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  Subjects -> ENVIRONMENTAL STUDIES (Total: 754 journals)
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ENVIRONMENTAL STUDIES (681 journals)            First | 1 2 3 4     

Showing 601 - 378 of 378 Journals sorted alphabetically
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)
Stochastic Environmental Research and Risk Assessment     Hybrid Journal   (Followers: 4)
Strategic Behavior and the Environment     Full-text available via subscription  
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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)
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: 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: 4)
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)
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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)
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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: 180)
Trends in Environmental Analytical Chemistry     Hybrid Journal   (Followers: 2)
Trends in Pharmacological Sciences     Full-text available via subscription   (Followers: 25)
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: 50)
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: 37)
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)
Web Ecology     Open Access   (Followers: 6)
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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
   ISSN (Print) 1006-706X
   Published by Elsevier Homepage  [3039 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
       
  • Dynamic Response of Mold Oscillator Interacting with Steel Slabs
    • Authors: Yonghui PARK; Hyunchul PARK
      Pages: 900 - 909
      Abstract: Publication date: September 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 9
      Author(s): Yonghui PARK, Hyunchul PARK
      A mathematical model to show the dynamic response of the mold oscillator was suggested. The model considered a frictional interaction between the mold oscillator and slab as several connected nodes. The governing equation considered the slab as a multi-degree-of-freedom (DoF) system, and included a hysteresis model to describe elastic-plastic behavior of the slab; the mold oscillator was given two DoF by utilizing pressure and displacement experiment data. Simulations indicate that the mold and slab execute various vibrations, and that mold oscillation marks are caused by a stick-and-slip phenomenon during intervals, in which the slab contacting the mold moves downward compared to the other slab (negative strip time). The slab shows the formation of mold oscillation marks to previous formation criterion equally when the mold velocity is faster than the casting speed about downward. The oscillation mark will grow up over 2 Hz exciting frequency with constant 4 mm stroke in simulations. Finally, the negative strip time was compared to the frictional force, hysteresis variable, and plastic force to investigate formation mechanism of the oscillation marks.

      PubDate: 2016-09-07T02:39:03Z
      DOI: 10.1016/s1006-706x(16)30137-6
       
  • Effect of Rolling Process on Microstructure and Properties of 95CrMo Drill
           Steel
    • Authors: Wei YU; Bao-sheng XIE; Ban WANG; Qing-wu CAI; Shi-xin XU
      Pages: 910 - 916
      Abstract: Publication date: September 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 9
      Author(s): Wei YU, Bao-sheng XIE, Ban WANG, Qing-wu CAI, Shi-xin XU
      In order to improve the strength and toughness of 95CrMo steel and explore a short flow process, a direct rolling process was employed, and the effect of finishing rolling process on microstructure and mechanical properties was investigated. The results show that, with the decrease of finishing rolling temperature, inter-lamellar spacing increases, the strength as well as hardness has a general increase, and secondary cementite is distributed uniformly but represents a remarkable decrease in size. Based on Hall-Petch type equation, an effective relationship of yield strength and pearlite structure parameters was established. The correlation coefficients between the measured and calculated strength were more than 0. 95, which indicated a high reliability of the relationship. By analyzing the individual strength contributions of pearlite structures, yield strength was found to have a more great dependence on pearlite inter-lamellar spacing than colony size.

      PubDate: 2016-09-07T02:39:03Z
      DOI: 10.1016/s1006-706x(16)30138-8
       
  • Thermal Behavior and Kinetics of Raw/Pyrolytic Wood and Coal Blends during
           Co-combustion Process
    • Authors: Jian DING; Qing-cai LIU; Li-jun JIANG; Guo-qing LIU; Shan REN; Jian YANG; Lu YAO; Fei MENG
      Pages: 917 - 923
      Abstract: Publication date: September 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 9
      Author(s): Jian DING, Qing-cai LIU, Li-jun JIANG, Guo-qing LIU, Shan REN, Jian YANG, Lu YAO, Fei MENG
      The thermal properties of raw wood (RW) biomass, corresponding pyrolytic wood (PW) biomass, and their blends with anthracite coal (AC) were evaluated under combustion conditions with a thermogravimetric analysis (TGA) method. The blending ratios of the biomass with AC ranging from 0 to 100 mass% were taken into consideration to investigate the thermal behavior and kinetics of these blends during their co-combustion. For blends with different ratios of the RW to AC and 100% AC (100 AC), two distinct mass loss peaks related to the release or combustion process of the volatiles and the combustion of the char were noted. The addition of a higher ratio of RW or PW into AC can improve the combustion process of the blends. The thermal behavior of the RW/AC or PW/AC blends could not be characterized by a simple linear correlation of their pure material thermal behavior. With the RW/PW addition ratios varying from 25 mass% to 80 mass%, the apparent activation energy of the blends gradually decreased from 48. 46 to 34. 93 kJ/mol and from 82. 74 to 37. 81 kJ/mol for the RW/AC and PW/AC blends, respectively, with high correlation coefficient (R 2) values ranging from 0. 9956 to 0. 9984.

      PubDate: 2016-09-07T02:39:03Z
      DOI: 10.1016/s1006-706x(16)30139-x
       
  • Oxidation and Induration Characteristics of Pellets Made from Western
           Australian Ultrafine Magnetite Concentrates and Its Utilization Strategy
    • Authors: Cong-cong YANG; De-qing ZHU; Jian PAN; Bin-zhi ZHOU; Hu XUN
      Pages: 924 - 932
      Abstract: Publication date: September 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 9
      Author(s): Cong-cong YANG, De-qing ZHU, Jian PAN, Bin-zhi ZHOU, Hu XUN
      Western Australian magnetite concentrates normally have ultrafine granularity and much higher specific surface areas than Chinese magnetite concentrates owing to the significant pre-grinding and beneficiation for saleable iron grade. Such characteristics will inevitably affect the subsequent pelletization process. However, very few investigations have been done before. Thus, the oxidation and induration characteristics of pellet made from a Western Australian ultrafine magnetite concentrate were revealed by conducting routine preheating-roasting tests in an electric tube furnace and investigating the microstructure of fired pellets under an optical microscope in comparison with that of pellets made from typical Chinese magnetite concentrate. The liquidus regions of CaO-SiO2-Fe2CO3 and CaO-SiO2-Al2O3 ternary systems in air at various temperatures were calculated by FactSage software to explain the importance of liquid phase in the consolidation of fired pellets. The results show that pellet made from ultrafine magnetite concentrate possesses better oxidability and preheating performance than that made from Chinese magnetite concentrate. However, it has inferior roasting performance, usually requiring conditions of roasting at 1280 °C for at least 30 min to acquire sufficiently high compressive strength, which are attributed to higher temperature sensitivity caused by its smaller particle size and less formation of liquid phase because of low impurities like CaO and Al2O3 in raw materials. Correspondingly, its roasting performance can be significantly improved by blending with Chinese magnetite concentrates or increasing the pellet basicity (w CaO/w SiO2). By comprehensive evaluation, blending with Chinese iron ore concentrates is an appropriate way to utilize Western Australia ultrafine magnetite concentrates.

      PubDate: 2016-09-07T02:39:03Z
      DOI: 10.1016/s1006-706x(16)30140-6
       
  • Mechanical Properties and Fracture Behavior of Cu-Co-Be Alloy after
           Plastic Deformation and Heat Treatment
    • Authors: Yan-jun ZHOU; Ke-xing SONG; Jian-dong XING; Zhou LI; Xiu-hua GUO
      Pages: 933 - 939
      Abstract: Publication date: September 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 9
      Author(s): Yan-jun ZHOU, Ke-xing SONG, Jian-dong XING, Zhou LI, Xiu-hua GUO
      Mechanical properties and fracture behavior of Cu-0. 84Co-0. 23Be alloy after plastic deformation and heat treatment were comparatively investigated. Severe plastic deformation by hot extrusion and cold drawing was adopted to induce large plastic strain of Cu-0. 84Co-0. 23Be alloy. The tensile strength and elongation are up to 476. 6 MPa and 18%, respectively. The fractured surface consists of deep dimples and micro-voids. Due to the formation of supersaturated solid solution on the Cu matrix by solution treatment at 950 °C for 1 h, the tensile strength decreased to 271. 9 MPa, while the elongation increased to 42%. The fracture morphology is parabolic dimple. Furthermore, the tensile strength increased significantly to 580. 2 MPa after aging at 480 °C for 4 h. During the aging process, a large number of precipitates formed and distributed on the Cu matrix. The fracture feature of aged specimens with low elongation (4. 6%) exhibits an obvious brittle intergranular fracture. It is confirmed that the mechanical properties and fracture behavior are dominated by the microstructure characteristics of Cu-0. 84Co-0. 23Be alloy after plastic deformation and heat treatment. In addition, the fracture behavior at 450 °C of aged Cu-0. 84Co-0. 23Be alloy was also studied. The tensile strength and elongation are 383. 6 MPa and 11.2%, respectively. The fractured morphologies are mainly candy-shaped with partial parabolic dimples and equiaxed dimples. The fracture mode is multi-mixed mechanism that brittle intergranular fracture plays a dominant role and ductile fracture is secondary.

      PubDate: 2016-09-07T02:39:03Z
      DOI: 10.1016/s1006-706x(16)30141-8
       
  • Constitutive Model of Warm Deformation Behavior of Medium Carbon Steel
    • Authors: Hong-bin LI; Yun-li FENG; Tao YAN; En-lin YU
      Pages: 940 - 948
      Abstract: Publication date: September 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 9
      Author(s): Hong-bin LI, Yun-li FENG, Tao YAN, En-lin YU
      The compressive behaviors of medium carbon steel specimens were investigated over a wide range of temperatures and strain rates using a Gleeble-3500 thermo-simulation machine. The results show that the flow stress increased with strain at first, and then gradually decreased after reaching a peak value. The flow stress softening rate at a high strain rate was larger than that at a low strain rate. The effects of deformation heating and friction on flow stress were analyzed. A new friction correction method, wherein the effect of strain on frictional coefficient was considered, was established here. The stresses revised by the new method deviated from the measured stresses with increasing strain. Meanwhile, the apparent frictional coefficient variation law with strain was obtained. The frictional coefficient increased as the strain increased and then slightly decreased after maintaining a constant value. The stress was corrected by considering deformation heating. The accuracy of the temperature correction method was verified using a special experiment. The results of the verification experiment show that the temperature correction method exhibited a good accuracy in calculating the variation of stress caused by deformation heating. A constitutive model considering strain was proposed here to describe the deformation behaviors. Compared with experimental data, the modified constitutive model exhibited a good accuracy as to constitutive correlation.

      PubDate: 2016-09-07T02:39:03Z
      DOI: 10.1016/s1006-706x(16)30142-x
       
  • Tailoring of Mechanical Properties of Indirect Hot Stamping Steel Tubes by
           Laser Assisted Local Rapid Heating
    • Authors: Mahmudun Nabi CHOWDHURY; Ju-ri KIM; Sung-tae HONG; Jin-wook JUNG; Heung-nam HAN; Sang-woo SO
      Pages: 949 - 954
      Abstract: Publication date: September 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 9
      Author(s): Mahmudun Nabi CHOWDHURY, Ju-ri KIM, Sung-tae HONG, Jin-wook JUNG, Heung-nam HAN, Sang-woo SO
      The effect of laser assisted local heating on the mechanical properties of a hot stamping steel tube was investigated. A heated region with a spiral shape was generated on the surface of the tube by combining the linear movement of the laser and the rotation of the tube. The results of axial crush tests show that the laser assisted local heating can be effectively used to modify the mechanical performance of the tube. A microstructural analysis confirms that the laser locally induces a martensitic phase transformation in the heated region and results in inhomogeneous microstructures along the length of the tube.

      PubDate: 2016-09-07T02:39:03Z
      DOI: 10.1016/s1006-706x(16)30143-1
       
  • Corrosion Behavior of Welded Joints for Cargo Oil Tanks of Crude Oil
           Carrier
    • Authors: Jin-shan WEI; Yan-chang QI; Zhi-ling TIAN; Yun PENG
      Pages: 955 - 962
      Abstract: Publication date: September 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 9
      Author(s): Jin-shan WEI, Yan-chang QI, Zhi-ling TIAN, Yun PENG
      E32 grade corrosion resistant steel was welded with welding wires with three different S contents. The microstructure, mechanical properties, inclusions, and corrosion behavior of welded joint were investigated. The joint coupon corrosion test and potentiodynamic polarization test were carried out under the simulated corrosion environment of the inner bottom plates of cargo oil tanks. The pitting initiation and propagation mechanism of the weld metal were studied by scanning electron microscopy and infinite focus. The results indicated that the microstructures of three kinds of weld metals are all composed of acicular ferrite, ferrite side-plate and proeutectoid ferrite. The microstructure of heat-affected zone is composed predominantly of bainite. Joint welded with low S filler wire has good mechanical properties. S can decrease free corrosion potential and increase the corrosion tendency. The pitting initiation is oxide inclusion or sulfide-oxide inclusion complex. S can induce the formation of occluded area and promote the corrosion propagation. The chemical compositions of weld metal is similar to base metal, which can limit the galvanic corrosion between weld metal and base metal, and avoid formation of corrosion step.

      PubDate: 2016-09-07T02:39:03Z
      DOI: 10.1016/s1006-706x(16)30144-3
       
  • Tensile Deformation Behavior of Fe-Mn-Al-C Low Density Steels
    • Authors: Xiao-feng ZHANG; Hao YANG; De-Ping LENG; Long ZHANG; Zhen-yi HUANG; Guang CHEN
      Pages: 963 - 972
      Abstract: Publication date: September 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 9
      Author(s): Xiao-feng ZHANG, Hao YANG, De-Ping LENG, Long ZHANG, Zhen-yi HUANG, Guang CHEN
      Room temperature tensile tests of Fe-Mn-Al-C low density steels with four different chemical compositions were conducted to clarify the dominant deformation mechanisms. Parameters like product of strength and elongation, as well as specific strength and curves of stress-strain relations were calculated. The microstructures and tensile fracture morphologies were observed by optical microscope, scanning electron microscope and transmission electron microscope. The tensile behavior of low density steel was correlated to the microstructural evolution during plastic deformation, and the effects of elements, cooling process and heat treatment temperature on the mechanical properties of the steels were analyzed. The results show that the tensile strength of steels with different cooling modes is more than 1000 MPa. The highest tensile strength of 28Mn-12Al alloy reached 1230 MPa, with corresponding specific strength of 189. 16 MPa • cm3, • g−1, while the specific strength of 28Mn-10Al alloy was 178. 98 MPa • cm3, • g−1, and the excellent product of strength and elongation of 28Mn-8Al alloy was over 69. 2 GPa • %. A large number of ferrite reduced the ductility and strain hardening rate of the alloy, while the existence of κ carbides may improve the strength but weaken the plasticity. Some fine κ carbides appeared in the water-quenched specimen, while coarse κ carbides were observed in the air-cooled specimen. High temperature heat treatment improved the decomposition kinetics of γ phase and the diffusion rate of carbon, thus speeded up the precipitation of fine κ carbides. The dominant deformation mechanism of low density steel was planar glide, including shear-band-induced plasticity and microband-induced plasticity.

      PubDate: 2016-09-07T02:39:03Z
      DOI: 10.1016/s1006-706x(16)30145-5
       
  • Effects of Thermal Gradients and Rotational Flows on Grain Growth in 22 t
           Steel Ingots
    • Authors: Zheng CHEN; Qi-jie ZHAI; Jie-yu ZHANG; Hong-gang ZHONG
      Pages: 973 - 980
      Abstract: Publication date: September 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 9
      Author(s): Zheng CHEN, Qi-jie ZHAI, Jie-yu ZHANG, Hong-gang ZHONG
      Heavy ingots are widely used in many industrial fields. The coarse grains formed during the process of ingot solidification influence the properties and fracture behaviors of the final products. The coarse grain growth was simulated under different thermal gradients. A 30Cr2Ni4MoV steel ingot was melted in a cubic crucible with dimensions of 15 cm × 10 cm × 23 cm, and the cooling conditions on each side of the crucible were controlled by different thermal curves. The influences of thermal gradients and rotational flows on grain growth in heavy steel ingots were then investigated both numerically and experimentally. The results showed that when the amplitude of the rotation angle was 60°, the metal was solidified under a reciprocating horizontal rotational condition when the angular velocity was 10 (°)/s or 20 (°)/s. As the thermal gradient increased, the lengths of the primary columnar grains increased, and the diameters of equiaxed grains decreased. When the direction of flow rotation was perpendicular to the direction of grain growth, the columnar grain zone was nearly eliminated, and the average diameter of equiaxed grains was 0. 5 mm.

      PubDate: 2016-09-07T02:39:03Z
      DOI: 10.1016/s1006-706x(16)30146-7
       
  • Magnetic Properties of Thermally Aged Fe-Cu Alloys with Pre-deformation
    • Authors: Yi LI; Yuan-fei LI; Ben XU; Qiu-lin LI; Guo-gang SHU; Wei LIU
      Pages: 981 - 987
      Abstract: Publication date: September 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 9
      Author(s): Yi LI, Yuan-fei LI, Ben XU, Qiu-lin LI, Guo-gang SHU, Wei LIU
      Magnetic properties of thermally aged Fe-Cu alloys with pre-deformation have been evaluated to improve the understanding of using magnetic technology for the nondestructive evaluation (NDE) of irradiation embrittlement in reactor pressure vessel (RPV) steels. Fe-Cu alloys with and without pre-deformation were thermally aged at 500 °C and the changes in microstructure, mechanical properties and magnetic properties were determined. It is found that the strain-induced dislocations recover and the Cu-rich particles precipitate during the aging process, and the magnetic properties variation depends on the combined influence of these two factors. From the point of view of NDE, a fully tempered or annealed microstructure is favorable before RPV is put into service. These results improve the understanding of magnetic property evolution in actual RPV steels and help to develop NDE theory for irradiation embrittlement.

      PubDate: 2016-09-07T02:39:03Z
      DOI: 10.1016/s1006-706x(16)30147-9
       
  • Unexpected Effect of Nb Addition as a Microalloying Element on Mechanical
           Properties of δ-TRIP Steels
    • Authors: Sajad Gholami SHIRI; Seyed Ahmad Jenabali JAHROMI; Yahya PALIZDAR; Majid BELBASI
      Pages: 988 - 996
      Abstract: Publication date: September 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 9
      Author(s): Sajad Gholami SHIRI, Seyed Ahmad Jenabali JAHROMI, Yahya PALIZDAR, Majid BELBASI
      The concept of microalloying was applied to the δ-TRIP (transformation-induced plasticity) steel to investigate the feasibility of increasing the mechanical properties and understanding the effect of microalloying on the morphology and structure of the steel. A hot rolled δ-TRIP steel with three different contents of Nb (0, 0. 03, 0. 07 mass%) was subjected to the microstructural and mechanical examination. The high Al and Si concentration in these steels guaranteed the presence of the considerable δ-ferrite phase in the microstructure after the casting and the subsequent hot rolling. The obtained results showed that Nb dramatically affects the microstructure, the dynamic recovery and recrystallization behavior, as well as the grain shape and thus the stability of austenite after the thermomechanical process of hot rolling. The results also revealed an unexpected effect of Nb on the mechanical properties. The addition of Nb to the δ-TRIP steel led to a significant decrease in the ultimate strength (from 1144 to 917 MPa) and an increase in ductility (from 24% to 28%). These unconventional results could be explained by the change in the steel microstructure. The work-hardening behaviors of all samples exhibit three stages of the work-hardening rate evolution. At the stage 2, the work-hardening rate of the studied steels increased, being attributed to the TRIP effect and the transformation of austenite to martensite.

      PubDate: 2016-09-07T02:39:03Z
      DOI: 10.1016/s1006-706x(16)30148-0
       
  • Effect of Scale Formation on Copper Enrichment Behavior in Continuously
           Cast Slab
    • Authors: Nan WANG; Jin XU; Shan YU; Guang-zong ZHANG; Guang-hao CHEN; Min CHEN
      Pages: 739 - 744
      Abstract: Publication date: August 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 8
      Author(s): Nan WANG, Jin XU, Shan YU, Guang-zong ZHANG, Guang-hao CHEN, Min CHEN
      Copper enrichment behavior in continuously cast slab induced by scale formation during continuous cooling was experimentally investigated, and the effects of initial slab surface temperature and oxygen potential in atmosphere were discussed. The results showed that a loose scale adhered to the substrate was formed in H2O-N2 atmosphere at higher slab surface temperature compared to a gap formed between the scale and the steel substrate after continuous cooling in H2O-O-O2-N2 atmosphere. Under the condition of continuous cooling in H2O-N2 atmosphere, the copper enrichment occurred both within the loose scale and at the scale/steel interface with simultaneous Ni enrichment near the interface at higher slab surface temperature. The combined effects of the loose scale and nickel enrichment were thought to promote the back-migration of Cu-rich phase from the interface and occlusion within the scale layer. While in H2O-O2-N2 atmosphere, the Cu enrichment was found on the steel side and the formed gap prevented the migration of Cu to the scale.

      PubDate: 2016-08-18T15:16:54Z
      DOI: 10.1016/s1006-706x(16)30115-7
       
  • Prediction of Maximum Section Flattening of Thin-walled Circular Steel
           Tube in Continuous Rotary Straightening Process
    • Authors: Zi-qian ZHANG
      Pages: 745 - 755
      Abstract: Publication date: August 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 8
      Author(s): Zi-qian ZHANG
      Cross-sectional ovalization of thin-walled circular steel tube because of large plastic bending, also known as the Brazier effect, usually occurs during the initial stage of tube's continuous rotary straightening process. The amount of ovalization, defined as maximal cross section flattening, is an important technical parameter in tube's straightening process to control tube's bending deformation and prevent buckling. However, for the lack of special analytical model, the maximal section flattening was determined in accordance with the specified charts developed by experienced operators on the basis of experimental data; thus, it was inevitable that the localized buckling might occur during some actual straightening operations. New normal strain component formulas were derived based on the thin shell theory. Then, strain energy of thin-walled tube (per unit length) was obtained using the clastic-plastic theory. A rational model for predicting the maximal section flattening of the thin-walled circular steel tube under its straightening process was presented by the principle of minimum potential energy. The new model was validated by experiments and numerical simulations. The results show that the new model agrees well with the experiments and the numerical simulations with error of less than 10%. This new model was expected to find its potential application in thin-walled steel tube straightening machine design.

      PubDate: 2016-08-18T15:16:54Z
      DOI: 10.1016/s1006-706x(16)30116-9
       
  • An Innovative Approach to Separate Iron Oxide Concentrate from High-sulfur
           and Low-grade Pyrite Cinders
    • Authors: Yon LI; Fu-chun ZHOU; Zhao-xin ZHOU; Zhi-han TIAN; Chao YANG; Xi-ke TIAN
      Pages: 756 - 764
      Abstract: Publication date: August 2016
      Source:Journal of Iron and Steel Research, International, Volume 23, Issue 8
      Author(s): Yon LI, Fu-chun ZHOU, Zhao-xin ZHOU, Zhi-han TIAN, Chao YANG, Xi-ke TIAN
      High-sulfur and low-grade pyritc cinders are the waste products of sulfuric acid manufacturing plants. Many valuable components, such as iron oxide, are contained in pyrite cinders and difficult to be separated and purified just via the high temperature roasting process. Considering this, an innovative method including water-washing, aqua regia leaching, hydrothermal alkali activation and acid-washing was developed. And the effects of different parameters on recovery efficiency of iron oxide were systematically investigated. The optimum parameters were proposed as follows: water rinse-leaching at room temperature for 5 — 20 min, and melting at 160 °C for 2. Oh with NaOH (concentration of 30 mass%), followed by leaching with aqua regia solution (3. 0 vol. %) for 1. 0 h. After the treatment, the content of iron oxides increased from 54. 3 to 96. 0 mass% with the recovery rate exceeding 85%. Meanwhile, calcium sulphate was recovered as the high value-added products by alkali extraction liquid. Furthermore, the phase transformation and microstructure of the samples in the process were studied by physicochemical methods to reveal the separation mechanisms of different components in the pyrite cinders.

      PubDate: 2016-08-18T15:16:54Z
      DOI: 10.1016/s1006-706x(16)30117-0
       
  • 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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