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ENVIRONMENTAL STUDIES (694 journals)            First | 1 2 3 4     

Showing 601 - 378 of 378 Journals sorted alphabetically
Revista Internacional de Ciências     Open Access   (Followers: 1)
Revista Meio Ambiente e Sustentabilidade     Open Access   (Followers: 1)
Revista Metropolitana de Sustentabilidade     Open Access  
Revista Monografias Ambientais     Open Access  
Revista Verde de Agroecologia e Desenvolvimento Sustentável     Open Access   (Followers: 2)
Ring     Open Access   (Followers: 1)
Riparian Ecology and Conservation     Open Access   (Followers: 7)
Rivista di Studi sulla Sostenibilità     Full-text available via subscription   (Followers: 1)
Russian Journal of Ecology     Hybrid Journal   (Followers: 1)
S.A.P.I.EN.S     Open Access   (Followers: 2)
Safety Science     Hybrid Journal   (Followers: 32)
San Francisco Estuary and Watershed Science     Open Access  
SAR and QSAR in Environmental Research     Hybrid Journal   (Followers: 1)
Saúde e Meio Ambiente : Revista Interdisciplinar     Open Access  
Scandinavian Journal of Work, Environment & Health     Partially Free   (Followers: 12)
Science of The Total Environment     Hybrid Journal   (Followers: 27)
Sciences Eaux & Territoires : la Revue du Cemagref     Open Access  
Scientific Journal of Environmental Sciences     Open Access   (Followers: 1)
Sepsis     Hybrid Journal  
Smart Grid and Renewable Energy     Open Access   (Followers: 8)
Social and Environmental Accountability Journal     Hybrid Journal   (Followers: 3)
Soil and Sediment Contamination: An International Journal     Hybrid Journal   (Followers: 2)
Soil and Tillage Research     Hybrid Journal   (Followers: 8)
SourceOCDE Environnement et developpement durable     Full-text available via subscription   (Followers: 1)
SourceOECD Environment & Sustainable Development     Full-text available via subscription  
South Pacific Journal of Natural and Applied Sciences     Hybrid Journal  
Southern Forests : a Journal of Forest Science     Hybrid Journal   (Followers: 5)
Sriwijaya Journal of Environment     Open Access  
Stochastic Environmental Research and Risk Assessment     Hybrid Journal   (Followers: 4)
Strategic Behavior and the Environment     Full-text available via subscription   (Followers: 2)
Strategic Planning for Energy and the Environment     Hybrid Journal   (Followers: 4)
Studies in Conservation     Hybrid Journal   (Followers: 12)
Studies in Environmental Science     Full-text available via subscription   (Followers: 5)
Sustainability     Open Access   (Followers: 21)
Sustainability in Environment     Open Access   (Followers: 2)
Sustainability of Water Quality and Ecology     Hybrid Journal   (Followers: 4)
Sustainable Cities and Society     Hybrid Journal   (Followers: 23)
Sustainable Development     Hybrid Journal   (Followers: 16)
Sustainable Development Law & Policy     Open Access   (Followers: 7)
Sustainable Development Strategy and Practise     Open Access  
Sustainable Environment Research     Open Access  
Sustainable Technologies, Systems & Policies     Open Access   (Followers: 7)
TECHNE - Journal of Technology for Architecture and Environment     Open Access   (Followers: 7)
Tecnogestión     Open Access  
Territorio della Ricerca su Insediamenti e Ambiente. Rivista internazionale di cultura urbanistica     Open Access  
The Historic Environment : Policy & Practice     Hybrid Journal   (Followers: 5)
The International Journal on Media Management     Hybrid Journal   (Followers: 5)
Theoretical Ecology     Hybrid Journal   (Followers: 12)
Theoretical Ecology Series     Full-text available via subscription   (Followers: 1)
Toxicologic Pathology     Hybrid Journal   (Followers: 21)
Toxicological & Environmental Chemistry     Hybrid Journal   (Followers: 4)
Toxicological Sciences     Hybrid Journal   (Followers: 12)
Toxicology     Hybrid Journal   (Followers: 19)
Toxicology and Applied Pharmacology     Hybrid Journal   (Followers: 20)
Toxicology and Industrial Health     Hybrid Journal   (Followers: 7)
Toxicology in Vitro     Hybrid Journal   (Followers: 13)
Toxicology Letters     Hybrid Journal   (Followers: 13)
Toxicology Mechanisms and Methods     Hybrid Journal   (Followers: 11)
Toxicon     Hybrid Journal   (Followers: 4)
Toxin Reviews     Hybrid Journal   (Followers: 1)
Trace Metals and other Contaminants in the Environment     Full-text available via subscription   (Followers: 2)
Trace Metals in the Environment     Full-text available via subscription   (Followers: 2)
Transactions on Environment and Electrical Engineering     Open Access  
Transportation Research Part D: Transport and Environment     Hybrid Journal   (Followers: 26)
Transylvanian Review of Systematical and Ecological Research     Open Access  
Trends in Ecology & Evolution     Full-text available via subscription   (Followers: 226)
Trends in Environmental Analytical Chemistry     Hybrid Journal   (Followers: 3)
Trends in Pharmacological Sciences     Full-text available via subscription   (Followers: 26)
Tropicultura     Open Access  
UD y la Geomática     Open Access  
Universidad y Ciencia     Open Access   (Followers: 1)
Urban Studies     Hybrid Journal   (Followers: 57)
Veredas do Direito : Direito Ambiental e Desenvolvimento Sustentável     Open Access  
VertigO - la revue électronique en sciences de l’environnement     Open Access   (Followers: 3)
Villanova Environmental Law Journal     Open Access  
Waste Management & Research     Hybrid Journal   (Followers: 9)
Water Environment Research     Full-text available via subscription   (Followers: 41)
Water International     Hybrid Journal   (Followers: 15)
Water, Air, & Soil Pollution     Hybrid Journal   (Followers: 23)
Water, Air, & Soil Pollution : Focus     Hybrid Journal   (Followers: 9)
Waterlines     Full-text available via subscription   (Followers: 2)
Weather and Forecasting     Full-text available via subscription   (Followers: 18)
Weather, Climate, and Society     Full-text available via subscription   (Followers: 12)
Web Ecology     Open Access   (Followers: 5)
Wetlands     Hybrid Journal   (Followers: 24)
Wilderness & Environmental Medicine     Hybrid Journal   (Followers: 4)
Wildlife Australia     Full-text available via subscription   (Followers: 2)
Wiley Interdisciplinary Reviews - Climate Change     Hybrid Journal   (Followers: 17)
Wiley Interdisciplinary Reviews : Energy and Environment     Hybrid Journal   (Followers: 6)
William & Mary Environmental Law and Policy Review     Open Access   (Followers: 2)
World Environment     Open Access   (Followers: 1)
World Journal of Entrepreneurship, Management and Sustainable Development     Hybrid Journal   (Followers: 6)
World Journal of Environmental Engineering     Open Access   (Followers: 2)
Worldviews: Global Religions, Culture, and Ecology     Hybrid Journal   (Followers: 8)
Zoology and Ecology     Hybrid Journal   (Followers: 5)
气候与环境研究     Full-text available via subscription   (Followers: 1)

  First | 1 2 3 4     

Journal Cover Journal of Iron and Steel Research, International
  [SJR: 0.661]   [H-I: 22]   [7 followers]  Follow
   Full-text available via subscription Subscription journal
   ISSN (Print) 1006-706X
   Published by Elsevier Homepage  [3048 journals]
  • Current development in quantitative phase-field modeling of solidification
    • Authors: Xiang-lei Dong; Hui Xing; Kang-rong Weng; Hong-liang Zhao
      Pages: 865 - 878
      Abstract: Publication date: September 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 9
      Author(s): Xiang-lei Dong, Hui Xing, Kang-rong Weng, Hong-liang Zhao
      The quantitative phase-field simulations were reviewed on the processes of solidification of pure metals and alloys. The quantitative phase-field equations were treated in a diffuse thin-interface limit, which enabled the quantitative links between interface dynamics and model parameters in the quasi-equilibrium simulations. As a result, the quantitative modeling is more effective in dealing with microstructural pattern formation in the large scale simulations without any spurious kinetic effects. The development of the quantitative phase-field models in modeling the formation of microstructures such as dendritic structures, eutectic lamellas, seaweed morphologies, and grain boundaries in different solidified conditions was also reviewed with the purpose of guiding to find the new prospect of applications in the quantitative phase-field simulations.

      PubDate: 2017-09-25T14:11:46Z
      DOI: 10.1016/s1006-706x(17)30129-2
  • Inclusion evolution in 50CrVA spring steel by optimization of refining
    • Authors: Hai-yan Tang; Yong Wang; Guang-hui Wu; Peng Lan; Jia-quan Zhang
      Pages: 879 - 887
      Abstract: Publication date: September 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 9
      Author(s): Hai-yan Tang, Yong Wang, Guang-hui Wu, Peng Lan, Jia-quan Zhang
      In order to control the CaO-Al2O3-SiO2-MgO system inclusions in 50CrVA spring steel in a lower melting temperature region, high temperature equilibrium experiments between steel and slag were performed in the laboratory, under the conditions of the initial slag basicity within 3–7 and the content of Al2O3 between 18–35 mass%, to investigate the formation and evolution of this type of inclusion. The results indicate that the total oxygen content in the steel decreases with the increase of slag basicity and the decrease of Al2O3 content in slags, and CaO-Al2O3-SiO2-MgO inclusions tend to deviate from the low melting point region with the increase of Al2O3 content in slags. The most favorable composition for the refining slag is composed of 51–56 mass% CaO, 9–13 mass% SiO2, 20–25 mass% Al2O3 and 6 mass% MgO. In this case, the inclusions in 50CrVA spring steel are mostly in the low melting point regions, in which their plasticities are expected to improve during steel rolling. The MgO-based inclusions were observed in the steel matrix and the formation mechanism was theoretically and schematically revealed. It is also found that adding around 11 mass% of MgO into the refining slags is beneficial to reducing the refractory corrosion. Further work should be carried out focusing on the evolution rates of MgO-based inclusions.

      PubDate: 2017-09-25T14:11:46Z
      DOI: 10.1016/s1006-706x(17)30130-9
  • Multiphase modeling of fluid dynamic in ladle steel operations under
           non-isothermal conditions
    • Authors: H. Gonzalez; J.A. Ramos-Banderas; E. Torres-Alonso; G. Solorio-Diaz; C.A. Hernández-Bocanegra
      Pages: 888 - 900
      Abstract: Publication date: September 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 9
      Author(s): H. Gonzalez, J.A. Ramos-Banderas, E. Torres-Alonso, G. Solorio-Diaz, C.A. Hernández-Bocanegra
      A numerical simulation was performed to study the flow pattern, mixing time and open-eye slag produced by argon gas injection in an industrial scale steel ladle under non-isothermal conditions. The liquid steel remains 5 min before the injection, and thermal stratification and convective flows were analyzed. Three different sequences in stages employing various argon-gas flow rates were simulated. In the first case, a sequence with the highest flow rates of argon was applied, while in the second and the third sequences, the intermediate and the lowest flow rates of argon gas were used, respectively. For determining the chemistry homogenization, the mixing time was computed and analyzed in all three cases. It was found that the cold steel is located near the walls while the steel with a high temperature is accumulated in the center of the ladle above the argon-gas tuyere. The higher and lower flows promote a faster chemistry homogenization owing to the secondary recirculations that are developed closer to the walls. The results from steel temperature drop show a good concordance with plant trial measurements.

      PubDate: 2017-09-25T14:11:46Z
      DOI: 10.1016/s1006-706x(17)30131-0
  • Thermal and chemical analysis of massive use of hot briquetted iron inside
           basic oxygen furnace
    • Authors: Cosmo Di Cecca; Silvia Barella; Carlo Mapelli; Andrea Gruttadauria; Andrea Francesco Ciuffini; Davide Mombelli; Enrico Bondi
      Pages: 901 - 907
      Abstract: Publication date: September 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 9
      Author(s): Cosmo Di Cecca, Silvia Barella, Carlo Mapelli, Andrea Gruttadauria, Andrea Francesco Ciuffini, Davide Mombelli, Enrico Bondi
      The integrated steelmaking cycle based on the blast furnace-basic oxygen furnace (BOF) route plays an important role in the production of plain and ultra-low carbon steel, especially for deep drawing operations. BOF steelmaking is based on the conversion of cast iron in steel by impinging oxygen on the metal bath at supersonic speed. In order to avoid the addition of detrimental chemical elements owing to the introduction of uncontrolled scrap and in order to decrease environmental impact caused by the intensive use of coke for the production of cast iron, HBI (hot briquetted iron) can be used as a source of metal and a fraction of cast iron. Forty industrial experimental tests were performed to evaluate the viability of the use of HBI in BOF. The experimental campaign was supported by a thermal prediction model and realized through the estimation of the oxidation enthalpy. Furthermore, the process was thermodynamically analyzed based on oxygen potentials using the off-gas composition and the bath temperature evolution during the conversion as reference data.

      PubDate: 2017-09-25T14:11:46Z
      DOI: 10.1016/s1006-706x(17)30132-2
  • Dephosphorization stability of hot metal by double slag operation in basic
           oxygen furnace
    • Authors: Wei Wu; Shi-fan Dai; Yue Liu
      Pages: 908 - 915
      Abstract: Publication date: September 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 9
      Author(s): Wei Wu, Shi-fan Dai, Yue Liu
      Double slag process was adopted to produce low-phosphorus steel from middle-phosphorus hot metal. To achieve a stable dephosphorization operation, conventional process was modified as follows: the blowing time was extended by approximately 1 min by reducing the oxygen supply flow rate; calcium ferrite pellets were added to adjust the slag composition and viscosity; the dumping temperature was lowered by 30–50 °C by the addition of calcium ferrite pellets during the double slag process to prevent phosphorus in the slag from returning to the molten steel; and the bottom-blown gas flow was increased during the blowing process. For 40 heats of comparative experiments, the rate of dephosphorization reached 91% and ranged between 87% and 95%; the phosphorus, sulfur, manganese, and oxygen contents calculated according to the compositions of molten steel and slag as well as the temperature of molten steel at the end-point of the basic oxygen furnace process were similar to the equilibrium values for the reaction between the slag and the steel. Less free calcium oxide and metallic iron were present in the final slag, and the surface of the slag mineral phase was smooth, clear, and well developed, which showed that the slag exhibited better melting effects than that produced using the conventional slag process. A steady phosphorus capacity in the slag and stable dephosphorization effects were achieved.

      PubDate: 2017-09-25T14:11:46Z
      DOI: 10.1016/s1006-706x(17)30133-4
  • Constitutive analysis and optimization on hot working parameters of
           as-cast high Cr ultra-super-critical rotor steel with columnar grains
    • Authors: Zong-ye Ding; Di Zhang; Qiao-dan Hu; Long Zeng; Jian-guo Li
      Pages: 916 - 924
      Abstract: Publication date: September 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 9
      Author(s): Zong-ye Ding, Di Zhang, Qiao-dan Hu, Long Zeng, Jian-guo Li
      Isothermal hot compression tests on the as-cast high-Cr ultra-super-critical rotor steel with columnar grains were carried out in the temperature range from 1223 to 1523 K and at strain rates from 0.001 to 1 s–1. The compression direction was parallel to the longitudinal direction of columnar grains. The constitutive equation based on Arrhenius model was presented, and the processing maps based on the dynamic material model were developed, correlating with microstructure observation. The main softening mechanism was dynamic recovery at 1223 K under strain rates from 0.1 to 1 s–1, whereas it was dynamic recrystallization under other deformation conditions. The constitutive equation modified by strain compensation reasonably predicted the flow stresses. The processing maps and microstructure evolution mechanism schematic indicated that the optimum hot working parameters lay in the zone defined by the temperature range from 1423 to 1473 K and the strain rate range from 0.001 to 1 s–1.

      PubDate: 2017-09-25T14:11:46Z
      DOI: 10.1016/s1006-706x(17)30134-6
  • Evolution of Al2O3 inclusions by cerium treatment in low carbon high
           manganese steel
    • Authors: Hao Li; Yan-chong Yu; Xiang Ren; Shao-hua Zhang; She-bin Wang
      Pages: 925 - 934
      Abstract: Publication date: September 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 9
      Author(s): Hao Li, Yan-chong Yu, Xiang Ren, Shao-hua Zhang, She-bin Wang
      The influence of cerium (Ce) treatment on the morphologies, size and distributions of Al2O3 inclusions in low carbon high manganese steel was investigated by OM, SEM-EDS and theoretical calculation. The results showed that Ce can modify the morphologies and types of Al2O3 inclusions. After Ce treatment, the irregular Al2O3 inclusions were replaced by smaller and dispersive spherical cerium oxysulfides. The effects of treatment time and Ce content on the evolution of Al2O3 inclusions were examined. It indicated that Al2O3 inclusions were wrapped by rare earth inclusions to form a ring like shape Ce-enriched band around the inclusions. Model was established to elucidate the evolution mechanism of Al2O3 inclusions. Evolution kinetics of inclusions was discussed qualitatively to analyze the velocity controlled step. It was found that diffusion of Ce3+ and Al3+ in solid inclusion core and the formed intermediate layer would be the limited step during the evolution process.

      PubDate: 2017-09-25T14:11:46Z
      DOI: 10.1016/s1006-706x(17)30135-8
  • Cavitation erosion behavior of CLAM steel weld joint in liquid
           lead-bismuth eutectic alloy
    • Authors: Yu-cheng Lei; Xiao-kai Guo; Hong-xia Chang; Tian-qing Li; Qiang Zhu; Gang Chen; Long-ren Xiao
      Pages: 935 - 942
      Abstract: Publication date: September 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 9
      Author(s): Yu-cheng Lei, Xiao-kai Guo, Hong-xia Chang, Tian-qing Li, Qiang Zhu, Gang Chen, Long-ren Xiao
      The cavitation erosion of weld joint and base metal of China low activation martensitic (CLAM) steel in liquid lead-bismuth eutectic alloy (LBE) at 550 °C was investigated to simulate the cavitation erosion of the first wall and the nuclear main pump impeller in the accelerator driven sub-critical system (ADS). A suit of ultrasonic cavitation facility was self-designed to study the cavitation erosion. By studying the surface micro topography, roughness and mean pit depth of the tested specimens, it was found that some crater clusters and large scale cracks appeared on the tested specimen surface after the formation of numerous single craters, and the base metal exhibited much better cavitation erosion resistance than the weld bead due to the difference in their mechanical properties and microstructures. In addition, by comparing the results of static corrosion and cavitation erosion, it could be concluded that the cavitation erosion and the dissolution and oxidation corrosion in liquid LBE would accelerate mutually.

      PubDate: 2017-09-25T14:11:46Z
      DOI: 10.1016/s1006-706x(17)30136-x
  • Effect of artificial tribological layer on sliding wear behavior of H13
    • Authors: Zhen Cao; Shu-qi Wang; Ke-zhi Huang; Bo Zhang; Guo-hong Wen; Qiu-yang Zhang; Lan Wang
      Pages: 943 - 949
      Abstract: Publication date: September 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 9
      Author(s): Zhen Cao, Shu-qi Wang, Ke-zhi Huang, Bo Zhang, Guo-hong Wen, Qiu-yang Zhang, Lan Wang
      An artificial tribological layer was formed on the worn surface during sliding, through supplying MoS2, Fe2O3 or their equiponderant mixtures onto the sliding interface of H13/GCr15 steels. The effect of this tribological layer on the wear behavior of H13 steel was studied. The worn surfaces and subsurfaces of H13 steel were thoroughly characterized by using X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS); the wear mechanisms were explored. The research results demonstrated that tribological layer did not exist during sliding of H13 steel with no additive, but it formed with the addition of MoS2, Fe2O3 or their equiponderant mixtures. When there was no tribological layer, the wear rate rapidly increased with an increase of the load. In this case, adhesive and abrasive wear prevailed. As the additives were supplied, the artificial tribological layer was observed to be immediately formed and stably existed on worn surfaces. This tribological layer presented an obvious protective function from wear and friction. Hence, the wear rate and friction coefficient were significantly decreased. MoS2 as tribological layer seemed to present more obvious protective function than Fe2O3. By supplying their mixture, the artificial tribological layer possessed not only the load-carrying capacity of Fe2O3, but also the lubricative capacity of MoS2. These two simultaneous capacities could improve the friction and wear properties of H13 steel further.

      PubDate: 2017-09-25T14:11:46Z
      DOI: 10.1016/s1006-706x(17)30137-1
  • Effect of tempering temperature on strain hardening exponent and flow
           stress curve of 1000 MPa grade steel for construction machinery
    • Authors: Yang Yun; Qing-wu Cai; Bao-sheng Xie; Shuang Li
      Pages: 950 - 956
      Abstract: Publication date: September 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 9
      Author(s): Yang Yun, Qing-wu Cai, Bao-sheng Xie, Shuang Li
      To study the effect of tempering temperature on strain hardening exponent and flow stress curve, one kind of 1000 MPa grade low carbon bainitic steel for construction machinery was designed, and the standard uniaxial tensile tests were conducted at room temperature. A new flow stress model, which could predict the flow behavior of the tested steels at different tempering temperatures more efficiently, was established. The relationship between mobile dislocation density and strain hardening exponent was discussed based on the dislocation-stress relation. Arrhenius equation and an inverse proportional function were adopted to describe the mobile dislocation, and two mathematical models were established to describe the relationship between tempering temperature and strain hardening exponent. Nonlinear regression analysis was applied to the Arrhenius type model, hence, the activation energy was determined to be 37.6 kJ/mol. Moreover, the square of correlation coefficient was 0.985, which indicated a high reliability between the fitted curve and experimental data. By comparison with the Arrhenius type curve, the general trend of the inverse proportional fitting curve was coincided with the experimental data points except of some fitting errors. Thus, the Arrhenius type model can be adopted to predict the strain hardening exponent at different tempering temperatures.

      PubDate: 2017-09-25T14:11:46Z
      DOI: 10.1016/s1006-706x(17)30138-3
  • Effect of squeeze casting process on microstructures and flow stress
           behavior of Al-17.5Si-4Cu-0.5Mg alloy
    • Authors: Yuan-ji Shi; Lan-ji Liu; Lei Zhang; Li-jun Zhang; Li Zheng; Run-xia Li; Bao-yi Yu
      Pages: 957 - 965
      Abstract: Publication date: September 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 9
      Author(s): Yuan-ji Shi, Lan-ji Liu, Lei Zhang, Li-jun Zhang, Li Zheng, Run-xia Li, Bao-yi Yu
      The effects of squeeze casting process on microstructure and flow stress behavior of Al-17.5Si-4Cu-0.5 Mg alloy were investigated and the hot-compression tests of gravity casting and squeeze casting alloy were carried out at 350–500 °C and 0.001–5 s–1. The results show that microstructures of Al-17.5Si-4Cu-0.5 Mg alloys were obviously improved by squeeze casting. Due to the decrease of coarse primary Si particles, soft α-Al dendrite as well as the fine microstructures appeared, and the mechanical properties of squeeze casting alloys were improved. However, when the strain rate rises or the deformation temperature decreases, the flow stress increases and it was proved that the alloy is a positive strain rate sensitive material. It was deduced that compared with the gravity casting alloy, squeeze casting alloy (solidified at 632 MPa) is more difficult to deform since the flow stress of squeeze casting alloy is higher than that of gravity casting alloy when the deformation temperature exceeds 400 °C. Flow stress behavior of Al-17.5Si-4Cu-0.5Mg alloy can be described by a hyperbolic sine form with Zener-Hollomon parameter, and the average hot deformation activation energy Q of gravity casting alloy and squeeze casting alloy is 278. 97 and 308.77 kJ/mol, respectively.

      PubDate: 2017-09-25T14:11:46Z
      DOI: 10.1016/s1006-706x(17)30139-5
  • Simulation study on heat-affected zone of high-strain X80 pipeline steel
    • Authors: Ying Ci; Zhan-zhan Zhang
      Pages: 966 - 972
      Abstract: Publication date: September 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 9
      Author(s): Ying Ci, Zhan-zhan Zhang
      The microstructure evolution and impact-toughness variation of heat-affected zone (HAZ) in X80 high-strain pipeline steel were investigated via a welding thermal-simulation technique, Charpy impact tests, and scanning electron microscopy observations under different welding heat inputs and peak temperatures. The results indicate that when heat input was between 17 and 25 kJ · cm–1, the coarse-grained heat-affected zone showed improved impact toughness. When the heat input was increased further, the martensite-austenite (M-A) islands transformed from fine lath into a massive block. Therefore, impact toughness was substantially reduced. When the heat input was 20 kJ · cm–1 and the peak temperature of the first thermal cycle was between 900 and 1300 °C, a higher impact toughness was obtained. When heat input was 20 kJ · cm–1 and the peak temperature of the first thermal cycle was 1300 °C, the impact toughness value at the second peak temperature of 900 °C was higher than that at the second peak temperature of 800 °C because of grain refining and uniformly dispersed M-A constituents in the matrix of bainite.

      PubDate: 2017-09-25T14:11:46Z
      DOI: 10.1016/s1006-706x(17)30140-1
  • Effect of dissolved niobium on eutectoid transformation behavior
    • Authors: Qi-long Yong; Zheng-yan Zhang; Xin-jun Sun; Jian-chun Cao; Zhao-dong Li
      Pages: 973 - 978
      Abstract: Publication date: September 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 9
      Author(s): Qi-long Yong, Zheng-yan Zhang, Xin-jun Sun, Jian-chun Cao, Zhao-dong Li
      The effect of dissolved niobium on the eutectoid transformation behavior in near-eutectoid high-carbon steels has been studied. Dissolved niobium is important in the eutectoid transformation behavior. It increases the eutectoid carbon content significantly (by ˜0.0477% per 0.00001% dissolved niobium), increases the hardenability of steel markedly, yields finer, more uniform, polygonal proeutectoid ferrite, induces a transition in morphology of eutectoid cementite from lamellar to somewhat spheroidal, and increases the misorientation angle of pearlite colonies from being focused near 0° to near 60°.

      PubDate: 2017-09-25T14:11:46Z
      DOI: 10.1016/s1006-706x(17)30141-3
  • Current status and development trends of innovative blast furnace
           ironmaking technologies aimed to environmental harmony and operation
    • Authors: Hong-tao Wang; Wei Zhao; Man-sheng Chu; Cong Feng; Zheng-gen Liu; Jue Tang
      Pages: 751 - 769
      Abstract: Publication date: August 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 8
      Author(s): Hong-tao Wang, Wei Zhao, Man-sheng Chu, Cong Feng, Zheng-gen Liu, Jue Tang
      Blast furnace (BF) ironmaking is dominant for reducing pollution emission and energy consumption in iron and steel industry. Under the increasingly strict environmental pressure, some innovative technologies of BF ironmaking for environmental protection have been developed and applied in actual operating facilities. The current state of BF ironmaking in Europe, America, Japan, and China were briefly overviewed. Moreover, some innovative BF ironmaking technologies aiming at environmental harmony and operation intellectualization in the world, such as waste gas recycling sintering, BF operation with coke oven gas injection, ferro-coke, lime coating coke, BF visualization and intellectualization, were roundly summarized. Finally, some discussion on the technologies was carried out and the development trends of BF ironmaking were pointed out. The review could provide references and supports for the progress of environment-friendly technologies of BF ironmaking, thereby promoting their practical applications and achieving sustainable development of BF ironmaking, especially for Chinese ironmaking industry.

      PubDate: 2017-09-01T02:10:30Z
      DOI: 10.1016/s1006-706x(17)30115-2
  • Analysis of energy consumption for lump coal degradation in melting
    • Authors: Qi-hang Liu; Xiao-ming Li; Jun-xue Zhao
      Pages: 770 - 777
      Abstract: Publication date: August 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 8
      Author(s): Qi-hang Liu, Xiao-ming Li, Jun-xue Zhao
      The volume hypothesis, a theory about the energy scale of comminution, was adopted to analyze the degradation behavior of lump coal under different heating time. The breakage energy of chars was determined by a compression test, and the results show that the ultimate strength of chars decreased at the early stage during the heating process, resulting in a decrease of the char breakage energy. At the late stage during the heating process, the char breakage energy increased with the increase of heating time. The power consumption coefficients C K of different chars were determined by a drum experiment, and then the char degradation behavior under different power consumptions was predicted. In addition, a gasification experiment was conducted to determine the gasification activation energy (with CO2) of lump coal heated for different time. The results show that the gasification activation energy increased greatly at the early stage during the heating process, which showed opposite change to the breakage energy of chars. Furthermore, the internal temperature and heat changes of the bonded coal briquette were calculated by using an unsteady heat conduction equation. The large difference between the surface and the center temperatures of coal and the large amount of heat absorption at the early stage during the heating process may have a negative effect on the breakage energy of chars.

      PubDate: 2017-09-01T02:10:30Z
      DOI: 10.1016/s1006-706x(17)30116-4
  • Medium oxygen enriched blast furnace with top gas recycling strategy
    • Authors: Wei Zhang; Zheng-liang Xue; Ju-hua Zhang; Wei Wang; Chang-gui Cheng; Zong-shu Zou
      Pages: 778 - 786
      Abstract: Publication date: August 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 8
      Author(s): Wei Zhang, Zheng-liang Xue, Ju-hua Zhang, Wei Wang, Chang-gui Cheng, Zong-shu Zou
      Top gas recycling oxygen blast furnace (TGR-OBF) process is a promising ironmaking process. The biggest challenge of the TGR-OBF in operation is the dramatic decrease of top gas volume (per ton hot metal), which once led to hanging-up and shutdowns in practice of the Toulachermet. In order to avoid this weakness, the strategy of medium oxygen blast furnace was presented. The maneuverable zone of the TGR-OBF was determined by the top gas volume, which should not be far from the data of the traditional blast furnace. The deviation of ±12.5% was used, and then the maneuverable blast oxygen content is from 0.30 to 0.47 according to the calculation. The flame temperature and the top gas volume have no much difference compared to those of the traditional blast furnace. The minimum carbon consumption of 357 kg per ton hot metal in the maneuverable zone occurs at the oxygen content of 0.30 (fuel saving of 14%). In the unsteady evolution, the N2 accumulation could approach nearly zero after the recycling reached 6 times. Thus far, some TGR-OBF industrial trials have been carried out in different countries, but the method of medium oxygen enriched TGR-OBF has not been implemented, because the accumulation of N2 was worried about. The presented strategy of medium oxygen enriched TGR-OBF is applicable and the strategy with good operational performance is strongly suggested as a forerunner of the full oxygen blast furnace.

      PubDate: 2017-09-01T02:10:30Z
      DOI: 10.1016/s1006-706x(17)30117-6
  • Springback behavior of tailor rolled blank in U-shape forming
    • Authors: Ri-huan Lu; Xiang-hua Liu; Shou-dong Chen; Lu Feng; Xian-lei Hu; Li-zhong Liu
      Pages: 787 - 794
      Abstract: Publication date: August 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 8
      Author(s): Ri-huan Lu, Xiang-hua Liu, Shou-dong Chen, Lu Feng, Xian-lei Hu, Li-zhong Liu
      The springback of tailor rolled blanks with quenching and partitioning steels was investigated. In order to find out the springback behavior and related influence factors for the novel sheets, both experimental and simulation methods have been used to compare and analyze the springback characteristics of equal thickness blanks and tailor rolled blanks in U-channel forming. From the results, the overall springback angles of tailor rolled blanks at thin and thick sides are respectively 106. 79° and 99. 705°, which are both lower than those of the corresponding equal thickness blanks. Due to the existence of the thickness transition zone, the stress distribution in thin and thick sides of blanks is changed. The location of dangerous region in thin side of tailor rolled blanks is closer to the end of side, and the thick side moved to the middle of straight wall, which are different with the equal thickness blanks. Afterwards, the released quantitles of tangential stress and strain per unit section of blank are adopted to calculate relative springback angles and give novel evaluation criteria for qualitatively analyzing the amount of springback angles. By comparing the results, it shows that the tangential strain method is more suitable for the actual situation.

      PubDate: 2017-09-01T02:10:30Z
      DOI: 10.1016/s1006-706x(17)30118-8
  • Robust multi-objective optimization of rolling schedule for tandem cold
           rolling based on evolutionary direction differential evolution algorithm
    • Authors: Yong Li; Lei Fang
      Pages: 795 - 802
      Abstract: Publication date: August 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 8
      Author(s): Yong Li, Lei Fang
      According to the actual requirements, profile and rolling energy consumption are selected as objective functions of rolling schedule optimization for tandem cold rolling. Because of mechanical wear, roll diameter has some uncertainty during the rolling process, ignoring which will cause poor robustness of rolling schedule. In order to solve this problem, a robust multi-objective optimization model of rolling schedule for tandem cold rolling was established. A differential evolution algorithm based on the evolutionary direction was proposed. The algorithm calculated the horizontal angle of the vector, which was used to choose mutation vector. The chosen vector contained converging direction and it changed the random mutation operation in differential evolution algorithm. Efficiency of the proposed algorithm was verified by two benchmarks. Meanwhile, in order to ensure that delivery thicknesses have descending order like actual rolling schedule during evolution, a modified Latin Hypercube Sampling process was proposed. Finally, the proposed algorithm was applied to the model above. Results showed that profile was improved and rolling energy consumption was reduced compared with the actual rolling schedule. Meanwhile, robustness of solutions was ensured.

      PubDate: 2017-09-01T02:10:30Z
      DOI: 10.1016/s1006-706x(17)30119-x
  • Surface microstructure control of microalloyed steel during slab casting
    • Authors: Li-jun Xu; Shu-lan Zhang; Chun-gen Qiu; Sheng-tao Qiu; Xing-zhong Zhang
      Pages: 803 - 810
      Abstract: Publication date: August 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 8
      Author(s): Li-jun Xu, Shu-lan Zhang, Chun-gen Qiu, Sheng-tao Qiu, Xing-zhong Zhang
      Lots of work has been done to investigate slab surface microstructure evolution during continuous casting in order to improve hot ductility and avoid transverse cracks. The slab surface microstructure after continuous casting was characterized by optical microscopy, and the precipitation behavior was investigated by transmission electron microscopy. At the same time, the mechanical properties of the slabs were measured using a Gleeble 1500D thermal simulator and the transformation temperatures were examined by means of a thermal dilatometer. The experimental results show that homogeneous microstructure without film-like ferrites and chain-like precipitates at grain boundary can be obtained through surface intensive cooling and transverse cracks do not occur on the slab surface. For the experimental steel, fine ferrite can form at slab surface when the water flow rate is larger than 1560 L/min at vertical section. As the distance to surface increases, microstructure turned to ferrite and pearlite. Moreover, nano-size carbonitrides precipitated in the ferrite grain and the size was larger at the junction of the dislocations. The mechanical experiment results show that the hot ductility of the sample deformed at 650 °C was better than that of the sample deformed at 750 °C. The reason is that film-like ferrite formed at the grain boundary in the sample deformed at 750 °C. Thus, the slab must be cooled quickly below A r3 to prevent the occurrence of film-like ferrite and transverse cracks on the slab surface during casting.

      PubDate: 2017-09-01T02:10:30Z
      DOI: 10.1016/s1006-706x(17)30120-6
  • Effect of α phase on fatigue crack growth of Ti-6242 alloy
    • Authors: Hang-wei Zhou; Hui-qun Liu; Dan-qing Yi; Yu Xiao; Xiao-long Zhao; Jian Wang; Qi Gao
      Pages: 811 - 822
      Abstract: Publication date: August 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 8
      Author(s): Hang-wei Zhou, Hui-qun Liu, Dan-qing Yi, Yu Xiao, Xiao-long Zhao, Jian Wang, Qi Gao
      Fatigue crack growth as a function of a phase volume fraction in Ti-6Al-2Sn-4Zr-2Mo (Ti-6242) alloy was investigated using fatigue testing, optical microscopy, scanning electron microscopy, and transmission electron microscopy. The α+β annealing treatments with different solid solution temperatures and cooling rates were conducted in order to tailor microstructure with different a phase features in the Ti-6242 alloy, and fatigue crack growth mechanism was discussed after detailed microstructure characterization. The results showed that fatigue crack growth rate of Ti-6242 alloy decreased with the decrease in volume fraction of the primary α phase (αp). Samples with a large-sized a grain microstructure treated at high solid solution temperature and slow cooling rate have lower fatigue crack growth rate. The appearance of secondary a phase (αs) with the increase of solid solution temperature led to crack deflection. Moreover, a fatigue crack growth transition phenomenon was observed in the Paris regime of Ti-6242 alloy with 29.8% αp (typical bi-modal microstructure) and large-sized a grain microstructure, owing to the change of fatigue crack growth mechanism.

      PubDate: 2017-09-01T02:10:30Z
      DOI: 10.1016/s1006-706x(17)30121-8
  • Tribological performance of uncoated and TiCN-coated D2, M2 and M4 steels
           under lubricated condition
    • Authors: Luis Daniel Aguilera Camacho; Santos García Miranda; Karla Judith Moreno
      Pages: 823 - 829
      Abstract: Publication date: August 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 8
      Author(s): Luis Daniel Aguilera Camacho, Santos García Miranda, Karla Judith Moreno
      Hard coatings are used to improve the wear resistance of metals which largely depends on adhesion between substrate and coating. The wear and friction behavior of uncoated and TiCN-coated D2, M2 and M4 steels were evaluated by a pin-on-disk test under lubricated conditions. In order to evaluate the influence of lubricant on wear performance, dry friction tests were also performed. The results showed that friction coefficients were very similar for both uncoated and TiCN-coated steels. Under lubricated conditions, the uncoated D2 tool steel exhibited the lowest friction coefficient, but the TiCN-coated D2 steel presented the smallest wear rate. Abrasion was the main wear mechanism in all the tribocouples. Additionally, microhardness measurements were carried out, finding an influence of the steel substrate on the hardness of the coatings. Besides, adhesion test was conducted, suggesting a good adhesion of class 1 between substrates and TiCN coatings.

      PubDate: 2017-09-01T02:10:30Z
      DOI: 10.1016/s1006-706x(17)30122-x
  • Thermal stability of retained austenite and mechanical properties of
           medium-Mn steel during tempering treatment
    • Authors: Xiao-li Zhao; Yong-jian Zhang; Cheng-wei Shao; Wei-jun Hui; Han Dong
      Pages: 830 - 837
      Abstract: Publication date: August 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 8
      Author(s): Xiao-li Zhao, Yong-jian Zhang, Cheng-wei Shao, Wei-jun Hui, Han Dong
      The thermal stability of retained austenite (RA) and the mechanical properties of the quenched and intercritical annealed 0.1C-5Mn steel with the starting ultrafine lamellar duplex structure of ferrite and retained austenite during tempering within the range from 200 to 500 °C were studied by X-ray diffraction (XRD), transmission electron microscopy (TEM) and tensile testing. The results showed that there was a slight decrease in the RA volume fraction with increasing tempering temperature up to 400 °C. This caused a slight increase in the ultimate tensile strength (UTS) and a slight decrease in the total elongation (TE); thus, the product of UTS to TE (UTS×TE) as high as 31 GPa • % was obtained and remained nearly unchanged. However, a portion of the RA began to decompose when tempered at 500 °C and thus caused a ∼35% decrease of the RA fraction and a ∼16% decrease of the value of UTS×TE. It is concluded that the ultrafine lamellar duplex structure is rather stable and the excellent combination of strength and ductility could be retained with tempering temperature up to 400 °C. Thus, thermal processes such as galvanization are feasible for the tested steel provided that their temperatures are not higher than 400 °C.

      PubDate: 2017-09-01T02:10:30Z
      DOI: 10.1016/s1006-706x(17)30123-1
  • Cementites decomposition of a pearlitic ductile cast iron during
           graphitization annealing heat treatment
    • Authors: Min-qiang Gao; Ying-dong Qu; Guang-long Li; Jun-hua You; Rong-de Li
      Pages: 838 - 843
      Abstract: Publication date: August 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 8
      Author(s): Min-qiang Gao, Ying-dong Qu, Guang-long Li, Jun-hua You, Rong-de Li
      Cementites decomposition of a pearlitic ductile cast iron during graphitization annealing heat treatment was investigated. Fractographies and microstructures of heat treated samples were observed using a scanning electron microscope and mechanical properties were measured by a universal tensile test machine. The results indicated that during isothermal annealing at 750 °C, the tensile strength of pearlitic ductile cast iron was increased to a peak value at 0.5 h, and decreased gradually thereafter but the elongation was enhanced with the increase of annealing time. Moreover, the diffusion coefficient of carbon atoms could be approximately calculated as 0.56 µm2/s that could be regarded as the shortrange diffusion. As the holding time was short (0. 5 h), diffusion of carbon atoms was incomplete and mainly occurred around the graphites where the morphology of cementites changed from fragmentized shape to granular shape. In addition, the ductile cast iron with tensile strength of 740 MPa and elongation of 7% could be achieved after graphitization annealing heat treatment for 0. 5 h. Two principal factors should be taken into account. First, the decomposition of a small amount of cementites was beneficial for increasing the ductility up to elongation of 7%. Second, the diffusion of carbon atoms from cementites to graphites could improve the binding force between graphites and matrix, enhancing the tensile strength to 740 MPa.

      PubDate: 2017-09-01T02:10:30Z
      DOI: 10.1016/s1006-706x(17)30124-3
  • Evolution of microstructure, mechanical and magnetic properties of
           electrodeposited 50% Ni-Fe alloy foil after thermal treatment
    • Authors: Hong-ru Ren; Jin-tao Gao; Zhe Wang; Chong Li; Fu-qiang Wang; Zhan-cheng Guo
      Pages: 844 - 851
      Abstract: Publication date: August 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 8
      Author(s): Hong-ru Ren, Jin-tao Gao, Zhe Wang, Chong Li, Fu-qiang Wang, Zhan-cheng Guo
      In order to expand the application of the electrodeposited Ni-Fe alloy foil, their mechanical and magnetic properties were studied after heat treatment. The development of grain growth during annealing was in-situ online investigated using a heating stage microscope, and the texture was analyzed via X-ray diffraction (XRD) and electron back-scattered diffraction (EBSD). The results indicated that abnormal grain growth usually occurred during annealing at 1000–1050 °C. The {111} oriented grains preferentially grew as the annealing temperature and holding time increased. The plasticities of the electrodeposited Ni-Fe alloy foils after heat treatment were better than those of the original samples. The excellent ductility was obtained without a loss in magnetic properties after annealing at 1100 °C for 6 h.

      PubDate: 2017-09-01T02:10:30Z
      DOI: 10.1016/s1006-706x(17)30125-5
  • Lower limit law of welding windows for explosive welding of dissimilar
    • Authors: Chang-gen Shi; Xuan Yang; Yu-heng Ge; Jun You; Hong-bao Hou
      Pages: 852 - 857
      Abstract: Publication date: August 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 8
      Author(s): Chang-gen Shi, Xuan Yang, Yu-heng Ge, Jun You, Hong-bao Hou
      The influence of explosive charge thickness on the quality of explosive welding of dissimilar metals was investigated. The lower limit law should be followed in the course of explosive welding. Three welding experiments of stainless steel (410S) and steel (Q345R) were carried out in three different kinds of explosive charge thicknesses, namely 15, 25 and 35 mm. Interfaces of morphology and mechanical properties of three samples were observed and tested. It was found that micro and small wavy bonding is mainly formed for charge thickness of 15 mm whose strength is the highest with minor deformation and few defects in the interface; small and middle wavy bonding are mainly formed for charge thickness of 25 mm whose strength is comparatively mediocre; big wavy bonding is mainly formed for charge thickness of 35 mm whose strength is the lowest. The cause of high bonding strength of the micro and small wavy interface was analyzed and verified on the basis of the results of Electron Probe Micro-Analyzer (EPMA) tests of three selected samples.

      PubDate: 2017-09-01T02:10:30Z
      DOI: 10.1016/s1006-706x(17)30126-7
  • Temperature dependence of Lüders strain and its correlation with
           martensitic transformation in a medium Mn transformation-induced
           plasticity steel
    • Authors: Xiao-gang Wang; Ming-xin Huang
      Pages: 1073 - 1077
      Abstract: Publication date: November 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 11
      Author(s): Xiao-gang Wang, Ming-xin Huang
      The Lüders deformation behavior in a medium Mn transformation-induced plasticity (TRIP) steel is investigated at different temperatures ranging from 25 to 300 °C. It demonstrates that the Lüders band appears at all testing temperatures but with varied Lüders strains which do not change monotonically with temperature. The martensitic transformation is simultaneously observed within the Lüders band in varying degrees depending on the testing temperature. It is well verified that the martensitic transformation is not responsible for the formation of Lüders band, and a reasonable explanation is given for the non-monotonic variation of Lüders strain with increasing temperature.

      PubDate: 2017-11-16T06:22:13Z
      DOI: 10.1016/s1006-706x(17)30156-5
  • A thermodynamic model on predicting density of medium-Mn steels with
           experimental verification
    • Authors: Guo-hui Shen; Peng-yu Wen; Hai-wen Luo
      Pages: 1078 - 1084
      Abstract: Publication date: November 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 11
      Author(s): Guo-hui Shen, Peng-yu Wen, Hai-wen Luo
      A new model on predicting the density of hot-rolled multi-phased medium-Mn steel has been presented on the basis of thermodynamic calculations. This is an integrated model, which includes one for calculating the retained austenite (RA) fraction and the other for volume expansion during the austenite-to-martensite transformation, because both of them are key parameters for calculating the density of steel at ambient temperature. The existing empirical equations for calculating Mms temperature and lattice constants of both martensite and austenite have been all reassessed by the XRD measurements on the microstructures of seven hot-rolled medium-Mn steels. Finally, the densities of seven steels were calculated merely from compositions and compared with the measured ones. The difference between them is no more than 1%, suggesting that the presented model should be of good value in designing the low-density steels.

      PubDate: 2017-11-16T06:22:13Z
      DOI: 10.1016/s1006-706x(17)30157-7
  • Mechanical properties of a microalloyed bainitic steel after hot forging
           and tempering
    • Authors: Zhi-bao Xu; Wei-jun Hui; Zhan-hua Wang; Yong-jian Zhang; Xiao-ii Zhao; Xiu-ming Zhao
      Pages: 1085 - 1094
      Abstract: Publication date: November 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 11
      Author(s): Zhi-bao Xu, Wei-jun Hui, Zhan-hua Wang, Yong-jian Zhang, Xiao-ii Zhao, Xiu-ming Zhao
      Mechanical properties of a newly developed microalloyed bainitic steel were investigated after the hot forging, air cooling and tempering process. The microstructure of the as-forged bainitic steel mainly consists of granular bainite and ∼20 vol. % martensite. The fraction of retained austenite remains unchanged until tempering at 200 °C, above which it decreases significantly. The increase of tempering temperature leads to decreases of both ultimate tensile strength and total elongation but decreases of both yield strength and reduction of area. The maximum and minimum values of impact toughness were observed after tempering at around 200 and 400 °C, respectively. These effects are mainly attributed to the decomposition of martensite/austenite constituents and the tempering effects in martensite. The tempering of the forged bainitic steel at around 200 °C results in an excellent combination of strength and toughness, which is comparable to that of the conventional quenched-and-tempered 40Cr steel. Therefore, low-tempering treatment coupled with post-forging residual stress relieving is a feasible method to further improve the mechanical properties of the bainitic forging steel.

      PubDate: 2017-11-16T06:22:13Z
      DOI: 10.1016/s1006-706x(17)30158-9
  • Correlation of isothermal bainite transformation and austenite stability
           in quenching and partitioning steels
    • Authors: Shan Chen; Guang-zhen Wang; Chun Liu; Chen-chong Wang; Xian-ming Zhao; Wei Xu
      Pages: 1095 - 1103
      Abstract: Publication date: November 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 11
      Author(s): Shan Chen, Guang-zhen Wang, Chun Liu, Chen-chong Wang, Xian-ming Zhao, Wei Xu
      The possible decomposition of metastable austenite during the partitioning process in the high-end quenching and partitioning (Q&P) steels is somewhat neglected by most researchers. The effects of primary martensite and alloying elements including manganese, cobalt and aluminum on the isothermal decomposition of austenite during typical Q&P process were studied by dilatometry. The transformation kinetics was studied systematically and resulting microstructures were discussed in details. The results suggested that the primary martensite decreased the incubation period of isothermal decomposition by accelerating the nucleation process owing to dislocations especially on phase and grain boundaries. This effect can be eliminated by a flash heating which recovered dislocations. Co addition significantly promoted the bainite transformation during partitioning while Al and Mn suppressed the isothermal bainite transformation. The bainite transformation played an important role in carbon distribution during partitioning, and hence the amount and stability of austenite upon final quenching. The bainite transformation during partitioning is an important factor in optimizing the microstructure in Q&P steels.

      PubDate: 2017-11-16T06:22:13Z
      DOI: 10.1016/s1006-706x(17)30159-0
  • Tensile behavior and deformation mechanism of quenching and partitioning
           treated steels at different deforming temperatures
    • Authors: Lian-bo Luo; Wei Li; Yu Gong; Li Wang; Xue-jun Jin
      Pages: 1104 - 1108
      Abstract: Publication date: November 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 11
      Author(s): Lian-bo Luo, Wei Li, Yu Gong, Li Wang, Xue-jun Jin
      The effects of deforming temperatures on the tensile behaviors of quenching and partitioning treated steels were investigated. It was found that the ultimate tensile strength of the steel decreased with the increasing temperature from 25 to 100 °C, reached the maximum value at 300 °C, and then declined by a significant extent when the temperature further reached 400 °C. The total elongations at 100, 200 and 300 °C are at about the same level. The steel achieved optimal mechanical properties at 300 °C due to the proper transformation behavior of retained austenite since the stability of retained austenite is largely dependent on the deforming temperature. When tested at 100 and 200 °C, the retained austenite was reluctant to transform, while at the other temperatures, about 10 vol. % of retained austenite transformed during the tensile tests. The relationship between the stability of retained austenite and the work hardening behavior of quenching and partitioning treated steels at different deforming temperatures was also studied and discussed in detail. In order to obtain excellent mechanical properties, the stability of retained austenite should be carefully controlled so that the effect of transformation-induced plasticity could take place continuously during plastic deformation.

      PubDate: 2017-11-16T06:22:13Z
      DOI: 10.1016/s1006-706x(17)30160-7
  • In-situ microstructural evolutions of 5Mn steel at elevated temperature in
           a transmission electron microscope
    • Authors: Han-bo Jiang; Xi-nan Luo; Xiao-yan Zhong; Hui-hua Zhou; Cun-yu Wang; Jie Shi; Han Dong
      Pages: 1109 - 1114
      Abstract: Publication date: November 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 11
      Author(s): Han-bo Jiang, Xi-nan Luo, Xiao-yan Zhong, Hui-hua Zhou, Cun-yu Wang, Jie Shi, Han Dong
      The microstructural evolutions of 5Mn steel during various heat treatments have been investigated by in-situ transmission electron microscopy (TEM). The specimen of 5Mn steel was prepared using focused ion beam (FIB) milling, which allowed the selection of specific morphology of interest prior to the in-situ observation. The complete austenization at 800 °C was verified at the atomic scale by minimizing thermal expansion and sample drift in a heating holder based on micro-electro-mechanical-systems. During annealing at 650 °C, the formation of reverted austenite was dynamically observed, while the morphologies of austenite laths of 5Mn steel after in-situ heating were quite similar to that after ex-situ intercritical annealing. During annealing at 500 °C, the morphological evolution of cementite and associated Mn diffusion were investigated. It was demonstrated that a combination of FIB sampling and high temperature in-situ TEM enables us to probe the morphological evolution and elemental diffusion of specific areas of interest in steel at high spatial resolution.

      PubDate: 2017-11-16T06:22:13Z
      DOI: 10.1016/s1006-706x(17)30161-9
  • Microstructure evolution and mechanical properties influenced by
           austenitizing temperature in aluminum-alloyed TRIP-aided steel
    • Authors: Ju-hua Liang; Zheng-zhi Zhao; Cai-hua Zhang; Di Tang; Shu-feng Yang; Wei-ning Liu
      Pages: 1115 - 1124
      Abstract: Publication date: November 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 11
      Author(s): Ju-hua Liang, Zheng-zhi Zhao, Cai-hua Zhang, Di Tang, Shu-feng Yang, Wei-ning Liu
      The Fe-0. 21C-2. 2Mn-0. 49Si-1. 77 A1 transformation induced plasticity (TRIP)-aided steel was heat treated at various austenitizing temperatures under both TRIP-aided polygonal ferrite type (TPF) and annealed martensite matrix (TAM) processes. The microstructure evolution and their effects on mechanical properties were systematically investigated through the microstructure observation and dilatometric analysis. The microstructure homogeneity is improved in TPF steel heated at a high temperature due to the reduced banded martensite and the increased bainite. Compared with the mechanical properties of the TPF steels, the yield strength and elongation of the TAM steels are much higher, while the tensile strength is lower than that of TPF steels. The stability of intercritical austenite is affected by the heating temperature, and thus the following phase transformation influences the mechanical properties, such as the bainite transformation and the precipitation of polygonal ferrite. Obvious dynamic bainite transformation occurs at TAM850, TAM900 and TAM950. More proportion of polygonal ferrite is found in the sample heated at 950 °C. The bainite transformation beginning at a higher temperature results in the wider bainitic ferrite laths. The more proportion of polygonal ferrite and wide bainitic ferrite laths commonly contribute to the lower strength and better elongation. The uniform microstructure with lath-like morphology and retained austenite with high average carbon content ensures a good mechanical property in TAM850 with the product of strength and elongation of about 28 GPa · %.

      PubDate: 2017-11-16T06:22:13Z
      DOI: 10.1016/s1006-706x(17)30162-0
  • Effects of strain states on stability of retained austenite in medium Mn
    • Authors: Mei Xu; Yong-gang Yang; Jia-yong Chen; Di Tang; Hai-tao Jiang; Zhen-li Mi
      Pages: 1125 - 1130
      Abstract: Publication date: November 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 11
      Author(s): Mei Xu, Yong-gang Yang, Jia-yong Chen, Di Tang, Hai-tao Jiang, Zhen-li Mi
      Based on uniaxial tensile and plane strain deformation tests, the effects of strain states on the stability of RA (retained austenite) in medium Mn steels, which were subjected to IA (intercritical annealing) and Q&P (quenching and partitioning) processing, were investigated. The volume fractions of RA before and after deformation were measured at different equivalent strains. The transformation behaviors of RA were also investigated. The stability of RA differed across two different transformation stages at the plane strain state: the stability was much lower in the first stage than in the second stage. For the uniaxial tension strain state, the stability of RA corresponded only to a single transformation stage. The main reason was that there were two types of transformations from RA in the medium Mn steel for the plane strain state. One type was that the martensite originated in the strain-induced stacking faults (SISF). The other type was the strain-induced directly twin martensite at a certain equivalent strain. However, for the uniaxial tension state, only the strain-induced twin martensite was observed. Dislocation lines and dislocation tangles were also observed in specimens deformed at different strain states. In addition, complex microstructures of stacking faults and lath-like phases were observed within a grain at the plane strain state.

      PubDate: 2017-11-16T06:22:13Z
      DOI: 10.1016/s1006-706x(17)30163-2
  • Estimation of maximum inclusion by statistics of extreme values method in
           bearing steel
    • Authors: Chao Tian; Jian-hui Liu; Heng-chang Lu; Han Dong
      Pages: 1131 - 1136
      Abstract: Publication date: November 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 11
      Author(s): Chao Tian, Jian-hui Liu, Heng-chang Lu, Han Dong
      A statistic method, statistics of extreme values (SEV), was described in detail, which can estimate the size of maximum inclusion in steel. The characteristic size of the maximum inclusion in a high clean bearing steel (GCr15) was evaluated by this method, and the morphology and composition of large inclusions found were analyzed by scanning electron microscopy (SEM). When standard inspection area (S 0) is 280 mm2 the characteristic size of the biggest inclusion found in 30 standard inspection area is 23.93 µm, and it has a 99.9% probability of the characteristic size of maximum inclusion predicted being no larger than 36.85 pm in the experimental steel. SEM result shows that large inclusions found are mainly composed of CaS, calcium-aluminate and MgO. Compositing widely exists in large inclusions in high clean bearing steel. Compared with traditional evaluation method, SEV method mainly focuses on inclusion size, and the estimation result is not affected by inclusion types. SEV method is suitable for the inclusion evaluation of high clean bearing steel.

      PubDate: 2017-11-16T06:22:13Z
      DOI: 10.1016/s1006-706x(17)30164-4
  • Microstructure and mechanical properties of 20Si2CrNi3MoV steel treated by
           HDQP process
    • Authors: Chuan-feng Meng; Lei Zhang; Cun-yu Wang; Yu-jie Zhang; Ying-hui Wei; Yi-de Wang; Wen-quan Cao
      Pages: 1137 - 1142
      Abstract: Publication date: November 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 11
      Author(s): Chuan-feng Meng, Lei Zhang, Cun-yu Wang, Yu-jie Zhang, Ying-hui Wei, Yi-de Wang, Wen-quan Cao
      A combined process of hot-deformation plus two-step quenching and partitioning (HDQP) treatment was applied to a low-carbon 20Si2CrNi3MoV steel, and transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), Vickers hardness and tension test were used to characterize the microstructure and mechanical properties. More stable retained austenite due to fine microstructures and typical curved micromorphology is obtained, and the newly-treated steel obtains more retained austenite because of the effect of hot deformation. The retained austenite fraction increases and then decreases with the increasing quenching temperature from 200 to 350 °C. The maximum retained austenite fraction (18. 3%) and elongation (15%) are obtained to enhance the ductility.

      PubDate: 2017-11-16T06:22:13Z
      DOI: 10.1016/s1006-706x(17)30165-6
  • Effect of methane-hydrogen mixtures on flow and combustion of coherent
    • Authors: Ting Cheng; Kong Zhu; Kai Dong
      Pages: 1143 - 1151
      Abstract: Publication date: November 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 11
      Author(s): Ting Cheng, Kong Zhu, Kai Dong
      Coherent jets are widely used in electric arc furnace (EAF) steelmaking to increase the oxygen utilization and chemical reaction rates. However, the influence of fuel gas combustion on jet behavior is not fully understood yet. The flow and combustion characteristics of a coherent jet were thus investigated at steelmaking temperature using Fluent software, and a detailed chemical kinetic reaction mechanism was used in the combustion reaction model. The axial velocity and total temperature of the supersonic jet were measured via hot state experiments. The simulation results were compared with the experimental data and the empirical jet model proposed by Ito and Muchi and good consistency was obtained. The research results indicated that the potential core length of the coherent jet can be prolonged by optimizing the combustion effect of the fuel gas. Besides, the behavior of the supersonic jet in the subsonic section was also investigated, as it is an important factor for controlling the position of the oxygen lance. The investigation indicated that the attenuation of the coherent jet is more notable than that of the conventional jet in the subsonic section.

      PubDate: 2017-11-16T06:22:13Z
      DOI: 10.1016/s1006-706x(17)30166-8
  • Structural behavior of F− in mould flux melt of CaO-SiO2-Al2 O3-Na2
           O-CaF2 system
    • Authors: Qiang Gao; Yi Min; Cheng-jun Liu; Mao-fa Jiang
      Pages: 1152 - 1158
      Abstract: Publication date: November 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 11
      Author(s): Qiang Gao, Yi Min, Cheng-jun Liu, Mao-fa Jiang
      The influence of fluorine on the structure of CaO-SiO2-Al2O3-Na2O-CaF2 continuous-casting-type slag was measured by Raman spectroscopy, and the degree of polymerization of mould flux and the structural behavior of F− in the melt were investigated by classifying and quantifying the structural species of F− ions. The results exhibit that the main structural units of Si-O tetrahedra are Q0, Q1 and Q2 and the actual measured number of non-bridging oxygen ions in the [SiO4]-tetrahedra (denoted by NBO/T) increases from 2. 73 to 3. 44 with increasing the molar ratio of F to (F+O) (denoted by X F/X (F+O)) from 0. 06 to 0. 19. It means that the degree of polymerization of melt structure decreases with an increase in X F/X (F+O). In addition, most of F− ions were distributed in Si-O tetrahedra and Al-O tetrahedra. With increasing X F/X (F+O), the complex structural units Al-O tetrahedra are gradually replaced by discrete structural units AlF1– because of the breakage of Al-O bonds in Al-O tetrahedra by F− ions, and the Si-O (bridging oxygen) bonds of Si-O tetrahedra are broken to form [SiO n F1–n ]-tetrahedra by F− ions coordinating with Si4+.

      PubDate: 2017-11-16T06:22:13Z
      DOI: 10.1016/s1006-706x(17)30167-x
  • Thermo-elasto-visco-plastic finite element analysis on formation and
           propagation of of-corner subsurface cracks in bloom continuous casting
    • Authors: Yu-jun Li; Huan Li; Peng Lan; Hai-yan Tang; Jia-quan Zhang
      Pages: 1159 - 1168
      Abstract: Publication date: November 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 11
      Author(s): Yu-jun Li, Huan Li, Peng Lan, Hai-yan Tang, Jia-quan Zhang
      The formation and propagation of the popular off-corner subsurface cracks in bloom continuous casting were investigated through thermo-mechanical analysis using three coupled thermo-mechanical models. A two-dimensional thermo-elasto-visco-plastic finite element model was developed to predict the mould gap evolution, temperature profiles and deformation behavior of the solidified shell in the mould region. Then, a three-dimensional model was adopted to calculate the shell growth, temperature history and the development of stresses and strains of the shell in the following secondary cooling zones. Finally, another three-dimensional model was used to analyze the stress distributions in the straightening region. The results showed that the off-corner cracks in the shell originated from the mould owing to the tensile strain developed in the crack sensitive regions of the solidification front, and they could be driven deeper by the possible severe surface temperature rebound and the extensive tensile stress in the secondary cooling zone, especially upon the straightening operation of the bloom casting. It is revealed that more homogenous shell temperature and thickness can be obtained through optimization of mould corner radius, casting speed and secondary cooling scheme, which help to decrease stress and strain concentration and therefore prevent the initiation of the cracks.

      PubDate: 2017-11-16T06:22:13Z
      DOI: 10.1016/s1006-706x(17)30168-1
  • Sintering flue gas desulfurization with different carbon materials
           modified by microwave irradiation
    • Authors: Shan Ren; Fu-qiang Guo Zhao Jie Yang Yao Ming Kong
      Abstract: Publication date: October 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 10
      Author(s): Shan Ren, Fu-qiang Guo, Qi Zhao, Jie Yang, Lu Yao, Ming Kong
      Modification of metallurgical coke, biomass char and semi-coke was carried out using a microwave device with power of 450–850 W and irradiation time of 6–12 min. The desulfurization rates of three carbon materials before and after modification were tested. The effects of microwave power and irradiation time on the pore texture and surface chemical characteristics of the three carbon materials were examined by SEM, BET and Fourier transform infrared spectroscopy (FTIR). The results showed that the specific surface area, total pore volume and pore diameter of biomass char and semi-coke after irradiation decreased slightly. Noteworthily, the pore diameter turned small and the acidic functional groups on their surface decomposed, thereby the basicity of carbon surface increased by microwave modification. The optimal promotion of desulfurization rate of three carbon materials was semi-coke irradiated at 850 W for 9 min and the sulfur dioxide adsorption rate was up to 45%.

      PubDate: 2017-10-10T22:52:14Z
  • Non-isothermal study of gasification process of coal char and biomass char
           in CO2 condition
    • Authors: Tao Guang-wei; Wang Jian-liang Zhang Teng-fei Song Run-sheng
      Abstract: Publication date: October 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 10
      Author(s): Tao Xu, Guang-wei Wang, Jian-liang Zhang, Teng-fei Song, Run-sheng Xu
      Non-isothermal method was used to study gasification characteristics of three coal chars and one biomass char. Four chars were made from anthracite coal (A), bituminous coal (B), lignite coal (L), and wood refuse (W), respectively. The gasification process was studied by random pore model (RPM), unreacted core model (URCM) and volumetric model (VM). With an increase in metamorphic grade, the gasification reactivity of coal char decreased, and the gasification reactivity of biomass char was close to that of low metamorphic coal char. With an increase in heating rate, the gasification of all samples moved towards high temperature zone, and the whole gasification time decreased. It was concluded from kinetics analysis that the above-mentioned three models could be used to describe the gasification process of coal char, and the RPM fitted the best among the three models. In the RPM, the activation energies of gasification were 193. 9, 225. 3 and 202. 8 kJ/mol for anthracite coal char, bituminous coal char and lignite coal char, respectively. The gasification process of biomass char could be described by the URCM and VM, while the URCM performed better. The activation energy of gasification of wood refuse char calculated by the URCM was 282. 0 kJ/mol.

      PubDate: 2017-10-10T22:52:14Z
  • Recovery of iron and copper from copper tailings by coal-based direct
           reduction and magnetic separation
    • Authors: Chao Ceng; Hua-jun Wang Wen-tao Cheng-shuai Shi
      Abstract: Publication date: October 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 10
      Author(s): Chao Ceng, Hua-jun Wang, Wen-tao Hu, Li Li, Cheng-shuai Shi
      A technique comprising coal-based direct reduction followed by magnetic separation was presented to recover iron and copper from copper slag flotation tailings. Optimal process parameters, such as reductant and additive ratios, reduction temperature, and reduction time, were experimentally determined and found to be as follows: a limestone ratio of 25%, a bitumite ratio of 30%, and reduction roasting at 1473 K for 90 min. Under these conditions, copper-bearing iron powders (CIP) with an iron content of 90.11% and copper content of 0.86%, indicating iron and copper recoveries of 87.25% and 83.44% respectively, were effectively obtained. Scanning electron microscopy and energy dispersive spectroscopy of the CIP revealed that some tiny copper particles were embedded in metal iron and some copper formed alloy with iron, which was difficult to achieve the separation of these two metals. Thus, the copper went into magnetic products by magnetic separation. Adding copper into the steel can produce weathering steel. Therefore, the CIP can be used as an inexpensive raw material for weathering steel.

      PubDate: 2017-10-10T22:52:14Z
  • Three-dimensional structure and micro-mechanical properties of iron ore
    • Authors: Wei Wang; Ming Deng Run-sheng Wei-bo Ze-lin Ouyang Xiao-bo Huang
      Abstract: Publication date: October 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 10
      Author(s): Wei Wang, Ming Deng, Run-sheng Xu, Wei-bo Xu, Ze-lin Ouyang, Xiao-bo Huang, Zheng-liang Xue
      A new analysis method based on serial sectioning and three-dimensional (3D) reconstruction was developed to characterize the mineral microstructure of iron ore sinter. Through the 3D reconstruction of two types of iron ore sinters, the morphology and distribution of minerals in three-dimensional space were analyzed, and the volume fraction of minerals in a 3D image was calculated based on their pixel points. In addition, the microhardness of minerals was measured with a Vickers hardness tester. Notably, different mineral compositions and distributions are obtained in these two sinters. The calcium ferrite in Sinter 1 is dendritic with many interconnected pores, and these grains are crisscrossed and interwoven; the calcium ferrite in Sinter 2 is strip shaped and interweaves with magnetite, silicate and columnar pores. The calculated mineral contents based on a two-dimensional region are clearly different among various layers. Quantitative analysis shows that Sinter 1 contains a greater amount of calcium ferrite and hematite, whereas Sinter 2 contains more magnetite and silicate. The microhardness of minerals from highest to lowest is hematite, calcium ferrite, magnetite and silicate. Thus, Sinter 1 has a greater tumbler strength than Sinter 2.

      PubDate: 2017-10-10T22:52:14Z
  • Comparison of sintering performance of typical specular hematite ores with
           distinct size distributions
    • Authors: Cong-cong Yang; De-qing Zhu Ben-jing Shi Jian Pan Li-ming Xiao-bo
      Abstract: Publication date: October 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 10
      Author(s): Cong-cong Yang, De-qing Zhu, Ben-jing Shi, Jian Pan, Li-ming Lu, Xiao-bo Li, Ya-ping Mo
      The sintering performance of three typical specular hematite ores (coarse SO-A, intermediate SO-B and ultrafine SO-C) was compared in an industrial ore blend through pilot-scale sinter pot tests. The effect of particle size of specular hematite ores on their granulation and sintering performance was revealed. Compared with the coarse SO-A fine and ultrafine SO-C concentrate, the intermediate SO-B showed inferior granulation and sintering performance characterized with poorer bed permeability and productivity, lower sinter strength and higher fuel rates. A new material preparation method was hence proposed and verified at both pilot and industrial scales. The proposed method by mixing SO-B with a high amount of goethite-type iron ore fines was found to be an effective way in improving the granulation and assimilative characteristics of ore blend comprising 31% intermediate SO-B, leading to improved sinter productivity and lowered fuel rates. The metallurgical properties and microstructure of sinters were also investigated. The sinters obtained through the proposed preparation method were generally stronger and more reducible on account of better sinter structure with more relict hematite ultimately connected with needle-like silico-ferrite of calcium and aluminum and lower porosity.

      PubDate: 2017-10-10T22:52:14Z
  • Corrosion mechanism research and microstructure analysis of Baosteel No. 3
           blast furnace hearth
    • Authors: Xun-fu Wang; Qi-jie Zhai
      Abstract: Publication date: October 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 10
      Author(s): Xun-fu Wang, Qi-jie Zhai
      Baosteel No. 3 blast furnace hearth was divided into tuyere area, taphole area, taphole upper side wall and taphole lower side wall according to different working situations. Through chemical composition analysis, scanning electron microscopy, X-ray diffraction, energy dispersive spectrometry and other means, chemical composition and microstructure of different parts of hearth carbon brick were analyzed and markedly different corrosion mechanisms of these areas were found. Zn element in form of ZnO mainly deposited on the hot side of carbon brick. There was no obvious evidence that Zn permeates into carbon bricks and erodes them. Except for taphole area, K, Na, and Fe contents from hot side to cold side gradually rise and fall, resulting in the decrease of apparent porosity, the increase of density and the higher thermal conductivity compared with those of new carbon brick. The higher content of Fe in carbon brick leads to more serious erosion because Fe has greatly changed the physical properties of carbon brick. In the taphole area, the contents of Si and Al present obvious concentration gradient because of the mechanical souring of molten iron and slag. The SiO2 and Al2O3 particles that have different expansion factors with carbon brick damaged the carbon substrate because of temperature fluctuation. The graphitized carbon found on H4 where is the most serious corrosion site means that the carbon brick ever directly contacts with molten iron.

      PubDate: 2017-10-10T22:52:14Z
  • Interfacial microstructure and mechanical properties of diffusion-bonded
           joints of titanium TC4 (Ti-6Al-4V) and Kovar (Fe-29Ni-17Co) alloys
    • Authors: Ting-feng Song; Xiao-song Jiang Zhen-yi Shao De-feng De-gui Zhu Min-hao
      Abstract: Publication date: October 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 10
      Author(s): Ting-feng Song, Xiao-song Jiang, Zhen-yi Shao, De-feng Mo, De-gui Zhu, Min-hao Zhu, Christina H. Young, Zhi-ping Luo
      Diffusion bonding is a near net shape forming process that can join dissimilar materials through atomic diffusion under a high pressure at a high temperature. Titanium alloy TC4 (Ti-6Al-4V) and 4J29 Kovar alloy (Fe-29Ni-17Co) were diffusely bonded by a vacuum hot-press sintering process in the temperature range of 700–850 °C and bonding time of 120 min, under a pressure of 34. 66 MPa. Interfacial microstructures and intermetallic compounds of the diffusion-bonded joints were characterized by optical microscopy, scanning electron microscopy, X-ray diffraction (XRD) and energy dispersive spectroscopy (EDS). The elemental diffusion across the interface was revealed by electron probe microanalysis. Mechanical properties of joints were investigated by micro Vickers hardness and tensile strength. Results of EDS and XRD indicated that (Fe, Co, Ni)-Ti, TiNi, Ti2Ni, TiNi2, Fe2Ti, Ti17Mn3 and Al6 Ti19 were formed at the interface. When the bonding temperature was raised from 700 to 850 °C, the voids of interface were reduced and intermetallic layers were widened. Maximum tensile strength of joints at 53. 5 MPa was recorded by the sintering process at 850 °C for 120 min. Fracture surface of the joint indicated brittle nature, and failure took place through interface of intermetallic compounds. Based on the mechanical properties and microstructure of the diffusion-bonded joints, diffusion mechanisms between Ti-6Al-4V titanium and Fe-29Ni-17Co Kovar alloys were analyzed in terms of elemental diffusion, nucleation and growth of grains, plastic deformation and formation of intermetallic compounds near the interface.

      PubDate: 2017-10-10T22:52:14Z
  • Effects of Al contents on microstructure and properties of hot-dip Zn-Al
    • Authors: Zhi-feng Yong-quan; Guang-ming Gao Jun-jian Tang Xiang-jun Zhang Zhen-yu Liu
      Abstract: Publication date: October 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 10
      Author(s): Zhi-feng Li, Yong-quan He, Guang-ming Gao, Jun-jian Tang, Xiang-jun Zhang, Zhen-yu Liu
      A new hot-dip galvanizing method was employed on hot-rolled low carbon steel. The effects of Al contents on microstructure, micro-hardness and corrosion resistance of Zn-Al alloy coatings were systematically investigated. Phase composition, microstructure and element distribution in Zn-Al alloy coatings were analyzed using X-ray diffraction (XRD) and electron probe micro analysis (EPMA), respectively. It is found that Al content (0. 6–6. 0 wt. %) in galvanizing zinc affects surface quality and adhesion between coatings and matrix in the newly developed method. In addition, with increasing Al content, micro-hardness significantly increased due to the increase in Zn-Al eutectoid phases. Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) also revealed that increase in Al plays a noticeable role in improving the corrosion resistance of Zn-Al alloy coatings.

      PubDate: 2017-10-10T22:52:14Z
  • Scaling laws and mechanical properties of nanoporous copper
    • Authors: Lin-kai Guo; Lei Wang Dong-hui Yang
      Abstract: Publication date: October 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 10
      Author(s): Lin-kai Guo, Lei Wang, Dong-hui Yang
      Through molecular dynamics simulations, the mechanical behavior of nanoporous copper under impact loading was investigated with relative densities ranging from 77.91% to 98.36%, focusing on deformation mechanism, the scaling laws and influence of ligament sizes. Results show that the classical Gibson-Ashby's scaling laws should be modified for prediction of both the Young's modulus and yield stress. A proportional relationship is established between cell wall thickness and yield stress, and new modified scaling equations are built for nanoporous copper with consideration on both relative mass density and size effects of ligaments. The size effect can be explained by larger surface area/volume ratio of samples with thinner ligament size and limited dislocation source activation due to narrow space between larger numbers of voids.

      PubDate: 2017-10-10T22:52:14Z
  • Microstructural evolution of Al-Si coating and its influence on high
           temperature tribological behavior of ultra-high strength steel against H13
    • Authors: Meng-xuan Guo; Kai-xiang Gao Wu-rong Wang Xi-cheng Wei
      Abstract: Publication date: October 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 10
      Author(s): Meng-xuan Guo, Kai-xiang Gao, Wu-rong Wang, Xi-cheng Wei
      Al-Si coated ultra-high strength steel (UHSS) has been commonly applied in hot stamping process. The influence of austenitizing temperature on microstructure of Al-Si coating of UHSS during hot stamping process and its tribological behavior against H13 steel under elevated temperature were simulatively investigated. The austenitizing temperature of Al-Si coated UHSS and its microstructual evolution were confirmed and analyzed by differential scanning calorimetry and scanning electron microscopy. A novel approach to tribological testing by replicating hot stamping process temperature history was presented. Results show that the hard and stable phases Fe2Al5 + FeAl2 formed on Al-Si coating surface after exposure to 930 °C for 5 min, which was found to be correlated to the tribological behavior of coating. The friction coefficient of coated steel was more stable and higher than that of uncoated one. The main wear mechanism of Al-Si coated UHSS was adhesion wear, while abrasive wear was dominant for the uncoated UHSS.

      PubDate: 2017-10-10T22:52:14Z
  • Effect of cellular recrystallization on tensile properties of a
           nickel-based single crystal superalloy containing Re and Ru
    • Authors: Zhen-xue Shi; Shi-zhong Liu Xiao-dai Yue Li-jie Wan-peng Yang Xiao-guang
      Abstract: Publication date: October 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 10
      Author(s): Zhen-xue Shi, Shi-zhong Liu, Xiao-dai Yue, Li-jie Hu, Wan-peng Yang, Xiao-guang Wang, Jia-rong Li
      A nickel-based single crystal superalloy containing Re and Ru was cast in a directional solidification furnace. The single crystal specimens after standard heat treatment were grit blasted with different pressures and then heat treated at 1100 °C for 4 h under vacuum condition. The evolution of recrystallized microstructure and its effect on the tensile properties at 850 and 980 °C were investigated. After heat treatment, the cellular microstructure was observed, and the thickness of the cellular recrystallization zone increases with the increase in grit blasting pressure. The appearance of the cellular structure undermines the tensile properties. Both the tensile strength and elongation decrease with increasing the thickness of the cellular structure. The recrystallized grain boundaries can act as the channels for the crack initiation and propagation during tensile test. The low bearing capacity of recrystallized layers and the local stress concentration resulting from the notch effect of cracking were the main reasons for the decrease of tensile properties.

      PubDate: 2017-10-10T22:52:14Z
  • Erosion corrosion of low-alloy wear-resistant steels in alkaline slurry
    • Authors: Feng-ming Song; Lin-xiu
      Abstract: Publication date: October 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 10
      Author(s): Feng-ming Song, Lin-xiu Du
      Erosion corrosion causes significant problems in various industrial environments through a synergistic effect which results in much greater weight loss than the sum of the weight losses in the individual processes. The erosion-corrosion behavior of three low-alloy steels was investigated in a simulated concrete slurry using the rotation method. The key influencing factors and mechanism of material degradation were analyzed. The experimental results indicate that the weight loss increases with the linear velocity according to a nearly exponential relationship (W = KVn ), where n is 1. 40–2. 14. This weight loss is mainly caused by erosion in the alkaline slurry, and steels with higher tensile strengths show higher erosion-corrosion resistance. The formation of many platelets and ring cracks and their removal from the sample surface during erosion corrosion in the slurry are thought to constitute the mechanism responsible for this weight loss. These platelets and ring cracks are formed by solid particles striking the sample surface. Craters are initially produced and subsequently disappear as they grow and come in contact with each other. Fewer craters were observed on the surfaces of samples that exhibited higher weight loss. The surface of the material became work-hardened because of the effect of the particles striking and scratching, and a deformed layer was produced on the surface for steels of lower strengths, leading to deeper and more abundant gouges.

      PubDate: 2017-10-10T22:52:14Z
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