:01:09Z
       
  • Combination Effect of Si and P on Tertiary Scale Characteristic of Hot
           Rolled Strip
    • Abstract: Publication date: March 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 3
      Author(s): Yang YU , Chang WANG , Lin WANG , Jin CHEN , Ya-jun HUI , Chang-ku SUN
      For high strength interstitial free (IF) steel containing P element, the salt and pepper (SP) defects exist on the strip surface and could not be eliminated effectively by optimizing the hot rolling process, such as temperature and cooling water. The combination effect of Si and P on the characteristic of tertiary scale has been studied comprehensively by scanning electron microscopy (SEM) and electron probe microanalysis (EPMA), and the concept is proposed firstly that Si and P are of combination effect which can be utilized to eliminate the SP defect. The results show that the SP defects were induced by the rolled-in scale during finish rolling. P can be enriched at the interface between substrate and tertiary scale, which is easy to decrease the adhesion of tertiary scale. However, Si enrichment at the interface between substrate and tertiary scale can increase the adhesion. The SP defects can be eliminated completely, which is attributed to the accompanying enrichment of Si and P.


      PubDate: 2015-04-13T01:01:09Z
       
  • Strength Activity Index of Air Quenched Basic Oxygen Furnace Steel Slag
    • Abstract: Publication date: March 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 3
      Author(s): Lei GAN , Hai-feng WANG , Xiu-ping LI , Yuan-hong QI , Chun-xia ZHANG
      Air quenched basic oxygen furnace steel slag (BOF-SS) is processed at very high cooling rate, which is expected to have different cementitious properties from conventional slowly cooled BOF-SS. For this purpose, the strength activity indexes of air quenched and slowly cooled BOF-SS are investigated. The results reveal that, under the specific surface area (S) of 490 m2/kg, the compressive strength activity index reaches 1. 24 after 28 days with replacement of 15% air quenched BOF-SS and reaches 1.05 after 28 days with replacement of 20% air quenched BOF-SS and 30% granulated blast furnace slag (GBFS). The cementitious activity of air quenched BOF-SS is obviously higher than that of slowly cooled BOF-SS, mainly because it contains more C3S and glassy phases.


      PubDate: 2015-04-13T01:01:09Z
       
  • Effect of Solute Elements and Cooling Rate on Strain in Brittle
           Temperature Range of Continuously Cast Strand
    • Abstract: Publication date: March 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 3
      Author(s): Hui ZHANG , Yi FAN , Ming-lin WANG , Hong-biao TAO
      A micro-segregation model of solute elements in mushy zone with δ/γ transformation during solidification was established based on the regular hexagon transverse cross section of dendrite shape proposed by finite difference method under the non-equilibrium solidification condition. The model was used to calculate the non-equilibrium pseudo binary Fe-C phase diagram and the strain of steels induced by variation of temperature in brittle temperature range. On the basis of the phase diagram and the strain, the strain curve in brittle temperature range as a function of carbon content for continuously cast strand was introduced and obtained. Solute elements change the position of the strain curve. And cooling rate changes the position and the shape of the strain curve. The comprehensive formula of the strain as functions of solute elements and cooling rate in brittle temperature range has been obtained by nonlinear fitting program.


      PubDate: 2015-04-13T01:01:09Z
       
  • Thermodynamic Analysis of Formation of Fluoride from Gangue in Bayan Obo
           Iron Concentrate Containing Fluorite
    • Abstract: Publication date: March 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 3
      Author(s): Fang ZHANG , Sheng-li AN , Yi-ci WANG , Guo-ping LUO , Xiao-long SONG
      In order to fill up the deficiency of the theoretical basis about fluoride formation during Bayan Obo iron concentrate roasting process, the thermodynamic conditions of the interactivity between the components of the gangue and calcium fluorite were studied by means of thermodynamic calculation, DTA-TG thermal analysis and XRD characterization. The results revealed that KF, NaF and SiF4 (gaseous) could be formed during the roasting process, and the tendency of the generation of KF is greater than that of NaF or SiF4 in standard state. Besides, the results of roasting experiments showed that the products of KCaCO3 F and KCaF3 formed in the temperature range of 800–1250 °C and KF appears when the roasting temperature was higher than 1250 °C in K2 O-CaF2 system. For the Na2 O-CaF2 system, the product of NaF appears at temperature higher than 1050 °C. The formation reaction of gaseous SiF4 with solid phase CaO – SiO2 in SiO2-CaF2 system took place only at temperature higher than 1150 °C. In the natural potash feldspar-CaF2-CaO system, the fluorination reaction products involved KF at temperature higher than 1270 °C, while in the natural aegirine-CaF2-CaO system, NaF formed at temperature higher than 980 °C during roasting process.


      PubDate: 2015-04-13T01:01:09Z
       
  • Establishment of a Static Model Based on Measured Heat Loss for COREX
           Process
    • Abstract: Publication date: March 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 3
      Author(s): Wei SHEN , Sheng-li WU , Ming-yin KOU , Kai-ping DU , Ying SUN
      The heat loss and its distribution are of great importance for the calculation and simulation of COREX process. Based on Baosteel COREX process, a method was applied to measure the heat loss of the furnace shell, the accessory equipments and the cooling water system. Then, a static model was established based on the measured heat loss of COREX process. The results showed that the main heat loss of furnace shells took place at the dome of the COREX melter-gasifier and the reducing gas entrance position of the shaft furnace while the main heat loss caused by cooling water occurred at the tap hole area. And the heat loss caused by cooling water accounts for about 85% of the total heat loss in COREX process. The measured total heat loss for producing every 1 t hot metal was 542. 164 MJ, which accounted for about 92% of the theoretical total heat loss.


      PubDate: 2015-04-13T01:01:09Z
       
  • Mathematical Modeling of ESR Process for Hollow Ingot with Current
           Supplying Mould
    • Abstract: Publication date: March 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 3
      Author(s): Xu CHEN , Fu-bin LIU , Zhou-hua JIANG , Hua-bing LI , Xi-min ZANG , Xin DENG
      With increasing demand for large cylindrical forgings, a new technology–electroslag remelting (ESR) for direct manufacture of hollow ingots rather than solid ingots has been developed. The main features of the process include a T-shaped current supplying mould (CSM), double power supply, an ingot withdrawing system, a metal level automatic control system based on a level sensor using the electromagnetic eddy current method, and the exchange of a consumable multi-electrode. ANSYS software was used to calculate the fluid flow and heat transfer in the slag bath and metal pool of this ESR hollow ingot process with its T-shaped CSM. The mathematical model was verified by measuring the geometry of the liquid metal pool as observed in the macrostructure of ϕ650 mm (external diameter)/ϕ450 mm (internal diameter) hollow ingots by sulphur print method: the observed shape and depth of the slag bath were consistent with the simulated results. Simulation of the ESR process can improve understanding of the process and allow better operating parameters to be selected.


      PubDate: 2015-04-13T01:01:09Z
       
  • Rectangular Section Control Technology for Silicon Steel Rolling
    • Abstract: Publication date: March 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 3
      Author(s): Xiao-chen WANG , Quan YANG , You-zhao SUN
      Rectangular section control technology (RSCT) was introduced to achieve high-precision profile control during silicon steel rolling. The RSCT principle and method were designed, and the whole RSCT control strategy was developed. Specifically, RSCT included roll contour design, rolling technology optimization, and control strategy development, aiming at both hot strip mills (HSMs) and cold strip mills (CSMs). Firstly, through the high-performance variable crown (HVC) work roll optimization design in the upper-stream stands and the limited shifting technology for schedule-free rolling in the downstream stands of HSMs, a hot strip with a stable crown and limited wedge, local spot, and single wave was obtained, which was suitable for cold rolling. Secondly, an approximately rectangular section was obtained by edge varying contact (EVC) work roll contour design, edge-drop setting control, and closed loop control in the upper-stream stands of CSMs. Moreover, complex-mode flatness control was realized by coordinating multiple shape-control methods in the downstream stands of CSMs. In addition, the RSCT approach was applied in several silicon-steel production plants, where an outstanding performance and remarkable economic benefits were observed.


      PubDate: 2015-04-13T01:01:09Z
       
  • Effects of Pre-strain and Temperature on Bake Hardening of TWIP900CR Steel
    • Abstract: Publication date: April 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 4
      Author(s): Suleyman KILIC , Fahrettin OZTURK , Tayfun SIGIRTMAC , Gokhan TEKIN
      The effects of pre-strain and baking temperature on bake hardening behaviour of TWIP900CR steel were investigated. The results reveal that the bake hardening process contributes to an increase in yield strength up to 65 MPa at the baking temperature of 200 °C. The difference in yield strength between baking temperatures of 170 and 200 °C is almost insignificant. It is clearly observed that baking at a high temperature does not result in a significant increase in yield strength. For a reasonable bake hardening, a good combination of pre-strain and baking temperature is necessary. Besides, the toughness of the material is found to decrease with increasing pre-strain.


      PubDate: 2015-04-13T01:01:09Z
       
  • Cementite Characterization with Chromium and Vanadium Contents Using
           Indentation Technique
    • Abstract: Publication date: April 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 4
      Author(s): John Jairo CORONADO , Sara Aida RODRÍGUEZ
      Cast irons with some kinds of cementite with different chromium and vanadium contents were characterized. Fracture toughness was determined by using an indentation technique, along with microhardness and elastic modulus. The results show that at the load of 1 N, microhardness of the cementite with 5. 1% Cr is 10. 53 GPa, the microhardness for cementite with 9. 2% Cr increased to 11. 25 GPa and for cementite with 4. 5% V the microhardness is 9. 18 GPa. The cementite with 9. 2% Cr presented the highest elastic modulus of 230. 4 GPa and the cementite with 4% V presented the lowest value of 201. 32 GPa. Cementite with 5. 1% Cr presented higher fracture toughness than cementite with 9. 2% Cr; however, cementite with 4. 5% V presented the highest fracture toughness of 2. 74 MPa · m½ and the lowest brittleness index of 3. 35 μm−½.


      PubDate: 2015-04-13T01:01:09Z
       
  • Simulated Corrosion Test of Q235 Steel in Diatomite Soil
    • Abstract: Publication date: April 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 4
      Author(s): Jian LI , Hang SU , Feng CHAI , Xiao-ping CHEN , Xiang-yang LI , Hui-min MENG
      Through the study of the corrosion behavior of Q235 steel in actual Yingtan soil and two simulated acidic soils with different water contents, the calculation of corrosion mass losses, and the analysis of the corrosion morphologies and products by means of scanning electron microscope (SEM) and X-ray diffraction (XRD), the results demonstrated that the diatomite soil could simulate the corrosion in actual soil veritably. In both actual soil and simulated soil with 16. 4% water content, the corrosion rates of Q235 steel were approximately 0. 1 mm/a, the corrosion morphologies were mainly extension and connection of corrosion spots on sample surface, and the corrosion products were composed of α-FeOOH, γ-FeOOH, Fe3O4 and Fe2O3. When other media conditions remained unchanged, the corrosion area of Q235 steel was larger in simulated soil with 34. 5% water content, and the corrosion rate reached 0. 48 mm/a after 360 h of corrosion, which was nearly 5 times as the value in actual soil. Compared with the corrosion products in actual soil, the proportion of γ-FeOOH in simulated soil with 34. 5% water content was higher, and the w α-FeOOH/w γ-FeOOH ratio was 1. 4, which was only 1/3 of the value in actual soil.


      PubDate: 2015-04-13T01:01:09Z
       
  • Microstructural Evolution and Properties of a High Strength Steel with
           Different Direct Quenching Processes
    • Abstract: Publication date: April 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 4
      Author(s): Feng LU , Chao WANG , Long LÜ , Zhao-dong WANG , Guo-dong WANG , Raja Devesh Kumar MISRA
      A high strength low alloy steel with low carbon equivalent was selected for simulating online direct quenching and coiling (DQ-C) process. The influence of stop quenching temperature on mechanical properties and microstructures was studied and compared with normal direct quenching and tempering (DQ-T) process. The study confirmed that required mechanical properties were obtained for both the processes. Properties of the experimental steel with DQ-C process could reach the same level as that of DQ-T process in general. In the DQ-C process, strength decreased with increase in stop quenching temperature. Martensite was obtained and experienced an aging process at stop quenching temperature below M f. On fast cooling below M s, martensite was partially transformed and carbon partitioning occurred during slow cooling. The reduction in solid solution carbon and increased amount of retained austenite led to lower strength compared with the DQ-T process. DQ-C process was more favorable for microalloy carbide precipitation. However, impact toughness under different cooling conditions was adequate because of low carbon equivalent and refined microstructure.


      PubDate: 2015-04-13T01:01:09Z
       
  • Microstructure and Mechanical Properties of Precipitation Strengthened
           Fire Resistant Steel Containing High Nb and Low Mo
    • Abstract: Publication date: April 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 4
      Author(s): Zheng-yan ZHANG , Qi-long YONG , Xin-jun SUN , Zhao-dong LI , Jun-yu KANG , Guo-dong WANG
      Through the thermo-mechanical control process (TMCP), a high Nb low Mo fire resistant steel with the yield strength (YS) of 521 MPa at room temperature (RT) and 360 MPa at elevated temperature (ET) of 600 °C was developed based on MX (M=Nb, V, Mo; X=C, N) precipitation strengthening. A series of tensile and constant load tests were conducted to study the mechanical properties at ET. The dynamic continuous cooling transformation (CCT) as well as precipitation behavior of microalloy carbonitride was investigated by means of thermal simulator and electron microscopy approaches. Results showed that the failure temperature of tested steel was determined as 653 °C, and the granular bainite was obtained when the cooling rate was higher than 10 °C/s. In the rolled state, a certain amount of M/A islands was observed. During heating from RT to ET, M/A islands disappeared, and cementites and high dense compound precipitates (Nb, Mo, V)C with size of less than 10 nm precipitated in ferrite at ET (600 °C), which resulted in precipitation strengthening at ET.


      PubDate: 2015-04-13T01:01:09Z
       
  • Carbide Evolution in High Molybdenum Nb-microalloyed H13 Steel during
           Annealing Process
    • Abstract: Publication date: April 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 4
      Author(s): Tian-sheng LI , Fu-ming WANG , Chang-rong LI , Guo-qing ZHANG , Qing-yong MENG
      Based on the Thermo-Calc thermodynamic software, the type of equilibrium precipitated carbides and their contents in high Mo Nb-microalloyed H13 steel (NMH13 steel) were calculated. The composition, morphology, and distribution of carbides after spheroidal annealing of two forged experimental steels were comparatively examined by means of optical microscopy (OM), scanning electron microscopy (SEM), electron dispersive spectroscopy (EDS) and transmission electron microscopy (TEM). VC, M23C6 and M6C are identified in H13 steel after spheroidizing annealing, while (V, Nb)C, M23C6, M2C and M6C are observed in NMH13 steel. Moreover, it is found that the addition of Nb significantly enhances the stability of MC phase and the high Mo content accelerates the precipitation of small rod-shape M2C phase in NMH13 steel. The amount of the fine carbides in NMH13 steel obviously increased with M2C and M6C precipitated from the ferrite phase, which is in accordance with the results of thermodynamic calculations.


      PubDate: 2015-04-13T01:01:09Z
       
  • Effects of Different Substrates on Microstructures and Mechanical
           Properties of a Bulk Nanocrystalline Structure Pure Iron Prepared by
           Aluminothermic Reaction Casting
    • Abstract: Publication date: April 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 4
      Author(s): Xiao-juan ZHEN , Pei-qing LA , Cui-ling LI , Su-lei HU
      A simple method was developed to produce the nanocrystalline pure iron by aluminothermic reaction casting. The microstructure of the iron was investigated by optical microscope (OM), transmission electron microscope (TEM), electron probe micro-analyzer (EPMA), scanning electron microscope (SEM) and X-ray diffraction (XRD). The mechanical performances of nanocrystalline pure iron were tested. It is found that the pure iron consists of nanocrystalline ferrite. For different substrates of copper and glass, the average grain size of the ferrite was 38 and 35 nm, respectively, which is larger on copper substrate than that on glass. The hardness, compressive strength, tensile strength, and total elongation are 167 and 137 HB, 400 and 500 MPa, 243 and 185 MPa, 16% and 10% on copper substrate and glass substrate, respectively. The hardness, tensile strength and total elongation are all larger on copper substrate than those on glass substrate, while the compressive strength is lower. The large supercooling in the product solidification provides the condition for high nucleation rate and thus leads to nano-grained austenite and final nano-grained ferrite transformed from those small austenite grains.


      PubDate: 2015-04-13T01:01:09Z
       
  • Solid-phase Decarburization Kinetics of High-carbon Ferromanganese Powders
           by Microwave Heating
    • Abstract: Publication date: April 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 4
      Author(s): Li-na GUO , Jin CHEN , Jing ZHAO , Wan-ming LIN , Wen-li SHI , Min LIANG
      Solid-phase decarburization of high-carbon ferromanganese powders (HCFPs) was conducted using calcium carbonate powders (CCPs) as a decarburizer by microwave heating. Solid-phase decarburization kinetics was investigated by isothermal method. The results show that the HCFPs show excellent microwave absorption at a higher average heating rate of 80 °C/min, while CCPs exhibit poor microwave absorption at a lower heating rate of 5—20 °C/min; the heating characteristics are in-between when HCFPs and CCPs are mixed. The average heating rates of the mixture are 32. 14, 31. 25, 31. 43, and 30. 77 °C/min when the mixture is heated up to 900, 1000, 1100, and 1200 °C, respectively. The good microwave absorption property of the mixed material lays the foundation for the solid-phase decarburization of HCFPs containing CCPs. Solid-phase decarburization of HCFPs containing CCPs is a first-order reaction by microwave heating. Apparent activation energy of solid-phase decarburization is 55. 07 kJ/mol, which is far less than that of ordinary carbon gasification reaction and that of solid-phase decarburization under the same decarburization condition by conventional heating. It indicates that microwave heating not only produces thermal effect, but also has non-thermal effect.


      PubDate: 2015-04-13T01:01:09Z
       
  • Abrasive Wear Resistance of Dual Phase Steels DP980 and DP600
    • Abstract: Publication date: April 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 4
      Author(s): Xiu-lin JI , Ju-yi WANG , Cui-cui JI , Jian-hua ZHAO
      The abrasive wear resistance of dual phase (DP) steels DP980 and DP600 was investigated by using an ASTM rubber wheel abrasion tester. At 2. 40 m • s−1 sliding speed under 19. 9 N load with 180—355 μm abrasive sands, the wear rates of DP980 and DP600 were 1. 01×10−11 and 0. 86×10−11 m3 • m−1, respectively, corresponding to about 1. 9 and 2. 3 times of the relative wear resistance of normal low-carbon steel ASTM A283C. Using directly water quenching from austenitic temperature, the abrasive wear resistance of DP980 samples under 19. 9 N load could be improved by 1. 65 times. The wear rates of DP980 and DP600 samples decreased respectively with increasing sliding speed and abrasive particle size and decreasing applied load. The experimental results reveal that the effect of martensite on the wear resistance not only depends on the volume fraction but also depends on the morphology, distribution and grain size.


      PubDate: 2015-04-13T01:01:09Z
       
  • Influence of Cohesive Zone Shape on Solid Flow in COREX Melter Gasifier by
           Discrete Element Method
    • Abstract: Publication date: April 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 4
      Author(s): Li-hao HAN , Zhi-guo LUO , Heng ZHOU , Zong-shu ZOU , Yu-zhu ZHANG
      Based on the principle of discrete element method (DEM), a 2D slot model of a COREX melter gasifier was established to analyze the influence of cohesive zone shape on solid flow, including mass distribution, velocity distribution, normal force distribution and porosity distribution at a microscopic level. The results show that the cohesive zone shape almost does not affect the particle movement in the upper shaft and deadman shape. The particles in the lower central bottom experience large normal force to support the particles above them, while particles around the raceway and in the fast flow zone exhibit weak force network. The porosity distribution was also examined under three kinds of cohesive zones. Like the velocity distribution, the whole packed bed can be divided into four main regions. With the increase of cohesive zone position, the low porosity region located in the root of cohesive zone increases. And the porosity distribution becomes asymmetric in the case of biased cohesive zone.


      PubDate: 2015-04-13T01:01:09Z
       
  • Softening and Melting Behavior of Ferrous Burden under Simulated Oxygen
           Blast Furnace Condition
    • Abstract: Publication date: April 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 4
      Author(s): Hua-jie ZHANG , Xue-feng SHE , Yi-hua HAN , Jing-song WANG , Fan-bo ZENG , Qing-guo XUE
      The softening and melting behavior of sinter, pellet and mixed burden was researched through high temperature reaction tests under load simulating traditional blast furnace (T-BF) and oxygen blast furnace (OBF) conditions. The results indicated that compared with T-BF, the softening zone of sinter and pellet became wide, but the melting zone became narrow in OBF. The permeabilities of both sinter and pellet were improved in OBF. Under the condition of OBF, the temperature of softening zone of mixed burden was increased by 63 K, but the temperature of melting zone was decreased by 76 K. Therefore, the permeability of material layer was significantly improved. This was mainly caused by the change of the melting behavior of pellet. In addition, the quality of dripping iron in OBF was much better than that of T-BF.


      PubDate: 2015-04-13T01:01:09Z
       
  • Effect of V and N on Microstructures and Properties of Grade-70 Tire Cord
           Steel during Cold Drawing
    • Abstract: Publication date: February 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 2
      Author(s): Hong-yu LIU , Bao-yi WAN , Xiao-yu ZENG , Chong LIN , Hong-jun WANG
      Commercial grade-70 tire cord steel was microalloyed with V and N to explore the possibility of substituting V for C and the effect of V and N on cementite dissolution during cold drawing process. Tensile strength, elongation and torsion laps of cold-drawn wires were determined. Microstructures of secondary phases were studied by transmission electron microscopy (TEM) and energy dispersive spectroscopy (EDS). Saturation magnetization was measured by using a vibrating sample magnetometer (VSM) to evaluate cementite dissolution during cold drawing process. Experimental results showed that with the increase of V content, tensile strength increased, elongation slightly decreased, and the torsion laps of the cold-drawn wires decreased. Results also showed that with the increase of N content, a peak (increasing first and then decreasing) appeared in the tensile strength graph, and an increase of elongation and a decrease of torsion laps of the cold-drawn wires occured. N is soluble in ferrite when its content is low. The increase in the content of N to 82 × 10−6 will result in the precipitation of the V-containing secondary phases. Also, cementite tended to be stable during cold drawing process with the increase of V and N contents. Grade-80 tire cord steel can be replaced by grade-70 tire cord steel microalloyed with 0.086 mass% V.


      PubDate: 2015-02-14T20:01:38Z
       
  • Heat Treatment of a Candidate Material for 700 °C A-USC Power Plants
    • Abstract: Publication date: February 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 2
      Author(s): Yan CHONG , Zheng-dong LIU , Andy GODFREY , Lu WANG , Wei LIU , Yu-qing WENG
      The preliminary chemical composition optimization and heat treatment parameters of Inconel 740H were investigated systematically. Six heats of experimental alloys (designated as heat 401 to heat 406) with varied chemical compositions were subjected to standard heat treatment at four different solution temperatures. Due to its superior combination of strength, ductility, and toughness together with its minor mechanical property changes at different solution temperatures, heat 405 was chosen as an optimized one to conduct further heat treatment investigations. The evolution of grain size with solution temperature for heat 405 was studied and the optimal solution temperature was determined. After solution treatment at the optimal temperature, four different cooling rates were applied to investigate the effect of cooling rate on the size distribution modal and mean radius of the γ′ precipitates. No bi-modal size distribution of γ′ precipitates was found for all cooling rates and water cooling was recommended for Inconel 740H. In addition, the effect of pre-aging at 800 °C for 16 h on the microstructure of Inconel 740H aged for a long time was studied. It is found that pre-aging at 800 °C would result in bi-modal size distribution of γ′ precipitates after long time aging at 750 °C compared with mono-modal size distribution in samples without pre-aging, which might be caused by the difference in initial size distribution modal before Ostwald ripening of γ′ precipitates in samples with and without pre-aging at 800 °C.


      PubDate: 2015-02-14T20:01:38Z
       
  • Effect of Continuous Annealing on Microstructure and Bake Hardening
           Behavior of Low Carbon Steel
    • Abstract: Publication date: February 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 2
      Author(s): Chun-fu KUANG , Jian WANG , Jun LI , Shen-gen ZHANG , Hua-fei LIU , Hong-lin YANG
      The influences of the heating rate, annealing temperature and soaking time during continuous annealing on the microstructure evolution and bake hardening behavior of the low carbon steel were investigated. After 2% pres-training, bake treatment (180 °C × 20 min) was carried out to measure BH (bake hardening) values. The results showed that, with the increase of the annealing temperature, the grain size increased except for annealing in the intercritical region. Furthermore, the BH value increased and the mean grain size reduced with increasing the heating rate from 5 to 80 °C/s. The BH value was very low before complete recrystallization. After a significant decrease from 630 to 720 °C, the BH value enhanced when the steel was annealed at 750 °C. With the increase of the soaking time from 20 to 100 s, the BH value reduced linearly due to the segregation of solute C atoms.


      PubDate: 2015-02-14T20:01:38Z
       
  • Amorphous FeNiCoCuSiBCr Alloys with Superior Direct Current Tolerant
           Characteristics
    • Abstract: Publication date: February 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 2
      Author(s): Xiao-rong WU , De-ren LI , Zhun LI , Zhi-chao LU
      Amorphous Fe62-x Ni19Co x Cu0.1 Si3.8 B14 Cr1.1 (x = 0, 1, 5, 10) ribbons were annealed under magnetic field and tensile stress, respectively, and their magnetic properties were investigated. Fe73.5 Cu1 Nb3 Si15.5 B7 and Fe66 Ni10-Cu1 Nb3 Si11 B9 nanocrystalline alloy ribbons were also fabricated for comparison. Excellent DC tolerant property was obtained in the amorphous FeNiCoCuSiBCr ribbons after thermomagnetic treatment and the constant permeable property was improved with increasing Co content. The relative permeability was constant up to the DC bias field of approximately 6 × 10−4, 9 × 10−4, and 10 × 10−4 T and the values of relative permeability μr were 1650, 1200, and 1000 with the Co content being 0, 5 at. %, and 10 at. %, respectively. Besides, stress-annealed FeNiCoCuSiBCr alloy ribbons were proved to exhibit positive saturation magnetostriction constant λs.


      PubDate: 2015-02-14T20:01:38Z
       
  • Austenite Grain Refinement by Reverse α′ → γ
           Transformation in Metastable Austenitic Manganese Steel
    • Abstract: Publication date: February 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 2
      Author(s): Jia-tao ZHANG , Yu-guang ZHAO , Juan TAN , Xiao-feng XU
      Microstructure of metastable austenitic manganese steel after reverse transformation treatment was investigated using optical microscopy, X-ray diffraction (XRD), electrical resistivity and hardness testing. Austenite grain refinement was successfully achieved by a two-step heat treatment. First, martensite was produced by cooling the solution-treated samples to −196 °C. Then, the deep cryogenic treated samples were heated to 850 °C upon slow or rapid heating. The mean size of original austenite grain was about 400 μm. But the mean size of equiaxed reversion austenite was refined to 50 μm. Microstructure evolution and electrical resistivity change showed that martensite plates underwent tempering action upon slow heating, and the residual austenite was decomposed, resulting in the formation of pearlite nodules at the austenite grains boundaries. The refinement mechanism upon slow heating is the diffusion-controlled nucleation and growth of austenite. However, the reverse transformation upon rapid heating was predominated by displacive manner. The residual austenite was not decomposed. The plate a-phase was carbon-supersaturated until the starting of reverse transformation. The reverse transformation was accompanied by surface effect, resulting in the formation of plate austenite with high density dislocations. The refinement mechanism upon rapid heating is the recrystallization of displacive reversed austenite.


      PubDate: 2015-02-14T20:01:38Z
       
  • Effect of Temperature on Microstructure and Deformation Mechanism of
           Fe-30Mn-3Si-4Al TWIP Steel at Strain Rate of 700 s−1
    • Abstract: Publication date: February 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 2
      Author(s): Zhi-ping XIONG , Xue-ping REN , Jian SHU , Zhe-lei WANG , Wei-ping BAO , Shu-xia LI
      As twinning-induced plasticity (TWIP) steel is one potential material for shaped charge liner due to the combination of high strength and high plasticity, deformation mechanism at high strain rate and high temperature is required to study. Compression experiments of Fe-30Mn-3Si-4Al TWIP steel were conducted using a Gleeble-1500 thermal simulation machine and a split-Hopkinson pressure bar (SHPB) between 298 and 1073 K at strain rates of 10−3 and 700 s−1, respectively. Microstructures were observed using optical microscopy (OM) and transmission electron microscopy (TEM). Results show that flow stress and densities of deformation twins and dislocations decrease with increasing deformation temperature at strain rates of 10−3 and 700 s−1. The stack fault energy (SFE) values (Γ) of Fe-30Mn-3Si-4Al TWIP steel at different temperatures were calculated using thermodynamic data. Based on corresponding microstructures, it can be inferred that at 700 s−1, twinning is the main deformation mechanism at 298–573 K for 30 mJ/m2⩽Γ⩽63 mJ/m, while dislocation gliding is the main deformation mechanism above 1073 K for Γ⩾ 145 mJ/m2. In addition, with increasing strain rate from 10−3 to 700 s−1, the SFE range of twinning is enlarged and the SEF value of twinning becomes higher.


      PubDate: 2015-02-14T20:01:38Z
       
  • In-situ Corrosion Characterization of API X80 Steel and Its Corresponding
           HAZ Microstructures in an Acidic Environment
    • Abstract: Publication date: February 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 2
      Author(s): Li-wei WANG , Xiao-gang LI , Cui-wei DU , Peng ZHANG , Yi-zhong HUANG
      During heat treatment processing, microstructures of heat affected zone (HAZ) were formed in X80 pipeline steel. After observation by optical microscopy, scanning electron microscopy and transmission electron microscopy, microstructure of the as-received X80 steel was confirmed to be acicular ferrite, while the microstructures of quenched, normalized and annealed X80 steels were lath bainite, granular ferrite and quasi-polygonal ferrite, respectively. After immersion in the simulated acidic soil solution for 48 h, corrosion rates of these four steels were determined by mass loss measurements and corrosion products were examined by Raman spectroscopy and X-ray photoelectron spectroscopy. Scanning vibrating electrode technique was used to characterize the micro-galvanic corrosion behaviors of the synthetic bimetallic electrodes which were formed by coupling each of the simulated HAZ microstructures with the as-received steel in direct physical and electric contact. It is demonstrated that the as-received steel acts as cathode in the as-received/quenched and as-received/normalized couples, while the annealed steel acts as cathode when coupling with the as-received steel. The distinction of current density between the galvanic couples reduces with prolonging the immersion time.


      PubDate: 2015-02-14T20:01:38Z
       
  • Microstructure Variation of Pellets Containing Ferrous Dust during
           Carbonation Consolidation
    • Abstract: Publication date: February 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 2
      Author(s): Yan SHI , Shi-meng LIU , Chang-qing HU , Yu-zhu ZHANG
      The carbonation and microstructure characteristics of pellets containing ferrous dusts were investigated during carbonation consolidation at different reaction temperatures and CO2 partial pressures. The results indicated that green pellets had loose and network supporting structure with initial strength, and large cracks and pores existed in the pellets. The carbonation reaction was controlled by interfacial chemical reaction at the initial fast stage, which limited diffusion and thus caused the reaction rate to decrease. With increasing reaction temperature and CO2 partial pressure, the conversion rates of CaO and the number of microcrystalline CaCO3 particles increased, and the volume expansion of CaCO3 led to a decrease in the open porosity, average pore size and specific surface area of the pellets. Micro-pores were occluded, and the number of smaller pores (diameter less than 50 nm) increased, thereby resulting in the more compact and uniform structure of carbonated pellets. Simultaneously, the dense structure prevented CO2 diffusion into the product layer, affecting the increase in carbonation conversion rate.


      PubDate: 2015-02-14T20:01:38Z
       
  • Characteristics and Mechanism of Reduction and Smelting-separation Process
           of Copper Slag
    • Abstract: Publication date: February 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 2
      Author(s): Jun ZHANG , Yuan-hong QI , Ding-liu YAN , Xiang-li CHENG , Peng HE
      The characteristics and mechanism of the reduction and smelting-separation process of the copper slag were studied by investigating the variation rule of metallization ratio, yield as well as carbon content of iron nuggets. The formation of molten slag is necessary for slag-iron separation, and iron is in half-molten state during smelting-separation process, the carbon content of which is about 1.25%. Carburization occurs through direct contact between carbon and iron in essence, no matter in solid or molten state. The carburization rate is slow below 1200 °C, which is inhibited by the existence of slag. Residual FeO in molten slag tends to form fayalite with SiO2 in the copper slag, which is the root cause for the low melting temperature of copper slag. The addition of CaO improves the reducibility of the copper slag, but Al2O3 addition has no obvious effect. The melting temperature of slag affects the carburization extent in solid state, while the content of FeO in molten slag affects that in molten state, both of which co-determine the carbon content in iron nuggets.


      PubDate: 2015-02-14T20:01:38Z
       
  • Reduction Behavior of Pellet under Simulated Oxygen Blast Furnace
           Condition
    • Abstract: Publication date: February 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 2
      Author(s): Hua-jie ZHANG , Jing-song WANG , Xiu-wei AN , Xiao-jian ZUO , Qing-guo XUE
      The reduction behavior of pellet was researched through the programming apparatus under simulated conditions of oxygen blast furnace (OBF) and traditional blast furnace (T-BF). The results indicated that compared with traditional blast furnace, the reduction starting temperature of pellet decreased by 60 °C under oxygen blast furnace condition. The reduction degree of pellet could almost reach 100% under oxygen blast furnace condition when the temperature reached 1100 °C, whereas it was only 82. 49% in traditional blast furnace. The content of carbon in pellet of oxygen blast furnace was about 5 times more than that of traditional blast furnace. In addition, the microstructure at the periphery and core of pellets after reaction was characterized by means of SEM and EDS.


      PubDate: 2015-02-14T20:01:38Z
       
  • Prediction and Control of Thermal Scratch Defect on Surface of Strip in
           Tandem Cold Rolling
    • Abstract: Publication date: February 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 2
      Author(s): Jin-shan CHEN , Chang-sheng LI
      The thermal scratch significantly influences the surface quality of the cold rolled stainless steel strip. In order to establish a precise mathematical model of oil film thickness in deformation zone, the lubrication in cold rolling process of B443NT stainless steel strip was studied in the laboratory. According to the principle of statistics, a mathematical model of critical oil film thickness in deformation zone for thermal scratch was built, with fitting and regression analytical method, and then based on temperature comparison method, the criterion for deciding thermal scratch defect was put forward. Storing and calling data through SQL Server 2005, a software on thermal scratch control was developed in the Microsoft Visual Studio 2008 environment by MFC technique for stainless steel in tandem cold rolling, and then it was used into the practical production. Statistical results demonstrated that the hit rate of thermal scratch arrives at 91.47%, the occurrence rate of thermal scratch is decreased by 87.81%, and rolling speed is increased by 7.3%. The developed software is of significance to the control of products quality of stainless steel strips, and the analysis and solution to the problem of thermal scratch defects in tandem cold rolling.


      PubDate: 2015-02-14T20:01:38Z
       
  • Research Progress and Development Tendency of Nitrogen-alloyed Austenitic
           Stainless Steels
    • Abstract: Publication date: February 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 2
      Author(s): Yu-ping LANG , Hua-peng QU , Hai-tao CHEN , Yu-qing WENG
      Research progress on nitrogen-alloyed austenitic stainless steels was expounded through the development of steel grades. In addition, hot topics in the research of nitrogen-alloyed austenitic stainless steels were discussed, including the solubility of nitrogen, brittle-ductile transition, and welding. On this basis, it was proposed that the future development tendency of nitrogen-alloyed austenitic stainless steels lied in the three fields of high-performance steels, resource-saving steels, and biologically friendly steels. The problems encountered during the research of nitrogen-alloyed austenitic stainless steels were discussed.


      PubDate: 2015-02-14T20:01:38Z
       
  • Technology Development for Controlling Slab Transverse Corner Crack of
           Typical Micro-alloyed Steels
    • Abstract: Publication date: February 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 2
      Author(s): Hui ZHANG , Chun-zheng YANG , Ming-lin WANG , Hong-biao TAO , He-ping LIU , Xue-bing WANG
      A mathematical model for simulating the fluid flow, heat transfer and solidification in the conventional mold and the chamfer mold, together with a finite element stress-strain model in the straightening process of both molds, were established for the typical niobium, vanadium, and titanium micro-alloyed steels. On the basis of both numerical analysis, the mold copper plate with an optimum chamfered shape was designed and applied in industrial tests. The predicted results from numerical simulation of fluid flow, heat transfer and solidification in the conventional mold and the chamfer mold show that the increased chamfered angle leads to an approximately linear increase of the slab surface temperature, but it also causes strong flow near the slab corner. Very small chamfered length can lead to a significant increase of the temperature near the slab corner. However, with further increasing the chamfered length, the temperature of the slab corner increased slightly. The calculated results from the finite element analysis of stress-strain during the straightening process show that at the same slope width, the tangential strain on the slab edges and corners is minimum when the chamfered angle is 30° and 45°, which is only 40% to 46% of rectangular slabs with the same cross-section area. At the same chamfered angle of 30°, when the chamfered length is controlled between 65–85 mm, the tangential strain on the part of the slab edges and corners is relatively smaller. Industrial test results show that the slab corner temperature at straightening segment increases about 100 °C by using chamfer mold compared to the conventional molds. The slab transverse corner cracks have been reduced more than 95% in comparison with those in the conventional mold.


      PubDate: 2015-02-14T20:01:38Z
       
  • Mechanisms of Swelling of Iron Ore Oxidized Pellets in High Reduction
           Potential Atmosphere
    • Abstract: Publication date: January 2015
      Source:Journal of Iron and Steel Research, International, Volume 22, Issue 1
      Author(s): Run-sheng XU , Jian-liang ZHANG , Hai-bin ZUO , Ke-xin JIAO , Zheng-wen HU , Xiang-dong XING
      The influences of the time, temperature and atmosphere on the reduction swelling of oxidized pellets were investigated by single factor experiments. The mechanisms of reduction swelling of oxidized pellets were analyzed and investigated by SEM (scanning electron microscopy) and XRD (X-ray diffractometer) analysis. The results show that the change rules of reduction swelling index of oxidized pellets in different reduction atmospheres are very similar. With the increase of reduction time, the reduction swelling index moves up firstly and then down. When the reduction temperature is above 900 °C, α-quartz turns into α-tridymite, and the transition generates additional volume expansion effect. The reduction swelling index changes faster in H2 atmosphere than in CO atmosphere. Increasing H2 content in the reduction atmosphere is useful to decrease the reduction swelling index, but it is also easy to cause oxidized pellets cracking.


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


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


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


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


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


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


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


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


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


      PubDate: 2015-01-14T20:04:16Z
       
 
 
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