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  Subjects -> ENVIRONMENTAL STUDIES (Total: 770 journals)
    - ENVIRONMENTAL STUDIES (696 journals)
    - POLLUTION (23 journals)
    - TOXICOLOGY AND ENVIRONMENTAL SAFETY (40 journals)
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ENVIRONMENTAL STUDIES (696 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: 6)
Rivista di Studi sulla Sostenibilità     Full-text available via subscription  
Russian Journal of Ecology     Hybrid Journal   (Followers: 1)
S.A.P.I.EN.S     Open Access   (Followers: 2)
Safety Science     Hybrid Journal   (Followers: 30)
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: 11)
Science of The Total Environment     Hybrid Journal   (Followers: 25)
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: 11)
Studies in Environmental Science     Full-text available via subscription   (Followers: 5)
Sustainability     Open Access   (Followers: 20)
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: 6)
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: 11)
Theoretical Ecology Series     Full-text available via subscription   (Followers: 1)
Toxicologic Pathology     Hybrid Journal   (Followers: 20)
Toxicological & Environmental Chemistry     Hybrid Journal   (Followers: 4)
Toxicological Sciences     Hybrid Journal   (Followers: 12)
Toxicology     Hybrid Journal   (Followers: 18)
Toxicology and Applied Pharmacology     Hybrid Journal   (Followers: 19)
Toxicology and Industrial Health     Hybrid Journal   (Followers: 7)
Toxicology in Vitro     Hybrid Journal   (Followers: 11)
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: 25)
Transylvanian Review of Systematical and Ecological Research     Open Access  
Trends in Ecology & Evolution     Full-text available via subscription   (Followers: 216)
Trends in Environmental Analytical Chemistry     Hybrid Journal   (Followers: 2)
Trends in Pharmacological Sciences     Full-text available via subscription   (Followers: 26)
Tropicultura     Open Access  
UCLA Journal of Environmental Law and Policy     Open Access   (Followers: 4)
UD y la Geomática     Open Access  
Universidad y Ciencia     Open Access   (Followers: 1)
Urban Studies     Hybrid Journal   (Followers: 58)
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: 24)
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: 17)
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: 5)
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: 4)
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  [3044 journals]
  • Current status and development trends of innovative blast furnace
           ironmaking technologies aimed to environmental harmony and operation
           intellectualization
    • 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
           gasifier
    • 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
           metals
    • 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
       
  • Ripening behavior of M23C6 carbides in P92 steel during aging at 800
           °C
    • Authors: Xu Yang; Bo Liao; Fu-ren Xiao; Wei Yan; Yi-yin Shan; Ke Yang
      Pages: 858 - 864
      Abstract: Publication date: August 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 8
      Author(s): Xu Yang, Bo Liao, Fu-ren Xiao, Wei Yan, Yi-yin Shan, Ke Yang
      The rapid coarsening of the M23C6 carbides has been held responsible for the creep fracture in 9–12Cr martensitic heat resistant steels. A commercial P92 steel was subjected to thermal aging at a high temperature of 800 °C to investigate the ripening behavior of the M23C6 carbides. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were employed to characterize the microstructure evolution, especially the ripening process of the M23C6 carbides. The new concept of the effective mean size, dependent on the critical radius, was introduced to correct the measured mean size and then the Ostwald theory was applied to describe the ripening behavior of the M23C6 carbides. The ripening of the M23C6 carbides was revealed to be grain boundary diffusion controlled.

      PubDate: 2017-09-01T02:10:30Z
      DOI: 10.1016/s1006-706x(17)30127-9
       
  • Two-phase sink vortex suction mechanism and penetration dynamic
           characteristics in ladle teeming process
    • Authors: Da-peng Tan; Ye-sha Ni; Li-bin Zhang
      Pages: 669 - 677
      Abstract: Publication date: July 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 7
      Author(s): Da-peng Tan, Ye-sha Ni, Li-bin Zhang
      At the late stage of continuous casting (CC) ladle teeming, sink vortex can suck the liquid slag into tundish, and cause negative influences on the cleanliness of molten steel. To address this issue, a two-phase fluid mechanical modeling method for ladle teeming was proposed. Firstly, a dynamic model for vortex suction process was built, and the profiles of vortex flow field were acquired. Then, based on the level set method (LSM), a two-phase 3D interface coupling model for slag entrapment was built. Finally, in combination with high-order essentially non-oscillatory (ENO) and total variation diminishing (TVD) methods, a LSM-based numerical solution method was proposed to obtain the 3D coupling evolution regularities in vortex suction process. Numerical results show that the vortex with higher kinetic energy can form an expanded sandglass-shape region with larger slag fraction and lower rotating velocity; there is a pressure oscillation phenomenon at the vortex penetration state, which is caused by the energy shock of two-phase vortex penetration coupling.

      PubDate: 2017-07-21T06:44:29Z
      DOI: 10.1016/s1006-706x(17)30101-2
       
  • Oxidation kinetics of ilmenite concentrate by non-isothermal
           thermogravimetric analysis
    • Authors: Ying-yi Zhang; Wei Lv; Xue-wei Lv; Chen-guang Bai; Ke-xi Han; Bing Song
      Pages: 678 - 684
      Abstract: Publication date: July 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 7
      Author(s): Ying-yi Zhang, Wei Lv, Xue-wei Lv, Chen-guang Bai, Ke-xi Han, Bing Song
      The non-isothermal oxidation experiments of ilmenite concentrate were carried out at various heating rates under air atmosphere by thermogravimetry. The oxidation kinetic model function and kinetic parameters of apparent activation energy (E a) were evaluated by Málek and Starink methods. The results show that under air atmosphere, the oxidation process of ilmenite concentrate is composed of three stages, and the chemical reaction (G(α) = 1—(1—α)2, where α is the conversion degree) plays an important role in the whole oxidation process. At the first stage (α = 0. 05–0. 30), the oxidation process is controlled gradually by secondary chemical reaction with increasing conversion degree. At the second stage (α = 0.30–0.50), the oxidation process is completely controlled by the secondary chemical reaction (G(α) = 1 – (1 – α)2). At the third stage (α=0. 50 – 0.95), the secondary chemical reaction weakens gradually with increasing conversion degree, and the oxidation process is controlled gradually by a variety of functions; the kinetic equations are G(α)–(1–α)−1 (ß=10 K · min−1, where ß is heating rate), G(α) = (1 – α) −½ (ß= 15 – 20 K · min−1), and G(α) = (1 – α)−2(ß=25 K · min−1), respectively. For the whole oxidation process, the activation energies follow a parabolic law with increasing conversion degree, and the average activation energy is 160. 56 kJ · mol−1.

      PubDate: 2017-07-21T06:44:29Z
      DOI: 10.1016/s1006-706x(17)30102-4
       
  • Precipitation behavior of titanium nitride on a primary inclusion particle
           during solidification of bearing steel
    • Authors: Liang Yang; Bryan A. Webler; Guo-guang Cheng
      Pages: 685 - 690
      Abstract: Publication date: July 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 7
      Author(s): Liang Yang, Bryan A. Webler, Guo-guang Cheng
      Titanium nitride precipitation on a primary inclusion particle during solidification of bearing steel has been tracked by varying temperature in a confocal scanning violet laser microscope. Upon precipitation, an obvious growth of titanium nitride on a primary inclusion particle was observed due to the rapid solute diffusion in liquid steel. The onset of titanium nitride precipitation did not change with primary inclusion particle size, but the time of growth was greater for a smaller primary inclusion particle. Meanwhile, the particle size displayed little influence on the total precipitated amount of titanium nitride on it under the same conditions. At the later period of solidification, almost no change occurred in inclusion size, but the inclusion shape varied from circle to almost square in two-dimension, or cubic in three-dimension, to attain the equilibrium with steel.

      PubDate: 2017-07-21T06:44:29Z
      DOI: 10.1016/s1006-706x(17)30103-6
       
  • Niobium and phosphorus behavior during melting-separation process of
           pre-reduced niobium ore concentrate
    • Authors: Yu-bao Liu; Zhi-hong Zhang; Er-xiong Zhao; Xian-heng Zhang; Xiao-qing Wang; Guo-hua Chen
      Pages: 691 - 696
      Abstract: Publication date: July 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 7
      Author(s): Yu-bao Liu, Zhi-hong Zhang, Er-xiong Zhao, Xian-heng Zhang, Xiao-qing Wang, Guo-hua Chen
      The pre-reduced Bayan Obo ferroniobium (FeNb) ore concentrate block was taken as raw materials for studying the physical properties of niobium-enriched slag and changes in niobium recovery rate. In addition, the dephosphorization rate of the slag under different melting-separation conditions was investigated using the melting-separation test. The research results demonstrate that (i) the niobium recovery rate and dephosphorization rate of the slag decrease with the increase in melting-separation temperature; (ii) the niobium recovery rate of the slag initially increases and then decreases with increase in basicity and time; and (iii) the dephosphorization rate of the slag increases with the increase in basicity and time. When the test was performed under the conditions of basicity of 0. 6 – 0. 7, time of 7–10 min, and temperature of 1400–1450 °C, the niobium recovery rate and dephosphorization rate are over 96% and 95%, respectively. By scanning electron microscopy, it is observed that niobium mainly exists in the form of calcium and titanium silicate within the slag phase, with uneven distribution.

      PubDate: 2017-07-21T06:44:29Z
      DOI: 10.1016/s1006-706x(17)30104-8
       
  • Sintering of solid waste generated in iron and steel manufacturing process
           in Shougang Jingtang
    • Authors: Yuan-dong Pei; Sheng-li Wu; Shao-guo Chen; Zhi-xing Zhao; Gang An; Zheng-ming Cheng; Yao-sheng Luo
      Pages: 697 - 704
      Abstract: Publication date: July 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 7
      Author(s): Yuan-dong Pei, Sheng-li Wu, Shao-guo Chen, Zhi-xing Zhao, Gang An, Zheng-ming Cheng, Yao-sheng Luo
      It is important to make full use of waste generated in the iron and steel manufacturing process for energy saving, emission reduction, low carbon production and a circular economy. Based on research on different kinds of industrial solid wastes from Shougang Jingtang, wastes have been optimized for use in sintering. At first, basic tests for all kinds of solid wastes that may be used in sintering were carried out, including chemical composition, calorific value of a fuel, holding time at high temperatures, the sintering pot test, etc. The results show that the appropriate solid waste ratios for current sintering conditions are: steel slag <5%, scale 2.0%, environmental ash 2.0%, and cyclone ash 1.0%; blast furnace dry ash, sintering electric field ash, and steelmaking ash should not be circulated in sintering. As for the fuel structure, both coking ash and nut coke should be below 15%. By optimizing the addition of solid wastes, the damage of harmful elements to sintering and blast furnaces has been significantly reduced, which satisfies the demands for blast furnace materials and earns benefits. The utilization of solid wastes has made a contribution to the circular economy and sustainable development.

      PubDate: 2017-07-21T06:44:29Z
      DOI: 10.1016/s1006-706x(17)30105-x
       
  • Effects of tantalum on austenitic transformation kinetics of RAFM steel
    • Authors: Jian-guo Chen; Yong-chang Liu; Chen-xi Liu; Bi-yu Yan; Hui-jun Li
      Pages: 705 - 710
      Abstract: Publication date: July 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 7
      Author(s): Jian-guo Chen, Yong-chang Liu, Chen-xi Liu, Bi-yu Yan, Hui-jun Li
      The RAFM (reduced activation ferritic/martensitic) steels containing different tantalum contents (0 wt. %, 0. 027 wt. %, 0. 073 wt. %) were designed and cast. Differential scanning calorimetry and optical microscopy were employed to explore the influence of tantalum content on the austenitic transformation of RAFM steels. The austenitic transformation kinetics was described by a phase-transformation model. The model, involving site saturation nucleation, diffusion-controlled growth and impingement correction, was established based on the classical Johnson-Mehl-Avrami-Kolmogorov model. The phase-transformation kinetics parameters, including D 0 (pre-exponential factor for diffusion) and Q d (activation energy for diffusion), were calculated by fitting the experimental data and the kinetic model. The results indicated that the average grain size is decreased with the increase of tantalum. The values of A c1 and A c3 (onset and finish temperature of austenitic transformation, respectively) are increased by increasing the tantalum content. The increase of tantalum caused the decrease of D 0. However, Q d is increased with the increase of tantalum. In addition, as a carbides forming element, tantalum would reduce the carbon diffusion coefficient and slow down the austenitic transformation rate.

      PubDate: 2017-07-21T06:44:29Z
      DOI: 10.1016/s1006-706x(17)30106-1
       
  • Influence of cooling rate on magneto-structural transition and
           magnetocaloric effect of Ni30 Cu8 Co12 Mn37 Ga13 alloy
    • Authors: Zhu-jun Jiang; Yu-ye Wu; Jing-min Wang; Cheng-bao Jiang
      Pages: 711 - 717
      Abstract: Publication date: July 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 7
      Author(s): Zhu-jun Jiang, Yu-ye Wu, Jing-min Wang, Cheng-bao Jiang
      The influence of heat treatment with different cooling rates on phase transition behaviors and magnetocaloric effect is systematically studied. Difference in atomic order is induced by changing cooling rates, where ordered phase is obtained in the furnace cooled (FC) sample while disordered phase is reserved in the water quenched (WQ) sample. The coupled magneto-structural transition is detected in both samples but the characteristic temperature significantly shifts to lower temperatures with increasing atomic order. Giant magnetic entropy change (ΔSmag) derived from magnetic field induced martensitic transformation is confirmed for both samples, and can be remarkably enhanced by the atomic ordering. The largest ΔSmag of 20. 9 J/(kg · K) is obtained at 307. 5 K under 5 T in the FC sample.

      PubDate: 2017-07-21T06:44:29Z
      DOI: 10.1016/s1006-706x(17)30107-3
       
  • Microstructure characteristics of segregation zone in 17-4PH stainless
           steel piston rod
    • Authors: Jia-long Tian; Wei Wang; Wei Yan; Zhou-hua Jiang; Yi-yin Shan; Ke Yang
      Pages: 718 - 723
      Abstract: Publication date: July 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 7
      Author(s): Jia-long Tian, Wei Wang, Wei Yan, Zhou-hua Jiang, Yi-yin Shan, Ke Yang
      The segregation of Cu and Ni in a 17-4PH stainless steel piston rod has been confirmed to be responsible for the cracking after heat treatment. Further investigation showed that the segregation zone was composed of three layers, namely the fine grain martensitic layer, the coarse grain martensitic layer and the coarse grain austenitic layer from the matrix to the crack surface. Three button ingots with the same chemical compositions as those three layers have been prepared to evaluate the grain size distribution, microstructure and mechanical properties. The effects of Cu and Ni segregation on the microstructures of those three layers have been explored by thermodynamic calculation. Based on the microstructure and mechanical properties results, an intensive understanding of the cracking in the segregation zone was therefore reached.

      PubDate: 2017-07-21T06:44:29Z
      DOI: 10.1016/s1006-706x(17)30108-5
       
  • Dynamic mechanical behavior of ultra-high strength steel 30CrMnSiNi2 A at
           high strain rates and elevated temperatures
    • Authors: Qiu-lin Niu; Wei-wei Ming; Ming Chen; Si-wen Tang; Peng-nan Li
      Pages: 724 - 729
      Abstract: Publication date: July 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 7
      Author(s): Qiu-lin Niu, Wei-wei Ming, Ming Chen, Si-wen Tang, Peng-nan Li
      During high speed machining in the field of manufacture, chip formation is a severe plastic deformation process including large strain, high strain rate and high temperature. And the strain rate in high speed cutting process can be achieved to 105 s−1. 30CrMnSiNi2 A steel is a kind of important high-strength low-alloy structural steel with wide application range. Obtaining the dynamic mechanical properties of 30CrMnSiNi2 A under the conditions of high strain rate and high temperature is necessary to construct the constitutive relation model for high speed machining. The dynamic compressive mechanical properties of 30CrMnSiNi2 A steel were studied using split Hopkinson pressure bar (SHPB) tests at 30 – 700 °C and 3000 – 10000 s−1. The stress-strain curves of 30CrMnSiNi2 A steel at different temperatures and strain rates were investigated, and the strain hardening effect and temperature effect were discussed. Experimental results show that 30CrMnSiNi2 A has obvious temperature sensitivity at 300 °C. Moreover, the flow stress decreased significantly with the increase of temperature. The strain hardening effect of the material at high strain rate is not significant with the increase of strain. The strain rate hardening effect is obvious with increasing the temperature. According to the experimental results, the established Johnson-Cook (J-C) constitutive model of 30CrMnSiNi2 A steel could be used at high strain rate and high temperature.

      PubDate: 2017-07-21T06:44:29Z
      DOI: 10.1016/s1006-706x(17)30109-7
       
  • Interface associativity and energy absorption capability of anti-vibration
           porous Al-MM alloy core with iron alloy skin structures
    • Authors: Xu Ran; Hong-wei Sun; Li-dong Wang; Yao-ming Wu
      Pages: 730 - 736
      Abstract: Publication date: July 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 7
      Author(s): Xu Ran, Hong-wei Sun, Li-dong Wang, Yao-ming Wu
      The interface associativity and energy absorption capability of composite structure with anti-vibration porous Al-MM (cerium-rich mischmetal) alloy core and iron alloy skin were investigated. Porous aluminum core/iron alloy skin structures were fabricated considering an iron alloy tube as its shell and closed-cell porous Al-MM alloy as its core. A peeling experiment was carried out to calculate the capacity of interfacial bonding and a compression test was carried out to determine the energy absorption capability. The results showed that the addition of MM significantly enhanced both the interfacial bonding and the energy absorption capacity.

      PubDate: 2017-07-21T06:44:29Z
      DOI: 10.1016/s1006-706x(17)30110-3
       
  • Microstructures and mechanical properties of ferrite-based lightweight
           steel with different compositions
    • Authors: Reng-chong Xu; Yan-lin He; Hu Jiang; Hua Wang; Na-qiong Zhu; Xiao-gang Lu; Lin Li
      Pages: 737 - 742
      Abstract: Publication date: July 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 7
      Author(s): Reng-chong Xu, Yan-lin He, Hu Jiang, Hua Wang, Na-qiong Zhu, Xiao-gang Lu, Lin Li
      The microstructures and mechanical properties of ferrite-based lightweight steel with different compositions were investigated by tensile test, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and thermodynamic calculation (TC). It was shown that the ferrite-based lightweight steels with 5 wt. % or 8 wt. % A1 were basically composed of ferrite, austenite and κ-carbide. As the annealing temperature increased, the content of the austenite in the steel gradually increased, while the κ-carbide gradually decomposed and finally disappeared. The mechanical properties of the steel with 5 wt.% A1 and 2 wt. % Cr, composed of ferrite and Cr7C3 carbide at different annealing temperatures, were significantly inferior to those of others. The steel containing 5 wt. % Al, annealed at 820 °C for 50 s then rapidly cooled to 400 °C and held for 180 s, can obtain the best product of strength and elongation (PSE) of 31242 MPa · %. The austenite stability of the steel is better, and its PSE is higher. In addition, the steel with higher PSE has a more stable instantaneous strain hardening exponent (n value), which is mainly caused by the effect of transformation induced plasticity (TRIP). When the κ-carbide or Cr7C3 carbide existed in the microstructure of the steel, there was an obvious yield plateau in the tensile curve, while its PSE decreased significantly.

      PubDate: 2017-07-21T06:44:29Z
      DOI: 10.1016/s1006-706x(17)30111-5
       
  • Precipitated phases of superaustenitic stainless steel 654SMO
    • Authors: Zhi-gang Song; En-xiang Pu
      Pages: 743 - 749
      Abstract: Publication date: July 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 7
      Author(s): Zhi-gang Song, En-xiang Pu
      The phase diagram of superaustenitic stainless steel 654SMO was calculated by thermodynamic software and the precipitated phases in the specimens aged at 800 – 1100 °C for 1 h were studied by methods of physicochemical phase analysis, scanning electron microscopy and transmission electron microscopy. The results showed that the size of precipitated particles increased with increasing the temperature. The amount of second phases reached the maximum value at 900 °C, but decreased above 900 °C. There were about eight kinds of precipitated phases in 654SMO including σ phase, Cr2N, μ phase, χ phase, Laves phase, M23C6, M6C and M3C, in which the σ phase and Cr2 N were the dominant precipitated phases.

      PubDate: 2017-07-21T06:44:29Z
      DOI: 10.1016/s1006-706x(17)30112-7
       
  • Corrigendum to “Austenite Grain Refinement by Reverse α′→γ
           Transformation in Metastable Austenitic Manganese Steel” [J. Iron Steel
           Res. Int. 22 (2015) 157–162]
    • Authors: Jia-tao Zhang; Yu-guang Zhao; Juan Tan; Xiao-feng Xu
      First page: 750
      Abstract: Publication date: July 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 7
      Author(s): Jia-tao Zhang, Yu-guang Zhao, Juan Tan, Xiao-feng Xu


      PubDate: 2017-07-21T06:44:29Z
      DOI: 10.1016/s1006-706x(17)30113-9
       
  • Modeling of flow and temperature distribution in electroslag remelting
           withdrawal process for fabricating large-scale slab ingots
    • Authors: Wan-ming Li; Zhou-hua Jiang; Xi-min Zang; Xin Deng
      Pages: 569 - 578
      Abstract: Publication date: June 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 6
      Author(s): Wan-ming Li, Zhou-hua Jiang, Xi-min Zang, Xin Deng
      Currently, the market demands for large-scale and high-quality slab ingots are increasing significantly. A novel electroslag remelting withdrawal (ESRW) process with two series-connected electrodes and a T-shaped mould was developed to produce large-scale and high-quality slab ingots. It is very difficult to obtain large slab ingots with good surface quality and high width-to-thickness ratio. And it is not efficient for improving the quality of slab ingots by using trial-and-error-based approaches because the ESRW mechanisms are very complex. Thus, a three-dimensional mathematical model was developed to determine the relationship between process parameters and physical phenomena during the ESRW process. The relationship between the temperature field of the ESRW process and the surface quality of slab ingots was established. A good agreement between the simulated and measured temperature fields of slab ingots was obtained. The results indicate that the maximum values of current density, electromagnetic force and Joule heat all occur at the electrode-slag interface between the two electrodes. It can be found that the flow is turbulent and the temperature distribution is uniform in the slag pool with the influences of buoyancy and electromagnetic force. The wrinkles in the narrow faces of slab ingots are caused by the relatively lower input power. Increasing the electrode width and reducing the curvature can significantly improve the surface quality of slab ingots.

      PubDate: 2017-06-10T14:05:07Z
      DOI: 10.1016/s1006-706x(17)30087-0
       
  • Effect of slag composition on steel cleanliness in interstitial-free steel
    • Authors: Rui Wang; Yan-ping Bao; Yi-hong Li; Tai-quan Li; Di Chen
      Pages: 579 - 585
      Abstract: Publication date: June 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 6
      Author(s): Rui Wang, Yan-ping Bao, Yi-hong Li, Tai-quan Li, Di Chen
      Ladle slag affects steel cleanliness at the end of the Ruhrstahl-Hereaeus (RH) and holding process. The relationship between composition of ladle slag, total oxygen (TO) and inclusions was investigated using X-ray fluorescence (XRF), infrared absorption, and SEM + EDS methods. The results indicate that TO in steel at the end of RH increases linearly with increasing FeO content in slag. TO is lower when ω CaO / ω Al 2   O 3 ( C / A ) = 1.   5 - 2.   0 than that of C/A = 1.0–1.4 under an approximate content of FeO. During the holding process, irregular Al2O3 inclusions are newly generated due to slag reoxidation. Additionally, Al2O3-Ti x O inclusions are newly generated in the steel when the content of FeO is higher. By combining experimental and thermodynamic calculation results, it is determined that the slag has a good melting property within the zone of C/A=1.2–1.8 and adsorption capacity of Al2O3 when the content of SiO2 in slag is controlled at 4%–6%. The increase in the C/A ratio and the decrease of FeO content in slag can slow down the reoxidation rate.

      PubDate: 2017-06-10T14:05:07Z
      DOI: 10.1016/s1006-706x(17)30088-2
       
  • Production scheduling problems of steelmaking-continuous casting process
           in dynamic production environment
    • Authors: Zhong Zheng; Jian-yu Long; Xiao-qiang Gao
      Pages: 586 - 594
      Abstract: Publication date: June 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 6
      Author(s): Zhong Zheng, Jian-yu Long, Xiao-qiang Gao
      A concept of production scenario for the steelmaking-continuous casting production process and the mathematical description of such concept were proposed. The production scenario was described with the variation of the equipment status and the production material properties based on the executing production schedule. Then, the dynamic characteristics of the production process could be described with the evolution process of production scenario. Through analyzing the influence of the dynamic production scenario on production scheduling, three key points about the scheduling problems were identified: the problem for integrating the schedules of different batches that is non-neglected when making a schedule, the problem for matching the material flow with the schedule that should be solved when implementing a schedule, and the problem for eliminating the deviations between the initial schedule and implemented schedule that should be solved when rescheduling in a disturbed environment. Finally, a set of experiments were conducted, and the results demonstrated that making the production schedule and solving the rescheduling problem for steelmaking-continuous casting process with addressing the above three problems improve the adaptability of the schedule in dynamic environment.

      PubDate: 2017-06-10T14:05:07Z
      DOI: 10.1016/s1006-706x(17)30089-4
       
  • Continuous bending and straightening technology of Q345c slab based on
           high-temperature creep deformation
    • Authors: Long Guo; Xing-zhong Zhang; Chang-xi Feng
      Pages: 595 - 600
      Abstract: Publication date: June 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 6
      Author(s): Long Guo, Xing-zhong Zhang, Chang-xi Feng
      A new continuous bending and straightening casting curve with the aim of full using of high-temperature creep deformation was proposed. The curvature of bending and straightening segment varies as sine law with arc length. The basic arc segment is shortened significantly so that the length of bending and straightening area can be extended and the time of creep behavior can be increased. The distance from solidifying front in the slab was calculated at 1200 °C by finite element method. The maximum strain rate of new casting curve at different locations inside the slab is 6.39 × 10−5 s−1 during the bending segment and it tends to be 3.70 × 10−5 s−1 in the straightening segment. The minimum creep strain rate is 7.45 × 10−5 s−1 when the stress is 14 MPa at 1200 °C. The strain rate of new casting machine can be less than the minimum creep strain rate. Thus, there is only creep deformation and no plastic deformation in the bending and straightening process of steel continuous casting. Deformation of slabs depending on creep behavior only comes true. It is helpful for the design of the new casting machine and improvement of old casting machine depending on high temperature creep property.

      PubDate: 2017-06-10T14:05:07Z
      DOI: 10.1016/s1006-706x(17)30090-0
       
  • Crystallization behavior of blast furnace slag modified by adding iron ore
           tailing
    • Authors: Qian-qian Ren; Yu-zhu Zhang; Yue Long; Shao-sheng Chen; Zong-shu Zou; Jie Li; Chen-guang Xu
      Pages: 601 - 607
      Abstract: Publication date: June 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 6
      Author(s): Qian-qian Ren, Yu-zhu Zhang, Yue Long, Shao-sheng Chen, Zong-shu Zou, Jie Li, Chen-guang Xu
      Blast furnace (BF) slag is a by-product of the ironmaking process and could be utilized to manufacture slag fiber by adding iron ore tailing. The crystallization behavior of the modified BF slag is significant to the fibrosis process. To investigate the influence of basicity on the crystallization behavior, BF slag was modified by adding iron ore tailing at room temperature and melted at 1500 °C. FactSage simulation, X-ray diffraction, scanning electron microscopy backscattered electron imaging coupled to an energy dispersive spectrometer, and hot thermocouple technique analysis were performed to explore the crystallization behavior of the modified BF slag during the cooling process. It was found that the initial crystallization temperature increased with the increase in basicity. Melilite, anorthite, clinopyroxene, and wollastonite could be generated during the cooling process as basicity ranged from 0.7 to 0.9. Spinel could be found as one of the phases; however, wollastonite disappeared under a basicity of 1.0. The initial crystallization temperature was controlled by the crystallization of melilite during the cooling process when the basicity of the modified BF slag ranged from 0.7 to 1.0. Moreover, the cooling rate could also influence the crystallization of the modified BF slag.

      PubDate: 2017-06-10T14:05:07Z
      DOI: 10.1016/s1006-706x(17)30091-2
       
  • Numerical analysis of carbon saving potential in a top gas recycling
           oxygen blast furnace
    • Authors: Xue-feng She; Xiu-wei An; Jing-song Wang; Qing-guo Xue; Ling-tan Kong
      Pages: 608 - 616
      Abstract: Publication date: June 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 6
      Author(s): Xue-feng She, Xiu-wei An, Jing-song Wang, Qing-guo Xue, Ling-tan Kong
      Aiming at the current characteristics of blast furnace (BF) process, carbon saving potential of blast furnace was investigated from the perspective of the relationship between degree of direct reduction and carbon consumption. A new relationship chart between carbon consumption and degree of direct reduction, which can reflect more real situation of blast furnace operation, was established. Furthermore, the carbon saving potential of hydrogen-rich oxygen blast furnace (OBF) process was analyzed. Then, the policy implications based on this relationship chart established were suggested. On this basis, the method of improving the carbon saving potential of blast furnace was recycling the top gas with removal of CO2 and H2O or increasing hydrogen in BF gas and full oxygen blast. The results show that the carbon saving potential in traditional blast furnace (TBF) is only 38–56 kg · t−1 while that in OBF is 138 kg · t−1. Theoretically, the lowest carbon consumption of OBF is 261 kg · t−1 and the corresponding degree of direct reduction is 0.04. In addition, the theoretical lowest carbon consumption of hydrogen-rich OBF is 257 kg · t−1. The modeling analysis can be used to estimate the carbon savings potential in new ironmaking process and its related CO2 emissions.

      PubDate: 2017-06-10T14:05:07Z
      DOI: 10.1016/s1006-706x(17)30092-4
       
  • Steel ladle exchange models during steelmaking and continuous casting
           process
    • Authors: Bang-fu Huang; Nai-yuan Tian; Zhe Shi; Zhi-wei Ma
      Pages: 617 - 624
      Abstract: Publication date: June 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 6
      Author(s): Bang-fu Huang, Nai-yuan Tian, Zhe Shi, Zhi-wei Ma
      The models and influencing factors of steel ladles exchange during the steelmaking and continuous casting process of H steel plant were investigated. Based on analysis of the operation process and turnover time of steel ladles, relationship models for the turnover number, turnover rate, continuous casting number, number of ladles with additional turnover, and number of ladles without additional turnover were built. The turnover rules of steel ladles for one basic oxygen furnace (BOF) matching one continuous caster (CC) and two BOFs matching two CCs modes were simulated by using a Gantt chart. The models of steel ladle exchange were proposed for casting of a single CC and overlapping casting of two CCs. By analyzing the influencing factors, the following conclusions were drawn. The exchange ladle should not have the task of transporting liquid steel in the CC that stops casting earlier. The end time of the empty ladle in the CC that stops casting earlier should be earlier than the start time of the full ladle in the CC that stops casting later. After evaluating the factors influencing the start casting time, turnover cycle, casting time, continuous casting number, and overlapping time, a prioritization scheme of steel ladle exchange was proposed based on the steel grade. First, the turnover cycle and single heat casting time were determined; based on these, a reasonable ladle turnover number was calculated. Second, the turnover number and continuous casting number were optimized for maximizing the number of ladles without additional turnover. Lastly, to reduce the casting number during the overlapping time to be lower than the turnover number, the overlapping time was shortened.

      PubDate: 2017-06-10T14:05:07Z
      DOI: 10.1016/s1006-706x(17)30093-6
       
  • Hot deformation behavior of GH4945 superalloy using constitutive equation
           and processing map
    • Authors: Zhao-xia Shi; Xiao-feng Yan; Chun-hua Duan; Jin-gui Song; Ming-han Zhao; Jue Wang
      Pages: 625 - 633
      Abstract: Publication date: June 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 6
      Author(s): Zhao-xia Shi, Xiao-feng Yan, Chun-hua Duan, Jin-gui Song, Ming-han Zhao, Jue Wang
      The hot deformation behavior of GH4945 superalloy was investigated by isothermal compression test in the temperature range of 1000–1200 °C with strain rates of 0.001–10.000 s−1 to a total strain of 0.7. Dynamic recrystallization is the primary softening mechanism for GH4945 superalloy during hot deformation. The constitutive equation is established, and the calculated apparent activation energy is 458.446 kJ/mol. The processing maps at true strains of 0.2, 0.4 and 0.6 are generally similar, demonstrating that strain has little influence on processing map. The power dissipation efficiency and instability factors are remarkably influenced by deformation temperature and strain rate. The optimal hot working conditions are determined in temperature range of 1082–1131 °C with strain rates of 0.004–0.018 s−1. Another domain of 1134–1150 °C and 0.018–0.213 s−1 can also be selected as the optimal hot working conditions. The initial grains are replaced by dynamically recrystallized ones in optimal domains. The unsafe domains locate in the zone with strain rates above 0.274 s−1, mainly characterized by uneven microstructure. Hot working is not recommended in the unsafe domains.

      PubDate: 2017-06-10T14:05:07Z
      DOI: 10.1016/s1006-706x(17)30094-8
       
  • Fracture morphologies of a hot stamped steel and comparisons with several
           sheet metals
    • Authors: Shu-lin Tan; Kun Yang; Ya-nan Ding; Xian-hong Han
      Pages: 634 - 640
      Abstract: Publication date: June 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 6
      Author(s): Shu-lin Tan, Kun Yang, Ya-nan Ding, Xian-hong Han
      Hot stamping has been widely used in car industry to produce safety components. Most existing researches focused on the stamping and quenching process, but less on the mechanical properties of stamped parts. The fracture behaviors of hot stamped boron steel B1500HS have been studied, and other four commonly used sheet metals with different strengths, including Q235, TRIP780, QP980 and MS1300, were also introduced for comparison. Both uniaxial tests and mechanical trimming tests were performed, and the fracture surfaces under different stress states were observed and discussed. The SEM observations showed that the fracture models are closely related to the stress states, i. e., the tensile surfaces have ductile rupture characters while the trimming surfaces have brittle rupture characters. Compared with other steels, the quenched boron steel has smaller dimple size accompanied by shear planes in the tensile surface, and has smaller burnish zone in the trimming surface, and its cutting surface with ‘S’ like shape is also very different with others. Furthermore, two fitted empirical models were derived to describe the quantitative correlations between the average dimple diameter and the steel strength and between the percentage of burnish zone and the steel strength.

      PubDate: 2017-06-10T14:05:07Z
      DOI: 10.1016/s1006-706x(17)30095-x
       
  • Effect of vanadium on dynamic continuous cooling transformation behavior
           of medium-carbon forging steels
    • Authors: Wei-jun Hui; Na Xiao; Xiao-li Zhao; Yong-jian Zhang; Yu-feng Wu
      Pages: 641 - 648
      Abstract: Publication date: June 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 6
      Author(s): Wei-jun Hui, Na Xiao, Xiao-li Zhao, Yong-jian Zhang, Yu-feng Wu
      Dynamic continuous cooling transformation (CCT) behavior of medium-carbon forging steels microalloyed with different V contents up to 0.29% was investigated by means of dilatometric measurement, microstructural observation and hardness measurement. The results showed that the dynamic CCT diagrams were similar and the main difference was that the fields of the transformation products were shifted to the right side of the diagrams with the increase of V content, and this effect was more noticeable with an addition of 0.29% V. The Ac1 and Ac3 temperatures showed increasing trends with increasing V content, while the critical cooling rates decreased with increasing V content. The increase of V content resulted in significant increase of hardness and this tendency was enhanced with increasing cooling rate until the formation of acicular ferrite (AF). A promising approach of remarkably improving the toughness of ferritic-pearlitic medium-carbon forging steels with suitable V addition and the introduction of AF without notable penalty on its strength level was suggested.

      PubDate: 2017-06-10T14:05:07Z
      DOI: 10.1016/s1006-706x(17)30096-1
       
  • Prediction of critical forging penetration efficiency for 06Cr19Ni9NbN
           steel by dynamic recrystallization
    • Authors: Yong-xing Jiao; Jian-sheng Liu; Xing-wang Duan; Xiao-hua Zheng; Wen-wu He
      Pages: 649 - 653
      Abstract: Publication date: June 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 6
      Author(s): Yong-xing Jiao, Jian-sheng Liu, Xing-wang Duan, Xiao-hua Zheng, Wen-wu He
      In order to determine the critical forging penetration efficiency (FPE) of 06Cr19Ni9NbN steel, a new model was presented to describe critical FPE, which is significant to optimize the steel forging process. The plane strain compression tests were conducted to obtain the model and confirm its validity. The results indicated that the dynamic recrystallization (DRX) volume fraction increases and the grain size decreases with the rise of reduction ratio. Meanwhile, the compression process was simulated by DEFORM software. The tensile tests were conducted and the results demonstrated that the mechanical properties gradually become stable when the reduction ratio increases to 30%, 34% and 40% at 1200, 1100 and 1000°C, respectively. The calculated results based on this new model are consistent with experimental results, indicating that the model is suitable to predict the critical FPE for the steel.

      PubDate: 2017-06-10T14:05:07Z
      DOI: 10.1016/s1006-706x(17)30097-3
       
  • Evolution of MnS inclusions in Ti-bearing X80 pipeline steel
    • Authors: Ze-an Lv; Hong-wei Ni; Hua Zhang; Cheng-song Liu
      Pages: 654 - 660
      Abstract: Publication date: June 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 6
      Author(s): Ze-an Lv, Hong-wei Ni, Hua Zhang, Cheng-song Liu
      Studies show that manganese sulfide (MnS) inclusions in pipeline steel affect the lateral performance of steel in its rolling deformation, as well as the hydrogen-induced cracking and sulfide stress corrosion cracking resistance performance. To inhibit the precipitation of MnS and its effect on pipeline steel, a quenching experiment and a diffusion couple experiment, which investigated the evolution of MnS inclusions in Ti-bearing X80 pipeline steel, were conducted. The experimental results show that the transformation of the MnS inclusions during solidification is as follows: MnS→ titanium sulfide (TiS) → Ti4C2S2. The transition temperatures of MnS to TiS and TiS to Ti4C2S2 are 1673 and 1273 K, respectively, and the overall size of the sulfide decreased as well. Thermodynamic calculation results confirm that the transition temperatures of MnS to TiS and TiS to Ti4C2S2 are 1623 and 1203 K, respectively. When the sulfur content in the X80 pipeline steel is 0.0015%, all the sulfur in the steel can be converted into Ti4C2S2 with a titanium content of more than 0.02%.

      PubDate: 2017-06-10T14:05:07Z
      DOI: 10.1016/s1006-706x(17)30098-5
       
  • A novel sort of porous ceramic foam ball with modified surface for arsenic
           removal from aqueous solution
    • Authors: Pei-sheng Liu; Guang Cui; Yi-jiao Guo; Jing-he Chen; Zi-xuan Yang
      Pages: 661 - 668
      Abstract: Publication date: June 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 6
      Author(s): Pei-sheng Liu, Guang Cui, Yi-jiao Guo, Jing-he Chen, Zi-xuan Yang
      A sort of lightweight porous ceramic foam ball that can float on the water was recently made from the natural zeolite. The diameters of porous ball and its macroscopic pores are around 5 and 1 mm, respectively. Such ball surface could be modified to activate in different ways, i. e. loading the active alumina or desilicating the ball. Both of modified products have been investigated to adsorb the toxic ion of arsenic (As) in water effectively. This kind of porous ceramic ball was prepared by powder sintering, using natural clinoptilolite powder as the primary raw material. An active-alumina-loaded porous ceramic product was generated by sol-gel method with pseudoboehmite (AlOOH) as the main composition. The active Al atom on the porous ball surface could also be achieved by desilicating the ceramic ball in the NaOH solution. Such a desilicated product exhibited a good activity to adsorb the arsenic ion although carrying no active alumina. With this effective porous structure, the present products can be expected to become practically advantageous.

      PubDate: 2017-06-10T14:05:07Z
      DOI: 10.1016/s1006-706x(17)30099-7
       
  • Effects of vertical electromagnetic stirring on grain refinement and
           macrosegregation control of bearing steel billet in continuous casting
    • Authors: Yu Xu; En-gang Wang; Zhuang Li; An-yuan Deng
      Pages: 483 - 489
      Abstract: Publication date: May 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 5
      Author(s): Yu Xu, En-gang Wang, Zhuang Li, An-yuan Deng
      The grain refinement and macrosegregation control of GCr15 bearing steel were investigated under a type of rarely-used electromagnetic stirring, vertical electromagnetic stirring (V-EMS), in continuous casting. V-EMS can create an upward electromagnetic force and generate longitudinal loop convection, which enables the better mixing of the upper part with the lower part of the liquid steel. The results showed that applying V-EMS can enlarge the region of the equiaxed grain, decrease the secondary dendrite arm spacing (SDAS) and reduce the segregation of both carbon and sulfur. After applying V-EMS, liquid steel with a high solute concentration is brought to the dendrite tips, making the dendrite arms partially melt. The length of the dendrite fragment is approximately 1.8 mm, 10 to 12 times the SDAS. Upon increasing the amount of cooling water from 2.0 to 3.5 m3/h, the dendrite fragments exhibit an obvious aggregation following V-EMS. Finally, a criterion for dendrite fragmentation under V-EMS was derived based on the dendrite fragmentation theory of Campanella et al.

      PubDate: 2017-05-11T02:58:25Z
      DOI: 10.1016/s1006-706x(17)30073-0
       
  • Hydraulic experiment on mushroom head in bottom-blown smelting furnace
    • Authors: Fu-yong Su; Zhi Wen
      Pages: 490 - 494
      Abstract: Publication date: May 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 5
      Author(s): Fu-yong Su, Zhi Wen
      There are many bottom-blown smelting furnaces in metallurgical industry. When oxygen or air sprays from the jet nozzle into the bottom of the furnace, the melting phase will be frozen and a hemispherical porous zone with a mushroom head shape will be formed around the nozzle. The mushroom head can protect the jet nozzle and mitigate the liquid spray on the surface of melt. In order to analyze the formation process of a mushroom head in the bottom-blown smelting furnaces, a hydraulic experiment system was designed and the formation of the mushroom head was investigated by hydraulic experiment. The hydraulic experiment results show that the formation process is mainly divided into generating crushing generating process and stable mushroom head generation process. The formation of stable mushroom head requires certain thermodynamic condition and water splash is more intense without a mushroom head than with a mushroom head. The size, porosity and diameter of the mushroom head are affected by the flow rate, temperature and heat capacity of the bottom-blowing gas and the temperature of the superheat and the physical parameters of the melt.

      PubDate: 2017-05-11T02:58:25Z
      DOI: 10.1016/s1006-706x(17)30074-2
       
  • Application of insulation padding in a heavy turbine guide vane casting
    • Authors: Jin-wu Kang; Qing-xian Ma; Chi Zhang; Pei-chao Zhou; Zhong-ren Liu; Zu-liang Li; Hao Zhang
      Pages: 495 - 500
      Abstract: Publication date: May 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 5
      Author(s): Jin-wu Kang, Qing-xian Ma, Chi Zhang, Pei-chao Zhou, Zhong-ren Liu, Zu-liang Li, Hao Zhang
      To replace metal padding by insulation padding for castings can save the melt and reduce cleaning work of castings. The design of insulation padding was investigated. The equation of the modulus extension factor for insulation padding and the ratio of its thickness over the modulus of a casting were improved to determine the thickness of insulation padding. The insulation padding was designed for a turbine guide vane casting weighing 3. 5 t. A sound casting was obtained with 750 kg steel saved. On the other side, the casting obviously expanded at the interface with the insulation padding, which is perhaps the reason that the use of insulation padding has been suspended for many years. To avoid the expansion of insulation padding, a shielding layer made of a kind of material of good fire resistance was adopted to prevent the insulation layer from touching the melt. The shielding layer serves as a cushion of heat and expansion during solidification process so as to resist the expansion of castings and guarantee the feeding effect at the same time. Furthermore, insulation padding can be placed by a certain offset into the mold cavity so as to counteract the expansion of castings.

      PubDate: 2017-05-11T02:58:25Z
      DOI: 10.1016/s1006-706x(17)30075-4
       
  • Thermal analysis of walls in a new-type billet caster tundish with a
           vacuum shell
    • Authors: Jian-bo Xie; Jian-an Zhou; Lan-hua Zhou; Bao Wang; Hua Zhang
      Pages: 501 - 507
      Abstract: Publication date: May 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 5
      Author(s): Jian-bo Xie, Jian-an Zhou, Lan-hua Zhou, Bao Wang, Hua Zhang
      To reduce thermal loss from molten steel in a tundish during continuous casting production, a new tundish fabricated by welding radiation-proof steel plates onto the steel plates of the exterior walls of a billet caster tundish was proposed. This new tundish was used to investigate the effect of pressures inside the vacuum chamber on the uniformity of the temperature of molten steel and the thermal conditions of the vacuum layer. The results show that the conversion radiation coefficient is not sensitive to pressure and its value at high temperatures is merely 1.5 times greater than that at low temperatures. Pressure is the key factor affecting additional factor of conversion convection. This factor is more than 100 times greater at 105 Pa than at 102 Pa, and the temperature at inner points at 102 Pa is, on average, 4 K higher than that at 105 Pa. Meanwhile, the local temperature difference of the inlet at 102 Pa is 1 K higher than that at 105 Pa. Thus, the proposed vacuum billet caster tundish can achieve low superheat teeming of steel because of the thermal preservation capability of the vacuum, which helps to reduce the tapping temperature and improve the uniformity of the temperature of steel.

      PubDate: 2017-05-11T02:58:25Z
      DOI: 10.1016/s1006-706x(17)30076-6
       
  • Tailored properties of a novelly-designed press-hardened 22MnMoB steel
    • Authors: Ming-bo Zhou; Jing-lin Tang; Jie Yang; Cun-yu Wang
      Pages: 508 - 512
      Abstract: Publication date: May 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 5
      Author(s): Ming-bo Zhou, Jing-lin Tang, Jie Yang, Cun-yu Wang
      A novel 22MnMoB hot stamping steel was designed. The continuous cooling transformation (CCT) measurement of the 22MnMoB steel showed that the ferrite-bainite microstructure could be obtained at cooling rates lower than 25 °C/s, and the complete martensite structure required the cooling rate higher than 30 °C/s. The experiments with non-uniform die temperatures were carried out to obtain tailored properties. The results showed that strength of 1411 MPa and elongation of 6% could be obtained in the hard zone, and strength of 916 MPa and elongation of 9% could be obtained in the soft zone, which can be realized by controlling the die temperature at 400 °C. The transition zone was found smooth and could be beneficial to reduce the stress concentration and therefore improve the performance of components.

      PubDate: 2017-05-11T02:58:25Z
      DOI: 10.1016/s1006-706x(17)30077-8
       
  • Microstructural evolution and mechanical properties of a new Ni-based
           heat-resistant alloy during aging at 750 °C
    • Authors: Zhong-liang Tian; Sen-bao Jiang; Zheng-zong Chen; Han-sheng Bao; Zheng-dong Liu
      Pages: 513 - 519
      Abstract: Publication date: May 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 5
      Author(s): Zhong-liang Tian, Sen-bao Jiang, Zheng-zong Chen, Han-sheng Bao, Zheng-dong Liu
      Microstructural evolution and mechanical properties of a new candidate Ni-based heat-resistant alloy for advanced ultra-supercritical (A-USC) steam turbine rotors were investigated during aging at 750 °C up to 10000 h. The evolutions of γ′ particles inside austenitic grain and M23 C6 carbides along grain boundaries were characterized according to their morphologies, distributions, and growth kinetics. Mean radius of the γ′ spherical particles grew from 20.3 to 90.0 nm after aging for 10000 h, and the corresponding coarsening behavior was conformed to the law of Lifschitz-Slyosovd-Wagner (LSW). The weight fraction of γ′ particles slightly increased from 10.0 to 12.0 wt. % after aging of long duration at 750 °C. The Cr-rich M23C6 carbides discontinuously precipitated along grain boundaries, while other detrimental phases were not formed during the aging treatment, and hence the strength of grain boundary was enhanced by these discontinuously distributed carbides. The critical size of γ′ had a direct influence on the maximum hardness of this alloy. Moreover, this alloy presented a good impact toughness for the safety after long time aging at high temperature.

      PubDate: 2017-05-11T02:58:25Z
      DOI: 10.1016/s1006-706x(17)30078-x
       
  • Effect of vanadium on modification of inclusions in Mn- and Si-deoxidized
           steel during heat treatment at 1473 K
    • Authors: Cheng-song Liu; Xiao-qin Liu; Hong-wei Ni; Shu-feng Yang; Jing-she Li; Fei Ye
      Pages: 520 - 528
      Abstract: Publication date: May 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 5
      Author(s): Cheng-song Liu, Xiao-qin Liu, Hong-wei Ni, Shu-feng Yang, Jing-she Li, Fei Ye
      The effect of vanadium (V) on the modification of oxide inclusions in steels with different concentrations of Mn, Si, and V was determined before and after heat treatment at 1473 K. Changes in the morphology, size, and composition of these inclusions were analyzed. Equilibrium relations between the inclusions and steels at 1873 K and 1473 K were calculated using available thermodynamic data to roughly approximate the stable oxide inclusions in the steels. The results revealed that the concentrations of V and Si in the steel are critical for controlling the modification of the inclusions during heat treatment at 1473 K. MnO-SiO2-type oxide inclusions gradually transformed into MnO-V2 O3-type or Mn-SiO2- and MnO-V2O3-type inclusions in low-Si high-V steels heat-treated for 60 min. In addition, the morphology of the inclusions changed from spherical to irregular. A Si-accumulated zone and a V-depleted zone formed close to the interface in the steel matrix. The experimental and calculation results indicated that, during the heat treatment, an interface chemical reaction occurred between the Fe-Mn-Si-V steel and the MnO-SiO2-type oxide inclusion.

      PubDate: 2017-05-11T02:58:25Z
      DOI: 10.1016/s1006-706x(17)30079-1
       
  • Effects of process parameters on fragment and refinement of
           millimeter-grade coarse grains for 316LN steel during hot cogging
    • Authors: Da-shan Sui; Hai-ming Zhang; Hong-yang Zhu; Zhe Zhu; Zhen-shan Cui
      Pages: 529 - 535
      Abstract: Publication date: May 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 5
      Author(s): Da-shan Sui, Hai-ming Zhang, Hong-yang Zhu, Zhe Zhu, Zhen-shan Cui
      The heterogeneous mixed-grain microstructure is a common defect for the heavy forging of 316LN austenitic stainless steel. Isothermal compression experiments were performed on a Gleeble-3500 thermo-mechanical simulator to investigate the effect of process parameters on the fragment and refinement of millimeter-grade coarse grains (MCGs) during hot cogging. The experimental results indicate that the stress of MCG specimens is much larger than that of fine grain (FG) ones at 1150 °C, while the stress difference between MCG and FG samples became smaller at 1200 °C. Moreover, the MCGs can be well fragmented and refined under the condition of temperature of 1200 °C, strain rate of 0.01 s−1, and reduction rate of 50%. Meanwhile, numerical simulations were conducted to study the influences of temperature, strain and strain rate on microstructure evolution. The results of experiments and simulations comprehensively demonstrate that the MCG results in the increase of deformation resistance and incompatibility of deformation, and it can be fragmented and refined at 1200 °C so that the plastic deformation energy decreases remarkably with the increase of temperature from 1150 to 1200 °C.

      PubDate: 2017-05-11T02:58:25Z
      DOI: 10.1016/s1006-706x(17)30080-8
       
  • Effects of micro-alloying and production process on precipitation
           behaviors and mechanical properties of HRB600
    • Authors: Hong-bo Pan; Meng-jiao Zhang; Wei-ming Liu; Jun Yan; Hui-ting Wang; Chang-sheng Xie; Zhan Guo
      Pages: 536 - 543
      Abstract: Publication date: May 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 5
      Author(s): Hong-bo Pan, Meng-jiao Zhang, Wei-ming Liu, Jun Yan, Hui-ting Wang, Chang-sheng Xie, Zhan Guo
      Effects of micro-alloying elements and production process on microstructure, mechanical properties and precipitates of 600 MPa grade rebars were studied by using pilot test, metallographic observation, tensile test, thermodynamic calculation and transmission electron microscopy. The results show that the tested steels are composed of ferrite and pearlite, in which the content range of pearlite is 33%–45%. For vanadium micro-alloyed steel, interphase precipitation strengthening effect of V can be promoted and the yield strength of tested steels can be increased with increasing V content and decreasing finishing rolling temperature. The temperature of terminated cooling should be more than 700 °C when the water cooling is used. When niobium is added to the steel, more coarse (Nb, V) C, N precipitates are generated at high temperature, so that the solid solubility of precipitated phases of vanadium is reduced and the precipitation strengthening effect of vanadium is weakened.

      PubDate: 2017-05-11T02:58:25Z
      DOI: 10.1016/s1006-706x(17)30081-x
       
  • Multi-objective optimization of gas metal arc welding parameters and
           sequences for low-carbon steel (Q345D) T-joints
    • Authors: Qing Shao; Tao Xu; Tatsuo Yoshino; Nan Song
      Pages: 544 - 555
      Abstract: Publication date: May 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 5
      Author(s): Qing Shao, Tao Xu, Tatsuo Yoshino, Nan Song
      Q345D high-quality low-carbon steel has been extensively employed in structures with stringent welding quality requirements. A multi-objective optimization of welding stress and deformation was presented to design reasonable values of gas metal arc welding parameters and sequences of Q345D T-joints. The optimized factors included continuous variables (welding current (I), welding voltage (U) and welding speed (v)) and discrete variables (welding sequence (S) and welding direction (D)). The concepts of the pointer and stack in Visual Basic (VB) and the interpolation method were introduced to optimize the variables. The optimization objectives included the different combinations of the angular distortion and transverse welding stress along the transverse and longitudinal distributions. Based on the design of experiments (DOE) and the polynomial regression (PR) model, the finite element (FE) results of the T-joint were used to establish the mathematical models. The Pareto front and the compromise solutions were obtained by using a multi-objective particle swarm optimization (MOPSO) algorithm. The optimal results were validated by the corresponding results of the FE method, and the error between the FE results and the two-objective results as well as that between the FE results and the three-objective optimization results were less than 17.2% and 21.5%, respectively. The influence and setting regularity of different factors were discussed according to the compromise solutions.

      PubDate: 2017-05-11T02:58:25Z
      DOI: 10.1016/s1006-706x(17)30082-1
       
  • Heat transfer performance of porous titanium
    • Authors: Shi-feng Liu; An Li; Yao-jia Ren; Dong-feng Li; Zhao-hui Zhang
      Pages: 556 - 560
      Abstract: Publication date: May 2017
      Source:Journal of Iron and Steel Research, International, Volume 24, Issue 5
      Author(s): Shi-feng Liu, An Li, Yao-jia Ren, Dong-feng Li, Zhao-hui Zhang
      Porous titanium fibre materials with different structural parameters were prepared by vacuum sintering method. The thickness, porosity and wire diameter of prepared materials were investigated to understand the effects of structural parameters on pool heat transmission performance of titanium fibre porous material. As a result, better heat transfer performance is obtained when overheating is less than 10 °C. In addition, when the wire diameter is smaller, the heat transfer is better. However, when superheating is above 10 °C, heat transfer performance can be improved by increasing the wire diameter. Moreover, thickness influences the superficial area of the prepared material and affects the thermal resistance when bubbles move inside the material; superficial area and thermal resistance are the two key factors that jointly impact the heat transfer in relation to the thickness of the materials. Experimental results also show that the materials of 3 mm in thickness exhibit the best performance for heat transmission. Furthermore, changes in porosity affect the nucleation site density and the resistance to bubble detachment; however, the nucleation site density and the resistance to bubble detachment conflict with each other. In summary, the titanium fibre porous material with a 50% porosity exhibits suitable heat transfer performance.

      PubDate: 2017-05-11T02:58:25Z
      DOI: 10.1016/s1006-706x(17)30083-3
       
 
 
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