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  Subjects -> ENVIRONMENTAL STUDIES (Total: 760 journals)
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ENVIRONMENTAL STUDIES (686 journals)            First | 1 2 3 4     

Showing 601 - 378 of 378 Journals sorted alphabetically
San Francisco Estuary and Watershed Science     Open Access   (Followers: 1)
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: 18)
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: 2)
Soil and Sediment Contamination: An International Journal     Hybrid Journal   (Followers: 2)
Soil and Tillage Research     Hybrid Journal   (Followers: 6)
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: 6)
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  
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: 6)
Sustainability     Open Access   (Followers: 18)
Sustainability in Environment     Open Access  
Sustainability of Water Quality and Ecology     Hybrid Journal   (Followers: 2)
Sustainable Cities and Society     Hybrid Journal   (Followers: 25)
Sustainable Development     Hybrid Journal   (Followers: 16)
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Sustainable Development Strategy and Practise     Open Access  
Sustainable Environment Research     Open Access  
Sustainable Technologies, Systems & Policies     Open Access   (Followers: 9)
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: 8)
Theoretical Ecology Series     Full-text available via subscription   (Followers: 1)
Toxicologic Pathology     Hybrid Journal   (Followers: 16)
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Toxicology in Vitro     Hybrid Journal   (Followers: 12)
Toxicology Letters     Hybrid Journal   (Followers: 12)
Toxicology Mechanisms and Methods     Hybrid Journal   (Followers: 10)
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)
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: 183)
Trends in Environmental Analytical Chemistry     Hybrid Journal   (Followers: 2)
Trends in Pharmacological Sciences     Full-text available via subscription   (Followers: 26)
Turkish Journal of Engineering and Environmental Sciences     Open Access   (Followers: 1)
UCLA Journal of Environmental Law and Policy     Open Access   (Followers: 5)
UD y la Geomática     Open Access  
Universidad y Ciencia     Open Access   (Followers: 1)
Urban Studies     Hybrid Journal   (Followers: 52)
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: 8)
Water Environment Research     Full-text available via subscription   (Followers: 38)
Water International     Hybrid Journal   (Followers: 12)
Water, Air, & Soil Pollution     Hybrid Journal   (Followers: 22)
Water, Air, & Soil Pollution : Focus     Hybrid Journal   (Followers: 9)
Waterlines     Full-text available via subscription   (Followers: 2)
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Weather, Climate, and Society     Full-text available via subscription   (Followers: 10)
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Wetlands     Hybrid Journal   (Followers: 25)
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Wildlife Australia     Full-text available via subscription   (Followers: 2)
Wiley Interdisciplinary Reviews - Climate Change     Hybrid Journal   (Followers: 18)
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: 4)
World Journal of Environmental Engineering     Open Access   (Followers: 2)
World Journal of Environmental Research     Open Access   (Followers: 1)
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]   [6 followers]  Follow
    
   Full-text available via subscription Subscription journal  (Not entitled to full-text)
   ISSN (Print) 1006-706X
   Published by Elsevier Homepage  [3040 journals]
  • Chromium Recycling from Argon-oxygen Decarburization Dust in Hot Metal
           Pre-dephosphorization Process
    • Authors: Dong-ping ZHAN; Yang-peng ZHANG; Zhou-hua JIANG; De-wei WANG; Hui-shu ZHANG
      Pages: 867 - 873
      Abstract: Publication date: September 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 9
      Author(s): Dong-ping ZHAN, Yang-peng ZHANG, Zhou-hua JIANG, De-wei WANG, Hui-shu ZHANG
      The chromium recycling from the stainless steel dust of an argon-oxygen decarburization (AOD) furnace during a hot metal pretreatment process was investigated. Experiments at different temperatures or with different amounts of AOD dusts were carried out in a laboratory furnace equipped with MoSi2 heating elements and subsequently industrial experiments were conducted in a stainless steelmaking factory, in order to study the thermodynamic mechanism of C and Si reacted with Cr2O3 to get Cr from AOD dust. The results showed that the reaction between C and Cr2O3 occurred below 1572. 18 K. Although its reducing ability was weaker than that of Si, C enabled the Cr in Cr2O3 in the AOD dust to be recycled using the Si in the slag. By combining the AOD dust added in an earlier stage, the hot metal pretreatment slag added in a later stage could not only recycle Cr from AOD dust but also remove Si, S, and P. Higher hot metal temperatures resulted in higher Cr content and lower remained P concentration in the molten iron.

      PubDate: 2016-09-07T02:39:03Z
      DOI: 10.1016/s1006-706x(16)30133-9
       
  • Direct Reduction of High-phosphorus Oolitic Hematite Ore Based on Biomass
           Pyrolysis
    • Authors: Dong-bo HUANG; Yan-bing ZONG; Ru-fei WEI; Wei GAO; Xiao-ming LIU
      Pages: 874 - 883
      Abstract: Publication date: September 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 9
      Author(s): Dong-bo HUANG, Yan-bing ZONG, Ru-fei WEI, Wei GAO, Xiao-ming LIU
      Direct reduction of high-phosphorus oolitic hematite ore based on biomass pyrolysis gases (CO, H2, and CH4), tar, and char was conducted to investigate the effects of reduction temperature, iron ore-biomass mass ratio, and reduction time on the metallization rate. In addition, the effect of particle size on the dephosphorization and iron recovery rate was studied by magnetic separation. It was determined that the metallization rate of the hematite ore could reach 99. 35% at iron ore-biomass mass ratio of 1: 0. 6, reduction temperature of 1100 °C, and reduction time of 55 min. The metallization rate and the aggregation degree of iron particles increase with the increase of reduction temperature. The particle size of direct reduced iron (DRI) has a great influence on the quality of the iron concentrate during magnetic separation. The separation degree of slag and iron was improved by the addition of 15 mass% sodium carbonate. DRI with iron grade of 89. 11%, iron recovery rate of 83. 47%, and phosphorus content of 0. 28% can be obtained when ore fines with particle size of — 10 μm account for 78. 15%.

      PubDate: 2016-09-07T02:39:03Z
      DOI: 10.1016/s1006-706x(16)30134-0
       
  • Preparation and Metallurgical Analysis of High Activity Burnt Lime for
           Steelmaking
    • Authors: Hua-qiang HAO; Yu-zhu ZHANG; Su-ju HAO; Chao-fa ZHANG; Wu-feng JIANG; Peng-hui CUI
      Pages: 884 - 890
      Abstract: Publication date: September 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 9
      Author(s): Hua-qiang HAO, Yu-zhu ZHANG, Su-ju HAO, Chao-fa ZHANG, Wu-feng JIANG, Peng-hui CUI
      Burnt lime is an important material in steelmaking and its activity degree is a key factor for liquid steel quality. The burnt lime was made by the calcination of limestone in a high pressure electric furnace. The burnt lime mineralogical phases and micro-morphologies were characterized by X-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM). The burnt lime activity degree was determined by acid-base titration, the burnt lime pore distribution was measured by mercury intrusion porosimetry (MIP), and the thermal effect of a mixture of burnt lime and slag was measured by differential scanning calorimetry (DSC). The results showed that the CaO grain size and pore size of burnt lime made under high pressure were larger than those of burnt lime made under atmospheric pressure. The CaO grain size and pore size increased and the laminate phenomenon also occurred clearly under high pressure. The activity degree of burnt lime made under high pressure was greater than that made under atmospheric pressure. The maximum activity degree was 437 mL for burnt lime made under a pressure of 0. 4 MPa. For the same ratio of CaO to SiO2, the melting temperature, hemisphere temperature and fluidity temperature of slag decreased with increasing burnt lime activity degree. The higher the activity degree the burnt lime had, the better the slag forming occurred. It was advantageous for 2CaO · SiO2 and 3CaO · SiO2 forming at lower temperatures if the burnt lime activity degree was increased.

      PubDate: 2016-09-07T02:39:03Z
      DOI: 10.1016/s1006-706x(16)30135-2
       
  • Microstructure Characteristic and Phase Evolution of Refractory Siderite
           Ore during Sodium-carbonate-added Catalyzing Carbothermic Reduction
    • Authors: Shao-jun BAI; Meng WU; Ghao LÜ; Shu-ming WEN
      Pages: 891 - 899
      Abstract: Publication date: September 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 9
      Author(s): Shao-jun BAI, Meng WU, Ghao LÜ, Shu-ming WEN
      Thermodynamic analysis of refractory siderite ore during carbothermic reduction was conducted. Microstructure characteristics and phase transformation of siderite ore during sodium-carbonate-added catalyzing carbothermic reduction were investigated. X-ray diffraction (XRD), scanning electron microscopy and energy-dispersive analysis of X-rays were used to characterize the reduced samples. Results indicate that the solid reaction between FeO and SiO2 is inevitable during carbothermic reduction and the formation of fayalite is the main hindrance to the rapid reduction of siderite. The phase transformation of present siderite ore can be described as: siderite-magnetite-metallic iron, complying with the formation of abundant fayalite. Improving the reduction temperature (≤ 1050 °C) and duration is helpful for the formation and aggregation of metallic iron. The iron particle size in the reduced ore was below 20 μm, and fayalite was abundant in the absence of sodium carbonate. With 5% Na2CO3 addition, the iron particle size in the reduced ore was generally above 50 μm, and the diffraction intensity associated with metallic iron in the XRD pattern increased. The Na2O formed from the dissociation of Na2CO3 can catalyze the carbothermic reduction of the siderite. This catalytic activity may be mainly caused by an increase in the reducing reaction activity of FeO.

      PubDate: 2016-09-07T02:39:03Z
      DOI: 10.1016/s1006-706x(16)30136-4
       
  • Modelling Effect of Circulation Flow Rate on Inclusion Removal in RH
           Degasser
    • Authors: Shu-guo ZHENG; Miao-yong ZHU
      Pages: 1243 - 1248
      Abstract: Publication date: December 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 12
      Author(s): Shu-guo ZHENG, Miao-yong ZHU
      Based on the similarity principles, a 1 : 7 scale physical model was established to study the behavior of molten steel flow and inclusion removal in a 145 t Rheinsahl-Heraeus (RH) degasser. On the basis of the quantitative measurements of the circulation flow rate and inclusion removal under various lifting gas flow rates, the effect of circulation flow rate on inclusion removal was investigated in the RH degasser. The inclusion removal rate shows the trend of first increase and then decrease twice with increasing the circulation flow rate when the circulation flow rates are smaller than 104. 7 L/min. Whereas, the inclusion removal rate increases again with the further increase in circulation flow rate when the circulation flow rate is larger than 104. 7 L/min. At lower circulation flow rates, inclusions are mainly removed by Stokes flotation to the slag/steel interface after inclusions are transferred near the slag/steel interface by the circulation flow. At higher circulation flow rates, the collision and aggregation of inclusions improves the inclusion removal efficiency. With the further increase in the circulation flow rate, inclusions are mainly removed by following the turbulent fluctuation (turbulent diffusion) to the slag/steel interface after inclusions are transferred near the slag/steel interface by the circulation flow.

      PubDate: 2016-12-23T21:05:49Z
      DOI: 10.1016/s1006-706x(16)30183-2
       
  • Transverse Bending Characteristics in U-channel Forming of Tailor Rolled
           Blank
    • Authors: Hua-wei ZHANG; Ying-ping GUAN; Jia-lu WU; Xiang-hua LIU
      Pages: 1249 - 1254
      Abstract: Publication date: December 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 12
      Author(s): Hua-wei ZHANG, Ying-ping GUAN, Jia-lu WU, Xiang-hua LIU
      Research on the formability of tailor rolled blank (TRB) is of good practical significance and application value because of the enormous potential of TRB in the aspect of automobile lightweight. However, the forming of TRB is problematic because of the varying properties; especially, springback is a main challenge. The transverse bending (bending axis is perpendicular to the rolling direction) of TRB U-channel was studied through simulation and experiment. The forming characteristics of TRB U-channel during transverse bending were analyzed. The mechanisms of forming defects, including bending springback and thickness transition zone (TTZ) movement, were revealed. On this basis, effects of blank geometric parameters on springback and TTZ movement were discussed. The results indicate that springback and TTZ movement happen during transverse bending of TRB U-channel. Nonuniform stress distribution is the most fundamental reason for the occurrence of springback of TRB during transverse bending. Annealing can eliminate nonuniform stress distribution, and thus diminish springback of TRB, especially springback on the thinner side. Therefore, springback of the whole TRB becomes more uniform. However, annealing can increase the TTZ movement. Blank thickness and TTZ position are the main factors affecting the formability of TRB U-channel during transverse bending.

      PubDate: 2016-12-23T21:05:49Z
      DOI: 10.1016/s1006-706x(16)30184-4
       
  • Recycling of High Ferrous Bauxite Reducing Slag for Synthesis of CaAl2 Si2
           O8-Al2 O3-CaAl12 O19 Composite
    • Authors: Ying-yi ZHANG; Yuan-hong QI; Zong-shu ZOU
      Pages: 1255 - 1261
      Abstract: Publication date: December 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 12
      Author(s): Ying-yi ZHANG, Yuan-hong QI, Zong-shu ZOU
      CaAl2Si2O8-Al2 O3-CaAl12O19 (CAS2-Al2 O3-CA6) composite was synthesized through reaction sintering alumina and bauxite reducing slag. The CAS2-Al2O3-CA6 composite was mainly composed of α-Al2O3, CAS2, and CA6. Gehlenite (Ca2 Al2SiO7, C2AS) phase was effectively transformed to CAS2 and CA6 through high-temperature reaction sintering under weak oxidizing atmosphere at 1400 °C for 4 h. SEM (scanning electron microscopy) and EDS (energy dispersive spectroscopy) analysis indicated that black and needle-shaped Al2 O3, rhombic or irregular polygonal-shaped FeAl2 O4, and glassy phase Ca2 Al2SiO7 disappeared after the reaction sintering. The light gray and flaky hexagon crystals of CaAl12 O19 (10 μm) and the grainy particles of Al2O3 (2–7 μm) were observed in the CAS2-Al2O3-CA6 composite. The gray crystals of CAS2 act as the binding phase and are distributed around CA6 and Al2O3. CAS2-Al2 O3-CA6 composite exhibits high refractoriness and service temperature, which are 1650 °C and 1450 °C, respectively. Reaction sintering of alumina and bauxite reducing slag is a feasible method for the synthesis of CAS2-Al2 O3-CA6 composite.

      PubDate: 2016-12-23T21:05:49Z
      DOI: 10.1016/s1006-706x(16)30185-6
       
  • Control Model of Multifunctional Hot Metal Ladles
    • Authors: Bang-fu HUANG; Nai-yuan TIAN; Zhi-wei MA; Zhe SHI; Xiao-lei ZHOU
      Pages: 1262 - 1267
      Abstract: Publication date: December 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 12
      Author(s): Bang-fu HUANG, Nai-yuan TIAN, Zhi-wei MA, Zhe SHI, Xiao-lei ZHOU
      For further research on the control model of multifunctional hot metal ladles between the ironmaking and steelmaking interface, the hot metal ladles of K steel plant were taken as the object to analyze the operation process. The factors of blast furnace supply and basic oxygen furnace demand were proposed. According to the principle of supply and demand balance, the control model of hot metal was researched under the following factor conditions: equal to, greater than, and less than 1, respectively. The distribution model of the blast furnace, steelmaking works, and online buffering was proposed. When the supply and demand factor is equal to 1, the turnover number of hot metal ladles equals 16 and the turnover cycle of hot metal ladles equals 512 min. When the factor is greater than 1, the total number of hot metal ladles is equal to the normal turnover number plus the turnover number of the cast iron machine. When the factor is less than 1, the total number of hot metal ladles is equal to the normal turnover number plus the accumulating number. Satisfactory effects were obtained by applying the control model in production. The numbers of turnover ladles and accumulating ladles were reduced.

      PubDate: 2016-12-23T21:05:49Z
      DOI: 10.1016/s1006-706x(16)30186-8
       
  • Friction Estimation and Roll Force Prediction during Hot Strip Rolling
    • Authors: Wei-gang LI; Chao LIU; Ning FENG; Xi CHEN; Xiang-hua LIU
      Pages: 1268 - 1276
      Abstract: Publication date: December 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 12
      Author(s): Wei-gang LI, Chao LIU, Ning FENG, Xi CHEN, Xiang-hua LIU
      A mathematical model of friction coefficient was proposed for the roll force calculation of hot-rolled strips. The online numerical solving method of the roll force calculation formula based on the proposed friction model was developed and illustrated by the practical calculation case. Then, the friction coefficient during hot strip rolling was estimated from the measured roll force by force model inversion. And then, the expression of friction model was proposed by analyzing the calculation process of stress state coefficient, and the model parameters were determined by the shared parameter multi-model nonlinear optimization method. Finally, the industrial experiments demonstrated the feasibility and effectiveness of the related models. The accuracy of the new roll force model based on the built friction model was much higher than that of the traditional Sims model, and it could be applied in the online hot rolling process control.

      PubDate: 2016-12-23T21:05:49Z
      DOI: 10.1016/s1006-706x(16)30187-x
       
  • Dislocation Pipe Diffusion of Mn during Annealing of 5Mn Steel
    • Authors: Jie LIN; Xi-nan LUO; Xiao-yan ZHONG; Hui-hua ZHOU; Cun-yu WANG; Jie SHI; Han DONG
      Pages: 1277 - 1280
      Abstract: Publication date: December 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 12
      Author(s): Jie LIN, Xi-nan LUO, Xiao-yan ZHONG, Hui-hua ZHOU, Cun-yu WANG, Jie SHI, Han DONG
      The dislocation pipe diffusion of Mn during annealing of 5Mn steel was experimentally investigated using transmission electron microscopy (TEM). Many dislocations existed inside the ferrite and terminated at the α/γ interface of the sample after intercritical annealing at 650 °C for 1 min. Line scans of Mn distribution demonstrated a high Mn concentration in austenite and Mn enrichment at dislocations, indicating that the dislocation pipe diffusion of Mn during intercritical annealing occurred in addition to the γ/α interface diffusion. In-situ TEM observations at 500 °C revealed that due to Ostwald ripening, large cementite precipitates grew while small cementite precipitates dissolved via Mn diffusion along the dislocations between them.

      PubDate: 2016-12-23T21:05:49Z
      DOI: 10.1016/s1006-706x(16)30188-1
       
  • Microstructure Characteristic and Electrochemical Corrosion Behavior of
           Surface Nano-crystallization Modified Carbon Steel
    • Authors: Zhao-jun CHENG; Dan SONG; Jin-yang JIANG; Jing-hua JIANG; Xiao-long MA; Kai YOU; Ai-bin MA
      Pages: 1281 - 1289
      Abstract: Publication date: December 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 12
      Author(s): Zhao-jun CHENG, Dan SONG, Jin-yang JIANG, Jing-hua JIANG, Xiao-long MA, Kai YOU, Ai-bin MA
      The surface nano-crystallization (SNC) of carbon steel was achieved via a high-speed rotating wire-brushing process. Microstructure characteristics of SNC steel were systematically studied. The SNC steel surface exhibited marked deformed plastic flows and high surface roughness. Due to the accumulated strains, a deformed gradient layer with thickness of 40–50 μm was produced, and the grain size of the topmost zone was about 50–100 nm. X-ray photoelectron spectroscopy (XPS) analysis indicated that enhanced Fe oxides and Cr oxides were generated. Electrochemical corrosion tests, including open circuit potential (OCP), electrochemical impendence spectroscopy (EIS), potentiodynamic polarization (PDP) and potentiostatic polarization (PP) were conducted to study the corrosion behavior of SNC steel in 3.5 mass% NaCl solution, where an improved corrosion resistance was observed. The resulted improvement resulted from the dominated positive effects (the attached Cr alloying element and enhanced oxide film) against the negative effects (the higher roughness and the improved corrosion activity of surface microstructure).

      PubDate: 2016-12-23T21:05:49Z
      DOI: 10.1016/s1006-706x(16)30189-3
       
  • Influence of Lamellar Direction in Pearlitic Steel Wire on Mechanical
           Properties and Microstructure Evolution
    • Authors: Tian-zhang ZHAO; Guang-liang ZHANG; Shi-hong ZHANG; Ling-yun ZHANG
      Pages: 1290 - 1296
      Abstract: Publication date: December 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 12
      Author(s): Tian-zhang ZHAO, Guang-liang ZHANG, Shi-hong ZHANG, Ling-yun ZHANG
      During cold drawing of pearlitic steel wire, the lamellar structure becomes gradually aligned with the drawing axis, which contributes to the ultra-high strength. A direct simulation about the mechanical behaviors and microstructural evolution of pearlitic lamellae was presented. A representative volume element (RVE) containing one pearlitic colony was established based on the real transmission electron microscope (TEM.) observation. The deformation of pearlitic colony during tension, shear and wire drawing were successfully simulated. The numerical results show that this metallographic texture leads to a strong anisotropy. The colony has higher yielding stress when the lamellar direction is parallel and perpendicular to the tensile direction. The lamellar evolution is strongly dependent on the initial direction and deformation mode. The formation of typical period shear bands is analyzed. In the wire drawing, the pearlitic colony at the sub-surface experiences a complex strain path: rotation, stretching along the die surface, and rotation back.

      PubDate: 2016-12-23T21:05:49Z
      DOI: 10.1016/s1006-706x(16)30190-x
       
  • Deformation Behavior of Ti-5. 6Al-4. 8Sn-2. 0Zr-1. 0Mo-0. 35Si-0. 85Nd
           Alloy in β/Quasi-β Forging Process
    • Authors: Ke-lu WANG; Shi-qiang LU; Xian-juan DONG; Xin LI; De-lai OUYANG
      Pages: 1297 - 1302
      Abstract: Publication date: December 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 12
      Author(s): Ke-lu WANG, Shi-qiang LU, Xian-juan DONG, Xin LI, De-lai OUYANG
      The hot deformation behavior of Ti-5. 6Al-4. 8Sn-2. 0Zr-l. 0Mo-0. 35Si-0. 85Nd alloy in β/quasi-β forging process was studied using isothermal compression tests over temperature range from 1040 °C to 1100 °C and strain rates form 0. 001 s−1 to 70 s−1. The results show that the flow stress and microstructure are sensitive to thermomechanical parameters. The processing maps based on the dynamic materials model at strain of 0. 3 and 0. 7 were established. The optimum deformation thermomechanical parameters at a strain of 0. 7 have two regions that exhibit the peak of power dissipation efficiency. One is the region of 1062–1100 °C and 10−3–10−1.5 s−1; and another which represents dynamic recrystallization is 1040–1045 °C and 10−18–10−09 s−1. The instable region is located where the strain rate is larger than 1 s−1 which corresponds to the mechanical instability.

      PubDate: 2016-12-23T21:05:49Z
      DOI: 10.1016/s1006-706x(16)30191-1
       
  • Laves Phase in 22Cr-27Ni-2Ti-Al Austenitic Valve Steel
    • Authors: Li-min WANG; Cheng-cheng XUE; Gang YANG; Zheng-dong LIU
      Pages: 1303 - 1308
      Abstract: Publication date: December 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 12
      Author(s): Li-min WANG, Cheng-cheng XUE, Gang YANG, Zheng-dong LIU
      The Thermo-Calc software was employed to calculate the equilibrium phase of 22Cr-27Ni-2Ti-Al austenitic valve steel, and the Laves phase in this steel was investigated after solid solution and aging by means of scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). Results show that the microstructure of the experimental steel consists of γ, γ′, Laves and NbC. Laves phases mainly precipitate on grain boundaries, with granular and fibrous morphologies. The size of the granular Laves phase is about 50–600 nm, and the fibrous Laves phase is composed of short strip Laves phases which are 300–600 nm in length and 50–150 nm in width. These two morphologies of Laves phase coarsen with increasing aging temperature, and this steel possesses the highest strength and hardness at aging temperature of 760 °C.

      PubDate: 2016-12-23T21:05:49Z
      DOI: 10.1016/s1006-706x(16)30192-3
       
  • Constitutive Modeling for Thixoforming of 9Cr18 Semi-solid Alloy and 3D
           Forecast Mapping
    • Authors: Ya-Ping LI; Ren-bo SONG; Yong-jin WANG
      Pages: 1309 - 1315
      Abstract: Publication date: December 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 12
      Author(s): Ya-Ping LI, Ren-bo SONG, Yong-jin WANG
      Thixotropic compression tests were carried out on 9Cr18 semi-solid alloy through Gleeble-1500 thermal simulation machine. According to the experiment analysis, macro separation occurred during thixoforming. The liquid film was extruded outside to the surface and solidified to form eutectic structure. The solid particles were connected with each other and underwent plastic deformation. According to the comparison between Zhou-Guan model and modified Zhou-Guan model, it could be observed that the adding of thixotropic factor played an important role in the regression and the latter one was more credible. The modified Zhou-Guan model could well describe the thixoforming behavior. 3D forecast mapping was built for 9Cr18 semi-solid alloy in thixoforming temperature range. It would provide valuable information for selecting process parameters during thixoforming in the manufacture process.

      PubDate: 2016-12-23T21:05:49Z
      DOI: 10.1016/s1006-706x(16)30193-5
       
  • Effects of Si and Cr on Complete Decarburization Behavior of High Carbon
           Steels in Atmosphere of 2 vol. % O2
    • Authors: Yang-bo LIU; Wei ZHANG; Qian TONG; Qi-song SUN
      Pages: 1316 - 1322
      Abstract: Publication date: December 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 12
      Author(s): Yang-bo LIU, Wei ZHANG, Qian TONG, Qi-song SUN
      The effects of chemical compositions, especially silicon and chromium contents, on the complete decarburization behaviors of steels in atmosphere of 2 vol. % O2 and 98 vol. % N2 were investigated by using a simultaneous thermal analyzer. Complete decarburization was observed at both 750 and 800 °C for 60Si2MnA steel, while 750 °C only for 92A steel. For GCr15 steel, no decarburization was found at 750 or 800 °C, and only partial decarburization was observed at 850 °C. It indicates that silicon promotes while chromium prevents the complete decarburization of steels in atmosphere with 2 vol. % O2. The main reason is that silicon increases while chromium reduces the equilibrium concentration of ferrite at the interface of ferrite and austenite, which results in the complete decarburization.

      PubDate: 2016-12-23T21:05:49Z
      DOI: 10.1016/s1006-706x(16)30194-7
       
  • Effects of Chromium, Vanadium and Austenite Deformation on Transformation
           Behaviors of High-strength Spring Steels
    • Authors: Gang NIU; Yin-li CHEN; Hui-bin WU; Xuan WANG; Mao-fang ZUO; Zhi-jun XU
      Pages: 1323 - 1332
      Abstract: Publication date: December 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 12
      Author(s): Gang NIU, Yin-li CHEN, Hui-bin WU, Xuan WANG, Mao-fang ZUO, Zhi-jun XU
      The phase transformation behavior during continuous cooling of high-strength spring steels containing different amounts of Cr was studied. Furthermore, the effects of combining Cr with V as well as austenite deformation on the transformation kinetics were investigated in the method of dilatometry and metallography hardness. The results showed that, with the increase of Cr, the pearlite transformation field was enlarged, the ferrite transformation field was narrowed, and the entire phase field shifted to the right. With the addition of V, the start transformation temperature of undercooling austenite (A r3) was gradually increased, but the ferrite and pearlite transformation fields were not affected. Besides, the minimum critical cooling rate of martensitic transformation was also reduced. In addition, the dynamic continuous cooling transformation (CCT) curve moves to the top left compared with the static CCT curve. The transformed microstructures showed that the addition of V and the deformation not only refined the overall transformed microstructures but also reduced the lamellar spacing of pearlite. The alloying elements Cr and V promoted the Vickers hardness. However, the effect of Cr on the Vickers hardness of martensite was stronger and the influence of V on that of pearlite was stronger. Moreover, the Vickers hardness affected by the austenite deformation was more complex and strongly depended on the transformed microstructures.

      PubDate: 2016-12-23T21:05:49Z
      DOI: 10.1016/s1006-706x(16)30195-9
       
  • Effects of Mo and Mn on Pitting Behavior of Duplex Stainless Steel
    • Authors: Li-cong AN; Jing CAO; Lin-cai WU; Hong-huan MAO; Yi-tao YANG
      Pages: 1333 - 1341
      Abstract: Publication date: December 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 12
      Author(s): Li-cong AN, Jing CAO, Lin-cai WU, Hong-huan MAO, Yi-tao YANG
      Effects of Mo and Mn elements on pitting corrosion resistance of lean duplex stainless steel in Cl− media solution have been studied. Gravimetric tests in 6 mass% FeCl3 at 35 °C and potentiodynamic analysis in 3.5 mass% NaCl were carried out. The corrosion potential (E ccor) and the pitting potential (E pit) are shifted to a more noble potential because of the presence of Mo around the pits. While the presence of Mn could sharply reduce the value of pitting resistance equivalent number (PREn) and the pits can be formed more easily. The pits are found generating at the phase with a lower PREn. The identical tendencies between the E pit and PREn of weaker phase are the same. A corrosion mechanism has been proposed to determinate pitting corrosion behavior based on microstructural observations.

      PubDate: 2016-12-23T21:05:49Z
      DOI: 10.1016/s1006-706x(16)30196-0
       
  • Hot Deformation Behavior of SA508GR. 4N Steel for Nuclear Reactor Pressure
           Vessels
    • Authors: Ning LIU; Zheng-dong LIU; Xi-kou HE; Zhi-qiang YANG; Long-teng MA
      Pages: 1342 - 1348
      Abstract: Publication date: December 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 12
      Author(s): Ning LIU, Zheng-dong LIU, Xi-kou HE, Zhi-qiang YANG, Long-teng MA
      A hot compression experiment (1073–1473 K, strain rates of 0.001–10s−1) of SA508GR. 4N low alloy steel was performed using a Gleeble-3800 thermal-mechanical simulator, and the hot deformation behavior of the steel was investigated by analyzing both the true stress-true strain curves and its microstructures. The thermal deformation equation and hot deformation activation energy (Q) of SA508GR. 4N steel were obtained by regression with a classic hyperbolic sine function. The hot processing map of SA508GR. 4N steel was also established. An empirical equation for the stress peak was described for practical applications. The SA508GR. 4N steel showed a critical Zener-Hollomon parameter (lnZ c) for dynamic recrystallization (DRX) of 37.44, below which full DRX may occur. The sensitivity of the SA508GR.4N steel increased linearly with test temperature, such that higher temperatures led to enhanced workability.

      PubDate: 2016-12-23T21:05:49Z
      DOI: 10.1016/s1006-706x(16)30197-2
       
  • Periodic Layered Structure Formed during Interfacial Reaction
    • Authors: Xian-man ZHANG; Hong-feng LUO; Liu-yong SHI
      Pages: 1127 - 1133
      Abstract: Publication date: November 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 11
      Author(s): Xian-man ZHANG, Hong-feng LUO, Liu-yong SHI
      A review of the periodic layered structure (PLS) formed during reactive diffusion was presented. The formation of PLS is a very interesting and complex phenomenon during the reactive diffusion process. It was firstly discovered occasionally. The formation of PLS has been reported in various solid state diffusion couples such as Zn/Ni3Si, Mg/SiO2, Zn/Cix Tiy and so on, and some controversial theoretical models and formation mechanism of PLS were put forward. However, there have been few reports about the PLS formed during hot dip. The development of PLS was reviewed, and the recent progress referring to the formation of PLS during the hot dip aluminizing of a novel Fe-Cr-B cast steel was especially introduced. However, not all of the borides could form PLS in their interfacial reaction with molten Al. PLS only formed at the Cr-rich Fe2B/Al interface, while Mo-rich Fe2B fractured. A general qualitative description for the interfacial reaction of Fe-Cr-B cast steel with molten Al was represented. Further investigation on the constituents of the alternating phases and formation mechanism of PLS needs to be done. At last, the development trends of PLS were proposed.

      PubDate: 2016-11-17T08:20:31Z
      DOI: 10.1016/s1006-706x(16)30167-4
       
  • Effects of Magnetic Pressure Constraint on Dynamic Deformation and
           Oscillation Behavior of Metal Free Surface
    • Authors: Yang LI; An-yuan DENG; Chuan-qi YIN; Sai-juan ZHANG; En-gang WANG
      Pages: 1134 - 1141
      Abstract: Publication date: November 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 11
      Author(s): Yang LI, An-yuan DENG, Chuan-qi YIN, Sai-juan ZHANG, En-gang WANG
      A new method was presented to constrain deformation and oscillations of liquid metal free surface by using a high frequency magnetic field. A magnetic field generator was designed to investigate its feasibility using numerical simulation and physical simulation. The results indicate the feasibility of controlling bulge deformation of liquid metal surface using magnetic pressure. Sunken deformation with a slight fluctuation occurs on the surface when magnetic pressure acts on the static liquid metal surface. The largest amplitude remains within ±0.8 mm even if current reaches 1400 A. In case of the bump-type deformation, the magnetic pressure strengthens gravity field by the superposition effect, dissipates the kinetic energy of metal flow impacting on free surface in advance, reduces the velocity of free surface, and decreases the bulge height. On the region without magnetic field, the liquid metal surface rises and tends to be flat because of the significant damping effect on surface fluctuation. The constraint strength of the magnetic pressure increases with the augment of current intensity. However, different heights of bulge deformation should have a corresponding reasonable coil current for achieving the best constraint effect.

      PubDate: 2016-11-17T08:20:31Z
      DOI: 10.1016/s1006-706x(16)30168-6
       
  • Numerical Analysis of Complicated Heat and Mass Transfer inside a Wustite
           Pellet during Reducing to Sponge Iron by H2 and CO Gaseous Mixture
    • Authors: Zare Ghadi ARIYAN; Valipour MOHAMMAD SADEGH; Biglari MOJTABA
      Pages: 1142 - 1150
      Abstract: Publication date: November 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 11
      Author(s): Zare Ghadi ARIYAN, Valipour MOHAMMAD SADEGH, Biglari MOJTABA
      Heat and mass transfer through a wustite pellet during converting to sponge iron was investigated. Pellet was reduced by a gaseous mixture containing CO and H2. The grain model was considered to simulate gas-solid reaction rate. A finite volume method (FVM) was implemented for solving the governing equations. The heat transfer mechanism around the pellet includes radiation and convection and within the pellet, effective heat transfer is considered as a blend of particles conduction and intraparticle radiation. Heat and mass distribution along the radius of pellet for two cases of reducing gases composed of pure H2 and pure CO was investigated. Local fractional reduction through the pellet was plotted to examine the heat and mass transfer behavior within the pellet and find their relevance with reduction degree. Afterwards, the impacts of pertinent parameters including gas ratio, pellet size and porosity were studied.

      PubDate: 2016-11-17T08:20:31Z
      DOI: 10.1016/s1006-706x(16)30169-8
       
  • Multivariable Dynamic Modeling for Molten Iron Quality Using Incremental
           Random Vector Functional-link Networks
    • Authors: Li ZHANG; Ping ZHOU; He-da SONG; Meng YUAN; Tian-you CHAI
      Pages: 1151 - 1159
      Abstract: Publication date: November 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 11
      Author(s): Li ZHANG, Ping ZHOU, He-da SONG, Meng YUAN, Tian-you CHAI
      Molten iron temperature as well as Si, P, and S contents is the most essential molten iron quality (MIQ) indices in the blast furnace (BF) ironmaking, which requires strict monitoring during the whole ironmaking production. However, these MIQ parameters are difficult to be directly measured online, and large-time delay exists in off-line analysis through laboratory sampling. Focusing on the practical challenge, a data-driven modeling method was presented for the prediction of MIQ using the improved multivariable incremental random vector functional-link networks (M-I-RVFLNs). Compared with the conventional random vector functional-link networks (RVFLNs) and the online sequential RVFLNs, the M-I-RVFLNs have solved the problem of deciding the optimal number of hidden nodes and overcome the overfitting problems. Moreover, the proposed M-I-RVFLNs model has exhibited the potential for multivariable prediction of the MIQ and improved the terminal condition for the multiple-input multiple-output (MIMO) dynamic system, which is suitable for the BF ironmaking process in practice. Ultimately, industrial experiments and contrastive researches have been conducted on the BF No. 2 in Liuzhou Iron and Steel Group Co. Ltd. of China using the proposed method, and the results demonstrate that the established model produces better estimating accuracy than other MIQ modeling methods.

      PubDate: 2016-11-17T08:20:31Z
      DOI: 10.1016/s1006-706x(16)30170-4
       
  • Oxidation Kinetics, Structural Changes and Element Migration during
           Oxidation Process of Vanadium-titanium Magnetite Ore
    • Authors: Feng PAN; Qing-shan ZHU; Zhan DU; Hao-yan SUN
      Pages: 1160 - 1167
      Abstract: Publication date: November 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 11
      Author(s): Feng PAN, Qing-shan ZHU, Zhan DU, Hao-yan SUN
      The oxidation kinetics, structural changes, and elements migration during the oxidation process of the vanadium-titanium magnetite (VTM) ore were analyzed. Kinetics analysis indicated that the oxidation process was controlled by diffusion control and could be divided into interface diffusion and lattice diffusion with apparent activation energy of 99.69 kJ/mol and 144.08 kJ/mol in the range of 800 – 1000 °C, respectively. The surface structure changed with the oxidization temperature as follows: dense surface→nano-sized sheets→submicron particles→molten particles. The compact structure changed into porous one because of the elements migration and enrichment. Both Fe and Ti elements migrated in the opposite direction during the oxidation process. The V element in the raw ore stably existed in the form of V5+ state, some vanadium migrated and occupied the tetrahedral sites of the hematite during the oxidation process.

      PubDate: 2016-11-17T08:20:31Z
      DOI: 10.1016/s1006-706x(16)30171-6
       
  • Effect of Noncontact Ultrasonic Technology on Solidification Quality of
           Electroslag Steel
    • Authors: Xiao-fang SHI; Li-zhong CHANG; Zheng-hai ZHU; Jian-jun WANG; Li ZHOU
      Pages: 1168 - 1176
      Abstract: Publication date: November 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 11
      Author(s): Xiao-fang SHI, Li-zhong CHANG, Zheng-hai ZHU, Jian-jun WANG, Li ZHOU
      A new electroslag furnace with ultrasonic vibration introduced through water-cooled base plate was designed and the effects of ultrasonic power on the distribution of elements, compactness and carbides in the electroslag remelting (ESR) ingots was investigated. The results showed that the distribution of elements on the entire excitation section changed with the change of ultrasonic power under experimental conditions. The statistical segregation of elements was minimum when the ultrasonic power was 500 W, whereas excessively high or excessively low power was not conducive to the uniform distribution of elements. Meanwhile, the compactness of ESR ingots gradually increased with the increase in ultrasonic power and distribution of compactness was the most uniform when ultrasonic power reached 500 W. Further increase in the ultrasonic power was not conducive to the improvement of compactness. The distribution characteristic of carbides was similar to the distribution of elements and compactness. The results indicated that the ultrasonic vibration introduced through water-cooled base plate was advantageous in improving solidification quality. However, this method needed reasonable ultrasonic power. Moreover, the effects of ultrasonic power varied for different elements.

      PubDate: 2016-11-17T08:20:31Z
      DOI: 10.1016/s1006-706x(16)30172-8
       
  • Evaluation of Zero and Sub-zero Temperature Tensile and Impact Properties
           of Quenched and Tempered Steel Weldments
    • Authors: M. BALAKRISHNAN; V. BALASUBRAMANIAN; M.A. MUTHU MANICKAM
      Pages: 1177 - 1187
      Abstract: Publication date: November 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 11
      Author(s): M. BALAKRISHNAN, V. BALASUBRAMANIAN, M.A. MUTHU MANICKAM
      Combat vehicles using armour grade quenched and tempered (Q&T) steel are needed to be operated under different climatic conditions. However, the properties meeting the room temperature test conditions may not necessarily be required to meet the low temperature operating conditions. The influences of shielded metal arc welding (SMAW) process, flux cored arc welding (FCAW) processes and test temperatures below room temperature up to–60 °C on tensile and impact toughness properties of armour grade Q&T steel welds were reported. The tensile and impact properties of the joints showed incremental trend with respect to the decrement in test temperature up to −40 °C irrespective of the welding processes used. The increment in tensile and impact properties of SMAW and FCAW joints subjected to the low temperature environment is due to plastic strain-induced phase transformation of retained austenite into martensite phase. Among the two processes, SMAW process welded joint showed better tensile and impact properties than its FCAW counterpart joints.

      PubDate: 2016-11-17T08:20:31Z
      DOI: 10.1016/s1006-706x(16)30173-x
       
  • Relationship between Hydrogen Diffusion and Blistering Nucleation and
           Growth
    • Authors: Jin-xu LI; Hang YIN; Xi-na YANG; Qian LI; Ping ZHANG; Chun-qian XIE; Yan-jing SU; Li-jie QIAO
      Pages: 1188 - 1194
      Abstract: Publication date: November 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 11
      Author(s): Jin-xu LI, Hang YIN, Xi-na YANG, Qian LI, Ping ZHANG, Chun-qian XIE, Yan-jing SU, Li-jie QIAO
      The formation condition of hydrogen blister in 18Ni maraging steel without any inner or external stress was investigated. The results show that the critical diffusible hydrogen concentration of a blister forming is about 1.4 × 10−5, which is corresponding to the current density of 30 mA/cm2 during cathodic charging in a sodium hydroxide solution. For a 0.1 cm thick sample, no matter the current density is equal to or much larger than the critical value, it spends at least about 132 h to form a hydrogen blister when hydrogen charging in single direction. It is approximately equal to the time for hydrogen atom to diffuse throughout the sample, which exactly depends on the hydrogen diffusion coefficient and the penetration depth. The very first clear suggestion was reported that the incubation period for hydrogen blister nucleation was necessary. According to the Fick’s laws, calculations show that the normalized hydrogen concentration in the escaping surface almost reaches 0.96 times of the charging surface, which means that the diffusion almost reaches a dynamic balance. A model was illustrated to describe the competitive relationship between hydrogen diffusion and blister formation.

      PubDate: 2016-11-17T08:20:31Z
      DOI: 10.1016/s1006-706x(16)30174-1
       
  • Laser Surface Alloying of Low Carbon Steel Using High-entropy Alloy
           Precursors
    • Authors: Xiao-tao LIU; Wen-bin LEI; Qun-jiao WANG; Wei-ping TONG; Chang-sheng LIU; Jian-zhong CUI
      Pages: 1195 - 1199
      Abstract: Publication date: November 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 11
      Author(s): Xiao-tao LIU, Wen-bin LEI, Qun-jiao WANG, Wei-ping TONG, Chang-sheng LIU, Jian-zhong CUI
      The Al0.5 CoCrCuFeNi high-entropy alloy powders with simple face-centered-cubic (FCC) solid solution structure were introduced into the surface layer of a low carbon steel during laser surface alloying. A high performance surface layer with extremely fine martensite as the dominant phase was obtained, resulting in a great improvement in microhardness, wear resistance, and corrosion resistance. The great enhancement of microhardness and wear resistance of the laser alloyed layer is mainly due to the formation of extremely fine martensite hard phase, the solid solution strengthening of the alloying elements in supersaturated α-Fe solid solution, and the existence of size effect and strain effect under rapid solidification. The enhancement of corrosion resistance is due to the alloying of Al, Co, Ni, Cr and Cu in the laser alloyed layer.

      PubDate: 2016-11-17T08:20:31Z
      DOI: 10.1016/s1006-706x(16)30175-3
       
  • Corrosion Behavior of Fe-based Bulk Metallic Glass and In-situ
           Dendrite-reinforced Metallic Glass Matrix Composites in Acid Solution
    • Authors: Fan YANG; Sheng-feng GUO; Ai-dong LAN; Hui-jun YANG; He-feng ZHOU
      Pages: 1200 - 1205
      Abstract: Publication date: November 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 11
      Author(s): Fan YANG, Sheng-feng GUO, Ai-dong LAN, Hui-jun YANG, He-feng ZHOU
      The corrosion behavior study was conducted on a novel Fe77 Mo3, P9 C7.5 B1.5 in-situ metallic glass matrix composite (MGMC). This composite sample was developed by introduction of bcc α-Fe dendrites as reinforcing phase. The corrosion behavior of this composite was compared to its monolithic counterpart and other Fe-based alloys such as 304L and 2304L stainless steels. The corrosion resistance of MGMCs in H2SO4 solution shows inferior to that of other Fe-based alloys. Experiments suggest that Fe-BMGs samples possess better corrosion resistance property than that of Fe-MGMCs. The possible underlying reasons can be the inhomogeneity induced by the precipitation of α-Fe dendrites in the MGMCs.

      PubDate: 2016-11-17T08:20:31Z
      DOI: 10.1016/s1006-706x(16)30176-5
       
  • Fracture Characteristics of Fully Pearlitic Steel Wire in Tension and
           Torsion
    • Authors: Tian-zhang ZHAO; Guang-liang ZHANG; Shi-hong ZHANG; Ling-yun ZHANG
      Pages: 1206 - 1212
      Abstract: Publication date: November 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 11
      Author(s): Tian-zhang ZHAO, Guang-liang ZHANG, Shi-hong ZHANG, Ling-yun ZHANG
      The fracture characteristics of fully pearlitic steel wires with fine and randomly oriented lamellae have been investigated after tension and torsion, respectively. It is found that the predominant fracture mode under small pre-deformation is dimple. The analysis of the colony size and the lamellar structure near the fracture surface indicates that each dimple roots from one colony. A simulation of tensile deformation with several pearlitic colonies based on the real scanning electron microscopy (SEM) observation shows that the plastic deformation concentrates and the stress traxiality is larger at the boundaries of colonies. It demonstrates the microcracks initialize at colony boundaries. Thus, the colony size is a significant factor for fracture behaviors under small pre-deformation. On the other hand, the fracture surface is investigated after large pre-deformation via torsion. The results show that fracture characteristics vary with radius from dimples, elongated dimples to the fibrous structure. It indicates that the fracture characteristics are dependent on the pre-deformation. The fracture mode under large pre-deformation becomes an anisotropic fibrous structure instead of dimples.

      PubDate: 2016-11-17T08:20:31Z
      DOI: 10.1016/s1006-706x(16)30177-7
       
  • Solid Solute Regularity of La Atom in α-Fe Supercell by
           First-principles
    • Authors: Cai-xia WANG; Jian YANG; Sha LIU; Xiao-lei XING; Ji-bo WANG; Xue-jun REN; Qing-xiang YANG
      Pages: 1213 - 1218
      Abstract: Publication date: November 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 11
      Author(s): Cai-xia WANG, Jian YANG, Sha LIU, Xiao-lei XING, Ji-bo WANG, Xue-jun REN, Qing-xiang YANG
      The structure stability, elastic property and electronic structure of α-FT supercell with La atom were investigated by first-principles, in which, generalized gradient approximation (GGA) with the Perdew Burke Ernzerhof (PBE) was used as exchange-correlation functional. α-Fe supercells with La atom include α-Fe supercell with La atom in octahedral interstitial solid solute (La-OISS), that with La atom in tetrahedral interstitial solid solute (La-TISS) and that with La atom in substitutional solid solute (La-SSS). The results show that the La-SSS α-Fe supercell is more stable than La-OISS one. The resistance to volume change, reversible deformation and stiffness of La-OISS α-Fe supercell are stronger than those of La-SSS one. Moreover, the degrees of anisotropy and ionization in La-SSS α-Fe supercell are both stronger than those in La-OISS one. The bonding strength between La atom and Fe atom in La-SSS α-FT supercell is larger than that in La-OISS one.

      PubDate: 2016-11-17T08:20:31Z
      DOI: 10.1016/s1006-706x(16)30178-9
       
  • Oxidation Behavior of Fe-based Amorphous Ribbons
    • Authors: Shu-lan ZHANG; He-ping LIU; Xiao-tong FU
      Pages: 1219 - 1225
      Abstract: Publication date: November 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 11
      Author(s): Shu-lan ZHANG, He-ping LIU, Xiao-tong FU
      The oxidation behavior of Fe-based amorphous ribbons was tested by annealing at 380 °C in air for different time with heat treatment furnace and analyzed by X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). The mechanism of oxides formation of the amorphous ribbons was discussed in detail. The results showed that the oxides were mostly B2O2, SiO2 and Fe2O3 or FeO. With the increase of annealing time and holding temperature, the fraction of the oxides on the ribbon surface increased and the size of the oxides became larger due to the generation of new oxides and the coalescence of small oxides. The oxides have different shapes, such as round, rod and needle-shaped. Experimental results also showed that the oxides nucleated at fish scale, air pocket and impurities in priority, and the growth of the oxides was controlled by the diffusion of atoms. With the increase of the distance to the ribbon surface, the oxygen concentration decreased dramatically. Due to the low binding energy of B2O3 and the large diffusion coefficient of B atom, the B element was oxidized firstly compared with other elements. Moreover, the oxidation depths of the B2O3 and SiO2 were larger than that of Fe2O3.

      PubDate: 2016-11-17T08:20:31Z
      DOI: 10.1016/s1006-706x(16)30179-0
       
  • Effects of Rare Earth, Titanium, and Magnesium Additions on
           Microstructures and Properties of High-boron Medium-carbon Alloy
    • Authors: Xiao-li SHI; Ye-hua JIANG; Rong ZHOU
      Pages: 1226 - 1233
      Abstract: Publication date: November 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 11
      Author(s): Xiao-li SHI, Ye-hua JIANG, Rong ZHOU
      In order to improve the toughness and wear resistance of high-boron medium-carbon alloy (HBMCA), a novel wear-resistant HBMCA comprising granular borocarbide was obtained by titanium, magnesium, and rare earth modifications. These modifications gave rise to greatly refined as-cast eutectic borocarbide structures and a less interconnected continuous borocarbide network. Heat treatment mostly produced broken and spheriodized borocarbides that tended to exist as isolated particles in modified HBMCA. The heat treated modified HBMCA exhibited enhanced hardness than pristine and impact toughness was improved significantly to 12.5 J/cm2. In addition, it displayed 2.39 and 1.7 times greater wear resistance than high-speed steel (HSS) and high nickel-chromium alloy steel (Cr25) at high temperature (500 °C), respectively. Here, the modification mechanisms involving Re2O3, TiN, and MgO/MgS heterogeneous nuclei were discussed.

      PubDate: 2016-11-17T08:20:31Z
      DOI: 10.1016/s1006-706x(16)30180-7
       
  • Correlation between Primary and Secondary Recrystallization Texture
           Components in Low-temperature Reheated Grain-oriented Silicon Steel
    • Authors: Gong-tao LIU; Zhi-qiao LIU; Ping YANG; Wei-min MAO
      Pages: 1234 - 1242
      Abstract: Publication date: November 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 11
      Author(s): Gong-tao LIU, Zhi-qiao LIU, Ping YANG, Wei-min MAO
      Low-temperature slab-reheated grain-oriented silicon steel is characterized by a sharp {411}<148> primary recrystallization texture. To date, the influence of this texture on secondary recrystallization is not clear. Micro-textures in primary and secondary recrystallizcd sheets of low-temperature reheated grain-oriented silicon steel were examined using electron backscatter diffraction. By comparing the textures and microstructures of specific primary recrystallized grains neighboring secondary grains with those of other primary grains, the influences of primary recrystallization textures and microstructures on the orientations of secondary grains were investigated. Results show that for low-temperature reheated grain-oriented silicon steel, the primary recrystallization sheet comprises {411}<148>, {111}<112>, and {001}<120> texture components. During secondary recrystallization, the {111}<112> primary recrystallized grains were easily consumed by abnormally grown Goss, deviated Goss, Brass, or {210}<001> grains; the {411}<148> primary recrystallized grains were more resistant to being swallowed; and the {001}<120> grains were the most resistant to being consumed. For a particular primary grain, the distribution of its surrounding grain boundaries determined how easily it is consumed during secondary recrystallization. Primary grains surrounded by 20°–15° grain boundaries were consumed much earlier than those having grain boundaries above 15°, which is in accordance with high-energy grain boundary theory. In addition, special ∑9 boundaries between {111}<148> and Goss grains move more slowly than ∑9 boundaries between {111}<112> and Goss grains, which is attributed to the different positions of <110> rotation axis with respect to the normals of grain boundaries.

      PubDate: 2016-11-17T08:20:31Z
      DOI: 10.1016/s1006-706x(16)30181-9
       
  • Numerical Simulation of Jet Behavior and Impingement Characteristics of
           Preheating Shrouded Supersonic Jets
    • Authors: Guang-sheng WEI; Rong ZHU; Ting CHENG; Fei ZHAO
      Pages: 997 - 1006
      Abstract: Publication date: October 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 10
      Author(s): Guang-sheng WEI, Rong ZHU, Ting CHENG, Fei ZHAO
      As a novel supersonic jet technology, preheating shrouded supersonic jet was developed to deliver oxygen into molten bath efficiently and affordably. However, there has been limited research on the jet behavior and impingement characteristics of preheating shrouded supersonic jets. Computational fluid dynamics (CFD) models were established to investigate the effects of main and shrouding gas temperatures on the characteristics of flow field and impingement of shrouded supersonic jet. The preheating shrouded supersonic jet behavior was simulated and measured by numerical simulation and jet measurement experiment respectively. The influence of preheating shrouded supersonic jet on gas jet penetration and fluid flow in liquid bath was calculated by the CFD model which was validated against water model experiments. The results show that the uptrend of the potential core length of shrouded supersonic jet would be accelerated with increasing the main and shrouding gas temperatures. Also, preheating supersonic jets demonstrated significant advantages in penetrating and stirring the liquid bath.

      PubDate: 2016-10-28T00:49:30Z
      DOI: 10.1016/s1006-706x(16)30150-9
       
  • Effect of MgO on Oxidation Process of Fe3O4 in Pellets
    • Authors: Qiang-jian GAO; Yan song SHEN; Xin JIANG; Hai-yan ZHENG; Feng-man SHEN; Chang-sheng LIU
      Pages: 1007 - 1011
      Abstract: Publication date: October 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 10
      Author(s): Qiang-jian GAO, Yan song SHEN, Xin JIANG, Hai-yan ZHENG, Feng-man SHEN, Chang-sheng LIU
      Induration process of oxidized pellets involves the oxidation of Fe3O4 and re-crystallization of Fe2O3. The oxidation process of Fe3O4 is significant for pellets to obtain better ambient strength. Thus, the effect of MgO on oxidation process of Fe3O4 was investigated. The unreacted core model was applied to analyze the oxidizing induration process of pellets. The experimental results show that MgO plays a negative role in the oxidation process of Fe3O4. The oxidation rate of Fe3O4 in MgO-fluxed pellets (95.0% Fe3O4 +5.0% MgO) is slower than that in standard acid pellets (100% Fe3O4). The relation between oxidation ratio of Fe3O4 and time was calculated based on the unreacted core model for both MgO-fluxed pellets and standard acid pellets. According to verification experiments, the values calculated by model coincide well with the experimental values. Therefore, the unreacted core model could be applied to describe the oxidizing induration process of pellets.

      PubDate: 2016-10-28T00:49:30Z
      DOI: 10.1016/s1006-706x(16)30151-0
       
  • Three-dimensional Numerical Simulation and Experimental Analysis of
           Austenite Grain Growth Behavior in Hot Forging Processes of 300M Steel
           Large Components
    • Authors: Jiao LUO; Ying-gang LIU; Miao-quan LI
      Pages: 1012 - 1019
      Abstract: Publication date: October 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 10
      Author(s): Jiao LUO, Ying-gang LIU, Miao-quan LI
      The microstructure models were integrated into finite element (FE) code, and a three-dimensional (3D) FE analysis on the entire hot forging processes of 300M steel large components was performed to predict the distributions of effective strain, temperature field and austenite grain size. The simulated results show that the finest grains distribute in the maximum effective strain region because large strain induces the occurrence of dynamic recrystallization. However, coarse macro-grains appear in the minimum effective strain region. Then, 300M steel forging test was performed to validate the results of FE simulation, and microstructure observations and quantitative analysis were implemented. The average relative difference between the calculated and experimental austenite grain size is 7.56%, implying that the present microstructure models are reasonable and can be used to analyze the hot forging processes of 300M steel.

      PubDate: 2016-10-28T00:49:30Z
      DOI: 10.1016/s1006-706x(16)30152-2
       
  • New Formulas of Shear Strain during Equal-channel Angular Pressing Process
           with Consideration of Influences of Velocity and Motion Trajectory
    • Authors: Dian-tao ZHANG; Zhen LI; Yun-xiang TONG; Yu-feng ZHENG; Li LI
      Pages: 1020 - 1027
      Abstract: Publication date: October 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 10
      Author(s): Dian-tao ZHANG, Zhen LI, Yun-xiang TONG, Yu-feng ZHENG, Li LI
      The influences of die parameters on shear strain were investigated by using two-dimensional finite element simulation. New formulas of shear strain were proposed. According to the results of formulas, the shear strain showed a linear dependence on the difference between internal and external fillet radius and the slope was determined by the intersection angle. The simulation results indicated that the velocities of the points from different zones were different in the specimen and the motion trajectories of different points did not follow geometrical laws. The influences of the average velocity and the motion trajectory on shear strain were incorporated in the formula to calculate the shear strain produced during equal-channel angular pressing process. The reliability of simulation results has been partially validated by experiments.

      PubDate: 2016-10-28T00:49:30Z
      DOI: 10.1016/s1006-706x(16)30153-4
       
  • Model Algorithm Research on Cooling Path Control of Hot-rolled Dual-phase
           Steel
    • Authors: Xiao-qing XU; Xiao-dong HAO; Shi-guang ZHOU; Chang-sheng LIU; Qi-fu ZHANG
      Pages: 1028 - 1034
      Abstract: Publication date: October 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 10
      Author(s): Xiao-qing XU, Xiao-dong HAO, Shi-guang ZHOU, Chang-sheng LIU, Qi-fu ZHANG
      With the development of advanced high strength steel, especially for dual-phase steel, the model algorithm for cooling control after hot rolling has to achieve the targeted coiling temperature control at the location of downcoiler whilst maintaining the cooling path control based on strip microstructure along the whole cooling section. A cooling path control algorithm was proposed for the laminar cooling process as a solution to practical difficulties associated with the realization of the thermal cycle during cooling process. The heat conduction equation coupled with the carbon diffusion equation with moving boundary was employed in order to simulate temperature change and phase transformation kinetics, making it possible to observe the temperature field and the phase fraction of the strip in real time. On this basis, an optimization method was utilized for valve settings to ensure the minimum deviations between the predicted and actual cooling path of the strip, taking into account the constraints of the cooling equipment's specific capacity, cooling line length, etc. Results showed that the model algorithm was able to achieve the online cooling path control for dual-phase steel.

      PubDate: 2016-10-28T00:49:30Z
      DOI: 10.1016/s1006-706x(16)30154-6
       
  • Improvement in Production Yield of Hot-rolled Coil by Controlling Process
           Cobbles
    • Authors: K. CHAKRAVARTY
      Pages: 1035 - 1043
      Abstract: Publication date: October 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 10
      Author(s): K. CHAKRAVARTY
      The yield is dependent upon many factors, such as cobbles, total scrap generation, crop loss and scale loss. It appears that the huge quantity of scale is mainly responsible for the yield loss. However, by the correlation study, it reveals that the number of cobbles is the major contributor to the yield loss. The innovation lies in changing the focus of attacking the real problem by analysing the operating data which was not surfaced earlier. The focus shifted from the furnace to the mill and the cobbles studied through the years deeply. All the analysis proved to be helpful for the future prevention of the similar kind of failure. The internal target of bringing down the number of cobbles per month in single digit was taken. This also helped in improving the maintenance practice and reducing the amount of delays significantly. The yield was improved by 0.93%.

      PubDate: 2016-10-28T00:49:30Z
      DOI: 10.1016/s1006-706x(16)30155-8
       
  • Effect of Sn on Corrosion Behavior of Ultra-pure 17 mass% Cr Ferritic
           Stainless Steels in Sulphuric Acid
    • Authors: Xiang-jun ZHANG; Fei GAO; Zhen-yu LIU
      Pages: 1044 - 1053
      Abstract: Publication date: October 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 10
      Author(s): Xiang-jun ZHANG, Fei GAO, Zhen-yu LIU
      The effect of Sn on corrosion behavior of ferritic stainless steels in 20 mass% H2SO4 was investigated by alternating current and direct current electrochemical methods and gravimetric tests at 25 °C. The results show that Sn can effectively improve general corrosion resistance of ferritic stainless steels in H2SO4, mainly due to highly raised hydrogen evolution overpotential which is in favour of strong suppression of hydrogen evolution reaction, and inhibitive effect of dissolved Sn2+ on elementary anodic reactions. With increasing Sn content, the better corrosion resistance can be reached. The Electrochemical Impedance Spectroscopy (EIS) includes four time constants and can be perfectly fitted by equivalent circuit: R s(C dl R ct)(Q ads R adS(R L1 (L 1 (R L2 L 2)))).

      PubDate: 2016-10-28T00:49:30Z
      DOI: 10.1016/s1006-706x(16)30156-x
       
  • Microstructural Evolution of a Hypoeutectoid Pearlite Steel under
           Rolling-sliding Contact Loading
    • Authors: Qiu-han LI; Chi ZHANG; Hu CHEN; Hao CHEN; Zhi-gang YANG
      Pages: 1054 - 1060
      Abstract: Publication date: October 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 10
      Author(s): Qiu-han LI, Chi ZHANG, Hu CHEN, Hao CHEN, Zhi-gang YANG
      To study the microstructural evolution of pearlite steel subjected to pure rolling and rolling-sliding contact loading, a hypoeutectoid pearlite steel with composition and microstructure similar to BS11 was designed and twin-disc tests of this pearlite steel were performed to simulate the wheel/rail system. After a series of twin-disc tests, optical microscope (OM) observation, scanning electron microscope (SEM) observation, X-ray diffraction (XRD), and micro-hardness tests were conducted to characterize the microstructure. Under the pure rolling contact condition, a large amount of reticular cracks emerged within 60 μm below the contact surface of the samples after 120000 revolutions. The largest deformation was approximately 200 μm below the contact surface. Under the rolling-sliding contact condition, the nodularization of pearlite within 100 μm below the contact surface was obvious. The microstructure and stress-strain distribution of the area within 2 mm below the contact surface were investigated. The distribution of micro-hardness under the contact surface varied with contact conditions. Finite element method (FEM) was used to simulate the stress-strain distribution. The results of SEM, FEM, and micro-hardness tests indicated that under the pure rolling contact condition, the maximum plastic strain was approximately 200–400 μm below the contact surface. Conversely, under the rolling-sliding contact condition, the maximum plastic strain emerged on the contact surface. Under the pure rolling contact condition, the distribution of micro-hardness was almost identical to that of the equivalent plastic strain. Under the rolling-sliding contact condition, the distribution of micro-hardness was affected by the equivalent plastic strain and tangential stress.

      PubDate: 2016-10-28T00:49:30Z
      DOI: 10.1016/s1006-706x(16)30157-1
       
  • Atmospheric Corrosion of Q235 Carbon Steel and Q450 Weathering Steel in
           Turpan, China
    • Authors: Qiang YU; Chao-fang DONG; Yue-hua FANG; Kui XIAO; Chun-yun GUO; Gang HE; Xiao-gang LI
      Pages: 1061 - 1070
      Abstract: Publication date: October 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 10
      Author(s): Qiang YU, Chao-fang DONG, Yue-hua FANG, Kui XIAO, Chun-yun GUO, Gang HE, Xiao-gang LI
      Q235 carbon steel and Q450 weathering steel were exposed to the hot and dry environment of Turpan, China for three years. The corrosion rates of both steels were calculated and compared. The morphologies of the rust layer products were observed by optical microscopy and scanning electron microscopy. Analyses of the rust layers were performed by X-ray photoelectron spectroscopy, X-ray powder diffraction, and Raman spectroscopy, and analysis results indicate that the compositions of rust are main iron rich oxide such as FeOOH, Fe3O4, and Fe2O3. The iron oxide layer content proportion was calculated through a semi-quantitative algorithm. The resistance elements (Cr, Ni, and Cu) enhanced the resistance properties of the Q450 weathering steel matrix. Moreover, the resistance elements increased the proportion of goethite crystals in the corroded rust layer.

      PubDate: 2016-10-28T00:49:30Z
      DOI: 10.1016/s1006-706x(16)30158-3
       
  • Chi Phase after Short-term Aging and Corrosion Behavior in 2205 Duplex
           Stainless Steel
    • Authors: Qi SUN; Jian WANG; Hua-bing LI; Yue LI; Ya-di HU; Jin-gang BAI; Pei-de HAN
      Pages: 1071 - 1079
      Abstract: Publication date: October 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 10
      Author(s): Qi SUN, Jian WANG, Hua-bing LI, Yue LI, Ya-di HU, Jin-gang BAI, Pei-de HAN
      Correlation between pitting corrosion behavior and chi (X) phase formed after a short-term aging (5, 10 and 15 min) at 850 °C of 2205 duplex stainless steel (DSS) was investigated using potentiodynamic polarization tests, optical microscopy, and scanning electron microscopy equipped with energy-dispersive spectrum system. Results showed that after aging for 5 min, the X phase initially precipitated at ferrite grain boundaries, developed and then became linked with prolonging aging time. The X phase was rich in Cr and Mo, resulting in formation of depleted zones nearby. The X phase could reduce corrosion resistance of OSS and slightly influence its stability, but the specimens still displayed the capacity for repassivation. Some lines of evidence showed that stable pitting corrosion initiated at the boundaries of precipitates. The X phase was selectively corroded during the first stage of corrosion and then the depleted zones nearby were attacked. In addition, the grain size and volume of precipitates also affected pit nucleation and progress, and suitable size and distribution of X phase could aggravate pit initiation at precipitate boundaries. The X phase with considerably low volume fraction and small size was not sensitive position for pit initiation.

      PubDate: 2016-10-28T00:49:30Z
      DOI: 10.1016/s1006-706x(16)30159-5
       
  • Effect of Nitrogen Content on Primary Recrystallization Behavior and
           Magnetic Property of Hi-B Steel
    • Authors: Hai-jun WANG; Bing FU; Li XIANG; Zhe RONG; Sheng-tao QIU
      Pages: 1080 - 1085
      Abstract: Publication date: October 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 10
      Author(s): Hai-jun WANG, Bing FU, Li XIANG, Zhe RONG, Sheng-tao QIU
      The effect of nitrogen content on primary recrystallization microstructure, texture and magnetic property of Hi-B steel was studied by means of optical microscopy (OM), scanning electron microscopy (SEM), and electron backscatter diffraction (EBSD). When nitrogen content increased gradually from 0.0055% to 0.0310%, the primary grain size and variation coefficient of nitrided sheet reduced from 26.85 μm, 0.590 to 18.87 μm, 0.525 – 0.565, respectively. Meanwhile, the primary recrystallization texture style of nitrided sheet was nearly identical to the texture style of decarburized sheet before nitriding treatment, but exhibiting a certain change on texture intensity. The variation of average magnetic induction value (B 8) and core loss value (P 17/50) were manifested to be M-shaped and W-shaped curves, respectively. When nitrogen content reached 0.0160%, the best value of the average magnetic property of the final product was obtained as follows: the B 8 and P 17/50 were 1.921 T and 0.968 W/kg, respectively. Meanwhile, the best performance, B 8 and P 17/50, of single sheet was 1.961 T and 0.854 W/kg.

      PubDate: 2016-10-28T00:49:30Z
      DOI: 10.1016/s1006-706x(16)30160-1
       
  • Effect of Heat Input on Cleavage Crack Initiation of Simulated Coarse
           Grain Heat-affected Zone in Microalloyed Offshore Platform Steel
    • Authors: Feng LU; Guang-ping CHENG; Feng CHAI; Tao PAN; Zhong-ran SHI; Hang SU; Cai-fu YANG
      Pages: 1086 - 1095
      Abstract: Publication date: October 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 10
      Author(s): Feng LU, Guang-ping CHENG, Feng CHAI, Tao PAN, Zhong-ran SHI, Hang SU, Cai-fu YANG
      The combined effects of martensite-austenite (MA) constituent and pearlite colony on cleavage crack initiation in the simulated coarse-grained heat-affected zone (CGHAZ) of V-N-Ti microalloyed offshore platform steel under different heat inputs were investigated. The results of welding simulation, instrumented impact test, and quantitative analysis indicated that the size of the MA constituent decreased with the increase in cooling time, and by contrast, the size of the pearlite colony increased. According to Griffith theory, the critical sizes of cleavage microcracks were calculated. With the increase of cooling time, the calculated microcrack size could be characterized by the size of the MA constituent first, and then fitted with the size of the pearlite colony. Moreover, the calculated microcrack size variation was opposite to the microcrack initiation energy. This phenomenon is probably due to the combined effects of the MA constituent and pearlite colony with increasing the cooling time of the specimen's temperature from 800 to 500 °C.

      PubDate: 2016-10-28T00:49:30Z
      DOI: 10.1016/s1006-706x(16)30161-3
       
  • Phase Stability, Elastic, Thermo-physical and Electronic Properties of
           Hexa-(Mo, Cr, W)2C from First-principles Calculations
    • Authors: Di WU; Wan-tang FU; Yong LI; Chun-xu WANG; Jing-lin TANG
      Pages: 1096 - 1103
      Abstract: Publication date: October 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 10
      Author(s): Di WU, Wan-tang FU, Yong LI, Chun-xu WANG, Jing-lin TANG
      Phase stability, elastic properties, thermo-physical properties, as well as electronic properties of hexa-(Mo, Cr, W)2C carbides were investigated by first-principles calculations. The results indicated that the Mo8C4, Mo7Cr1C4, Mo7W1C4, Mo6W2C4, and Mo6W1Cr7C4 are stable and the stability follows the sequence: Mo6 W1 Cr1 C4> Mo7 Wi C4 > Mo7 Cr1 C4 > Mo6 W2 C4 > Mo8 C1. Mo6W1Cr1C4 shows the highest stability, deformation resistance and hardness. G/B (shear modulus/bulk modulus) and Poisson's ratio of the stable hexa-(Mo, Cr, W)2C are all larger than 1.75 and 0.26, respectively, which indicates that they are all brittle. The anisotropies are mainly due to the different Vogit shear modulus/Reuss shear modulus; the mechanical anisotropy of Mo7Cr7C4 is the largest, and that of Mo8C4 is the smallest. Moreover, the obtained Debye temperature Θ D and heat capacity C p indicate that Mo6W2C4 possesses the best thermal conductivity (Θ D = 497.72 K), while Mo7Cr1C4 and Mo6W2C4 possess the largest heat capacity when the temperature is in the range of 0 – 10 K and larger than 10 K, respectively. From the electronic property analysis, the doped Cr and W atoms can not only participate in orbitals hybridization themselves but also enhance the orbitals hybridization between Mo and C atoms, which can reinforce the interatomic interactions.

      PubDate: 2016-10-28T00:49:30Z
      DOI: 10.1016/s1006-706x(16)30162-5
       
  • Characteristics of Welding Crack Defects and Failure Mode in Resistance
           Spot Welding of DP780 Steel
    • Authors: Xiao-pei WANG; Yong-qiang ZHANG; Jian-bin JU; Jian-qiang ZHANG; Jian-wei YANG
      Pages: 1104 - 1110
      Abstract: Publication date: October 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 10
      Author(s): Xiao-pei WANG, Yong-qiang ZHANG, Jian-bin JU, Jian-qiang ZHANG, Jian-wei YANG
      The mechanical properties of welded joints in resistance spot welding of DP780 steel were tested, and three different types of welding cracks in welded joints were investigated by optical microscopy, scanning electron microscopy and electron back-scattered diffraction. Finally, the failure mode of the welded joints in shear tensile test was discussed. It is found the shear tensile strength of welded joints can be greatly improved by adding preheating current or tempering current. The surface crack in welded joint is intergranular fracture, while the inner crack in welded joint is transgranular fracture, and the surface crack on the edge of the electrode imprint can be improved by adding preheating current or tempering current. The traditional failure mode criterion advised by American Welding Society is no longer suitable for DP780 spot welds and the critical nugget size suggested by Pouranvari is overestimated.

      PubDate: 2016-10-28T00:49:30Z
      DOI: 10.1016/s1006-706x(16)30163-7
       
  • Grain Growth Behavior of Inconel 625 Superalloy
    • Authors: Min LIU; Wen-jie ZHENG; Jin-zhong XIANG; Zhi-gang SONG; En-xiang PU; Han FENG
      Pages: 1111 - 1118
      Abstract: Publication date: October 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 10
      Author(s): Min LIU, Wen-jie ZHENG, Jin-zhong XIANG, Zhi-gang SONG, En-xiang PU, Han FENG
      The grain growth (GG) behavior of Inconel 625 superalloy was studied in the temperature range of 900—1250 °C and holding time range of 10—80 min. Microstructures of the alloy were characterized by optical metallography, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Grains grew obviously with either increasing temperature or extending holding time at temperatures above 1050 °C. However, at temperatures lower than 1050 °C, the GG was sluggish due to the pinning effect of carbide particles on grain boundary (GB). Threshold temperature for transition from mixed grain structure to uniform one was considered to be around 1100 °C. Once the temperatures surpassed 1200 °C, an instant increase in the grain size occurred showing no dependence on holding time. TEM analysis showed that the dominant second phase formed heterogeneously on the GB was M6C, which significantly impeded grain growth. On the basis of experimental data, the mathematical model of GG was established, which can describe GG behavior of Inconel 625 alloy during solution treatment (ST) at 1100—1250 °C. The activation energy for GG of Inconel 625 alloy was 207. 3 kJ, which suggested that the GG of Inconel 625 alloy was controlled by the process of GB diffusion.

      PubDate: 2016-10-28T00:49:30Z
      DOI: 10.1016/s1006-706x(16)30164-9
       
  • Wear Behavior of Aluminum Matrix Hybrid Composites Fabricated through
           Friction Stir Welding Process
    • Authors: Halil Ibrahim KURT; Murat ODUNCUOGLU; Ramazan ASMATULU
      Pages: 1119 - 1126
      Abstract: Publication date: October 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 10
      Author(s): Halil Ibrahim KURT, Murat ODUNCUOGLU, Ramazan ASMATULU
      Effects of friction stir processing (FSP) parameters and reinforcements on the wear behavior of 6061-T6 based hybrid composites were investigated. A mathematical formulation was derived to calculate the wear volume loss of the composites. The experimental results were contrasted with the results of the proposed model. The influences of sliding distance, tool traverse and rotational speeds, as well as graphite (Gr) and titanium carbide (TiC) volume fractions on the wear volume loss of the composites were also investigated using the prepared formulation. The results demonstrated that the wear volume loss of the composites significantly increased with increasing sliding distance, tool traverse speed, and rotational speed; while the wear volume loss decreased with increasing volume fraction of the reinforcements. A minimum wear volume loss for the hybrid composites with complex reinforcements was specified at the inclusion ratio of 50% TiC + 50% Al2O3 because of improved lubricant ability, as well as resistance to brittleness and wear. New possibilities to develop wear-resistant aluminum-based composites for different industrial applications were proposed.

      PubDate: 2016-10-28T00:49:30Z
      DOI: 10.1016/s1006-706x(16)30165-0
       
 
 
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