Subjects -> METALLURGY (Total: 59 journals)
Showing 1 - 10 of 10 Journals sorted alphabetically
Acta Metallurgica Slovaca     Open Access   (Followers: 2)
Advanced Device Materials     Open Access   (Followers: 6)
American Journal of Fluid Dynamics     Open Access   (Followers: 44)
Archives of Metallurgy and Materials     Open Access   (Followers: 9)
Asian Journal of Materials Science     Open Access   (Followers: 4)
Canadian Metallurgical Quarterly     Hybrid Journal   (Followers: 21)
Complex Metals     Open Access   (Followers: 2)
Energy Materials : Materials Science and Engineering for Energy Systems     Hybrid Journal   (Followers: 24)
Graphene and 2D Materials     Open Access   (Followers: 6)
Handbook of Ferromagnetic Materials     Full-text available via subscription   (Followers: 1)
Handbook of Magnetic Materials     Full-text available via subscription   (Followers: 2)
High Temperature Materials and Processes     Open Access   (Followers: 6)
Indian Journal of Engineering and Materials Sciences (IJEMS)     Open Access   (Followers: 11)
International Journal of Metallurgy and Alloys     Full-text available via subscription   (Followers: 2)
International Journal of Metals     Open Access   (Followers: 7)
International Journal of Minerals, Metallurgy, and Materials     Hybrid Journal   (Followers: 12)
International Journal of Mining and Geo-Engineering     Open Access   (Followers: 4)
Ironmaking & Steelmaking     Hybrid Journal   (Followers: 5)
ISIJ International - Iron and Steel Institute of Japan     Full-text available via subscription   (Followers: 26)
Izvestiya Vuzov. Poroshkovaya Metallurgiya i Funktsional’nye Pokrytiya (Proceedings of Higher Schools. Powder Metallurgy аnd Functional Coatings)     Full-text available via subscription   (Followers: 2)
JOM Journal of the Minerals, Metals and Materials Society     Hybrid Journal   (Followers: 35)
Journal of Advanced Joining Processes     Open Access  
Journal of Central South University     Hybrid Journal   (Followers: 1)
Journal of Cluster Science     Hybrid Journal  
Journal of Heavy Metal Toxicity and Diseases     Open Access  
Journal of Iron and Steel Research International     Hybrid Journal   (Followers: 11)
Journal of Materials & Metallurgical Engineering     Full-text available via subscription   (Followers: 2)
Journal of Materials Processing Technology     Hybrid Journal   (Followers: 21)
Journal of Metallurgical Engineering     Open Access   (Followers: 4)
Journal of Sustainable Metallurgy     Hybrid Journal   (Followers: 3)
Materials Science and Metallurgy Engineering     Open Access   (Followers: 7)
Metal Finishing     Full-text available via subscription   (Followers: 20)
Metallurgical and Materials Engineering     Open Access   (Followers: 7)
Metallurgical and Materials Transactions A     Hybrid Journal   (Followers: 42)
Metallurgical and Materials Transactions B     Hybrid Journal   (Followers: 32)
Metallurgical and Materials Transactions E     Full-text available via subscription   (Followers: 2)
Metallurgical Research & Technology     Full-text available via subscription  
Metallurgical Research and Technology     Full-text available via subscription   (Followers: 8)
Metallurgy and Foundry Engineering     Open Access   (Followers: 3)
Mining, Metallurgy & Exploration     Hybrid Journal  
Powder Diffraction     Full-text available via subscription   (Followers: 1)
Powder Metallurgy     Hybrid Journal   (Followers: 35)
Powder Metallurgy and Metal Ceramics     Hybrid Journal   (Followers: 7)
Powder Metallurgy Progress     Open Access   (Followers: 5)
Practical Metallography     Full-text available via subscription   (Followers: 6)
Rare Metals     Hybrid Journal   (Followers: 3)
Revista de Metalurgia     Open Access  
Revista del Instituto de Investigación de la Facultad de Ingeniería Geológica, Minera, Metalurgica y Geográfica     Open Access  
Revista Remetallica     Open Access   (Followers: 1)
Russian Metallurgy (Metally)     Full-text available via subscription   (Followers: 4)
Science and Technology of Welding and Joining     Hybrid Journal   (Followers: 8)
Steel Times lnternational     Partially Free   (Followers: 19)
Transactions of the IMF     Hybrid Journal   (Followers: 14)
Transactions of the Indian Institute of Metals     Hybrid Journal   (Followers: 5)
Tungsten     Hybrid Journal  
Universal Journal of Materials Science     Open Access   (Followers: 3)
Welding in the World     Hybrid Journal   (Followers: 8)
Welding International     Hybrid Journal   (Followers: 11)
Вісник Приазовського Державного Технічного Університету. Серія: Технічні науки     Open Access  
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Journal of Iron and Steel Research International
Journal Prestige (SJR): 0.569
Citation Impact (citeScore): 1
Number of Followers: 11  
 
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 1006-706X - ISSN (Online) 2210-3988
Published by Springer-Verlag Homepage  [2652 journals]
  • Effect of nozzle type on fluid flow, solidification, and solute transport
           in mold with mold electromagnetic stirring
    • Abstract: The mathematical model of coupling fluid flow, heat transfer, solidification, solute transport, and the electromagnetic field of the bloom in the upper part of the strand was established with three nozzle types. Then, the flow field, distribution of the temperature, solidification, and macrosegregation of carbon were investigated and compared by numerical modeling. In the case of the straight submerged entry nozzle (SEN), the molten steel flows down deep into the liquid pool, and the depth of the jet flow reaches about 1.0 m beneath the meniscus. The jetting zone is the high-temperature zone. In the case of two-port SEN and four-port SEN, the flow patterns and distribution of temperature in the central longitudinal section are similar. The jet flow impinges directly on the initially solidified shell and then it is divided into two longitudinal circulations. The heat of molten steel is dissipated along with the longitudinal circulations. The negative segregation band was generated near the bloom surface due to the washing effect by the rotating flow at the solidification front with three nozzle types. The negative segregation deteriorates gradually with the number of ports decreasing.
      PubDate: 2021-03-13
       
  • Phase stability of Fe 23 Zr 6 and thermodynamic reassessment of
           Fe–Zr system
    • Abstract: The stability of the Fe23Zr6 phase in Fe–Zr system was studied, and the partial Fe–Zr phase diagram was revised by means of X-ray diffraction, electron probe microanalysis and differential thermal analysis methods. On the basis of the experimental results in the present work and literature, the Fe–Zr system was reassessed using CALculation of PHAse Diagram (CALPHAD) method. Solution phases, liquid, fcc, bcc and hcp, are modeled as the substitutional solution. The intermetallic compounds, hex.-Fe2Zr, Fe2Zr, FeZr2 and FeZr3 phases, are treated as Fe2(Fe, Zr)1, (Fe, Zr)2(Fe, Zr)1, (Fe, Zr)1Zr2 and (Fe, Zr)1(Fe, Zr)3 by a two-sublattice model, respectively. The Fe23Zr6 phase is treated as stoichiometric compound. A set of self-consistent thermodynamic parameters of the Fe–Zr system was obtained. The results confirm the stability of Fe23Zr6 phase, improve the phase diagram of the Fe–Zr system and provide a theoretical reference for the development of Zr alloys.
      PubDate: 2021-03-12
       
  • Vertical–horizontal coupling nonlinear vibration characteristics of
           rolling mill under mixed lubrication
    • Abstract: Considering the dynamic influence of the roll vibration on the lubricant film thickness in the rolling deformation area, nonlinear dynamic rolling forces related to film thickness in the vertical and horizontal directions were obtained based on the Karman’s balance theory. Based on these dynamic rolling forces and the mechanical vibration of the rolling mill, a vertical–horizontal coupling nonlinear vibration dynamic model was established. The amplitude–frequency equation of the main resonance was derived by using the multiple-scale method. At last, the parameters of the 1780 rolling mill were used for numerical simulation, and the time-domain response curves of the system's vibration displacement and lubricating film thickness under the steady and unsteady conditions were analyzed. The influences of parameters such as interface contact ratio, nonlinear parameters and external disturbances on the primary resonance frequency characteristics were obtained, which provided a theoretical reference for the suppression of rolling mill vibration.
      PubDate: 2021-03-10
       
  • Preparation of calcium ferrite by flue gas desulfurization gypsum
    • Abstract: At present, the continuous accumulation of the flue gas desulfurization (FGD) gypsum in steel plants leads to the serious environmental issues and resource waste. To achieve green and sustainable development for the steel industry, it is significant to improve the usage of by-product gypsum. Employing the sintering FGD gypsum, ferric oxide, and graphite carbon as raw materials, the effects of the carbon content, reaction time, and molar ratio of CaO to Fe2O3 on the desulfurization rate of gypsum were studied based on the orthogonal experiment. The results show that the order of the three influencing factors on the desulfurization rate of FGD gypsum is: molar ratio of CaO to Fe2O3 > reaction time > carbon content. Under the optimal conditions of 20 wt.% carbon content, 4 h reaction time, and 1:1 molar ratio of CaO to Fe2O3, the desulfurization rate of desulfurization gypsum is 95.79%, and 97.57 wt.% of calcium ferrite appears in the solid product, which can be used as sintering additive to increase the economic benefits of enterprises and realize the green ecological development mode of internal generation and internal digestion of solid waste in iron and steel enterprises.
      PubDate: 2021-03-05
       
  • Precipitation behavior of P550 steel for non-magnetic drill collars during
           isothermal aging at 650–900 °C
    • Abstract: Precipitation behavior of P550 steel for non-magnetic drill collars was investigated by microstructure characterization as well as thermodynamic calculation. The results demonstrate that the main precipitate formed at 650–900 °C was cellular Cr2N, and its precipitation depended heavily on the aging temperature. The most sensitive precipitation temperature of cellular Cr2N was 750 °C. At 750 °C, the cellular Cr2N exhibited fast-slow precipitation kinetics with the aging time prolonging. The initial precipitation of cellular Cr2N was governed by the short-range intergranular diffusion of Cr. During long-term aging, its growth was controlled by the long-range bulk diffusion of Cr. In addition, cellular Cr2N induced the precipitation of σ phase ahead of the cell after long period of aging. Increasing the nitrogen content resulted in the increment of both the nucleation site and the driving force for the cellular Cr2N, which jointly promoted its precipitation.
      PubDate: 2021-03-05
       
  • Subgrain microstructures and tensile properties of 316L stainless steel
           manufactured by selective laser melting
    • Abstract: 316L stainless steel samples were manufactured by selective laser melting (SLM). The microstructure of SLM-made 316L stainless steel and the room temperature tensile properties both perpendicular and along the building direction were studied and characterized. The static temperature field during the molten pool formation was simulated by finite element simulation. It indicates that the nonlinear asymmetrical inclined temperature gradient in SLM process produces a large surface tension gradient. The melt forms a Marangoni flow with different convection modes under the action of surface tension as well as a micro-molten pool morphology with subgrain structures such as strip, hexagonal and elongated cellular structures. In addition, there are also epitaxially grown columnar grains. The growth of columnar crystals is not affected by the boundary of the molten pool. Subgrain structures and low-angle grain boundaries make the tensile strength and the elongation of SLM-made 316L sample higher as compared to those of the cast and wrought samples. The room temperature tensile strength of the sample perpendicular to the building direction is higher than that of the sample along the building direction, while the elongation is lower than that of the sample along the building direction.
      PubDate: 2021-03-04
       
  • Kinetic study on co-combustion of pulverized anthracite and bituminite for
           blast furnace injection
    • Abstract: Combustion behavior of single pulverized coals (PCs) and co-combustion characteristics of anthracite (AT) and bituminite (BT) blends with 20 wt.% volatile were studied by thermogravimetric experiments. The results indicated that reaction characteristics of PCs were closely related to their functional group structure and consequently, the pyrolysis of PCs with highly active functional groups initiated at lower temperatures. It was also noticed that the discrepancy of functional group structures between AT and BT might impair their interaction during combustion. The early exhaust of BT at low temperatures would possibly lead to an independent combustion of volatile and residual carbon and eventually the inefficient combustion of their blend. However, the mixing of AT and BT with similar functional group structures was more likely to achieve blends with superior combustion property. Simultaneously, non-isothermal kinetic analysis manifested that the combustion of blends followed random pore model (RPM), and therefore, the parameters calculated by RPM were more accurate to describe their combustion behavior. The kinetic calculation results showed that the activation energy required for decomposition of blends in early combustion stage was much lower owing to the excellent activity of volatile, while residual carbon with stable aromatic hydrocarbon demanded more energy to initiate its combustion.
      PubDate: 2021-03-03
       
  • Effect of W on formation and properties of precipitates in Ni-based
           superalloys
    • Abstract: The formation and properties of precipitates in wrought Ni-based superalloys with different W contents during long-term exposure to high temperatures were investigated. The scanning electron microscope, transmission electron microscope, and chemical phase analysis were used to investigate the formation and properties of precipitates. It is found that with increasing W content, the quantity and thermal stability of MC carbide in Ni-based superalloys increased, while the quantity of M23C6 carbides decreased. As the results show, W has a higher partition coefficient in γ′- and γ-matrix, and the addition of W promotes the precipitation of γ′ phase. W content has no significant effect on the morphology, size, crystal structure, and coarsening rate of γ′ precipitates. The influence of W content on high-temperature tensile and creep properties of the alloys was investigated. The results showed that W content has no obvious influence on the high-temperature yield strength, but the elongation and area reduction decreased significantly when the addition of W was more than 4 wt.%. Because of the similar volume fractions of γ′ phase, the creep fracture strengths in the tested alloys with lower W concentrations were not significantly different after long-term exposure at 700 °C.
      PubDate: 2021-03-03
       
  • Cold compression deformation method for reducing residual stress and
           uniformizing micro-property in ferrite steel
    • Abstract: To reduce internal residual stress and homogenize micro-property of hot-rolled ferrite steel, the cold compression deformation method with small reduction rate has been performed in the hot-rolled samples, and X-ray diffraction and nanoindentation test have been used to detect the residual stress and micro-property. The samples with deformation rate of 0–5.59% or annealing at 550 °C are analyzed. The results show that, due to the coupling effect of thermal expansion and cold contraction and the volume expansion of microstructural transformation from austenite to ferrite, compressive residual stress was found inside the hot-rolled samples. With the increase in cold compression deformation, the dislocation density increased and the microhardness increased gradually, and there is no obvious rule for the change of mean nano-hardness in micro-zone for the center of samples. However, the uniformity of nano-hardness in the micro-zone increased first and then decreased, and the value of residual stress has obvious corresponding relationship with the uniformity of micro-zone property. The cold compression deformation with appropriate reduction rate can reduce residual stress and improve nano-hardness uniformity of the hot-rolled samples, but more deformation (such as reduction rate ε = 5.59%) makes residual stress increase and makes uniformity of nano-hardness deteriorate.
      PubDate: 2021-03-02
       
  • Effects of traditional heat treatment and a novel deep cryogenic treatment
           on microstructure and mechanical properties of low-carbon high-alloy
           martensitic bearing steel
    • Abstract: The effects of traditional heat treatment (quenching and then tempering) and deep cryogenic treatment on the microstructure and mechanical properties of a low-carbon high-alloy martensitic bearing steel were studied by Rockwell hardness test, X-ray diffractometry, scanning electron microscopy and transmission electron microscopy. The results show that the deep cryogenic treatment promotes the transformation of the retained austenite to martensite during cooling, which leads to the hardness of the sample after deep cryogenic treatment higher than that at the quenched state. Also, the carbon content in the martensite matrix after different treatments was calculated and the results indicated that deep cryogenic treatment can promote the segregation of carbon atoms in martensite to dislocations. The segregated carbon atoms act as and grow into nuclei for the formation of fine carbide particles during subsequent tempering. And this resulted in the fact that the hardness of the tempered experimental steel after deep cryogenic treatment is higher than that without deep cryogenic treatment.
      PubDate: 2021-03-01
       
  • Effect of zirconium on inclusions and mechanical properties of China low
           activation martensitic steel
    • Abstract: The effects of 0.01–0.11 wt.% Zr on the inclusions, microstructure, tensile properties, and impact toughness of the China low activation martensitic steel were investigated. Results showed that Zr exhibits good deoxidation and desulfurization abilities. The scanning electron microscope was used to examine the inclusions in the ingots. The main inclusions in the alloys were Zr–Ta–O, Zr–O, and Zr–O–S. However, some blocky Zr-rich inclusions appeared in Zr-2 and Zr-3 alloys. Typical martensitic structures were observed in the alloys, and average prior austenite grain sizes of 21.1, 15.7, and 14.8 µm were obtained for Zr-1, Zr-2, and Zr-3 steels, respectively. However, increasing Zr content of the steels deteriorated their mechanical property, owing to the blocky inclusions. The alloy with 0.01% Zr resulted in excellent mechanical properties due to the fine inclusions and the precipitation of Zr3V3C carbides. Values of 576 and 682 MPa were obtained for the yield strength and ultimate tensile strength of Zr-1 alloy, respectively. Furthermore, the ductile–brittle transition temperature of the alloy decreased to − 85 °C.
      PubDate: 2021-03-01
       
  • Heat transfer characteristics for double-jet in different flow regions on
           a thick plate
    • Abstract: During multi-jet cooling, the complex hydrodynamic characteristics caused by the interaction between jets will affect the heat transfer of the plate. To further clarify the heat transfer characteristics in different flow regions, the double-jet cooling experiments were completed on a 50-mm-thick plate with the initial cooling temperature and jet angle in the range of 300–900 °C and 0°–60°, respectively. The inverse heat conduction was used to calculate the surface temperature and heat flux. Furthermore, the rewetting phenomenon, maximum heat flux and maximum cooling speed were studied. The results show that increasing the angle between jet and wall normal would increase the wetting front’s width downstream of the jet point. When the jet angle was 60°, the maximum value increased by 37.29 mm compared with that when the angle was 0°. The correlation between the width of the wetting front and the radial temperature gradient was further confirmed. In addition, it was found that the maximum heat flux would be affected by the duration of transition boiling, but not affected by complete wetting time. The results clarified the heat transfer mechanisms under various initial cooling temperature and inclination angle conditions on plate cooling in different flow regions, and provided valuable data for controlling heat transfer efficiency and improving cooling uniformity.
      PubDate: 2021-03-01
       
  • Effects of strain rate on austenite stability and mechanical properties in
           a 5Mn steel
    • Abstract: The austenite stability and the mechanical properties in a typical medium Mn grade steel, i.e., 5Mn steel, were investigated under a wide range of strain rates through the combination of experimental and theoretical methodologies. The obtained results indicate that austenite is more stable at a high strain rate, which is due to the suppression of the austenite to martensite transformation. This suppression is attributed to the increased stacking fault energy and the high deformation energy barrier. Moreover, the suppression of martensitic transformation also leads to the decrease in the ultimate tensile strength and the uniform elongation. Owing to the increase in an adiabatic heating temperature, an increase in the uniform elongation is acquired at a high strain rate. The obtained fundamental study results shed light on a wide application of the medium Mn steel under different strain rate conditions.
      PubDate: 2021-02-28
       
  • Numerical simulation of slag layer and its distribution on hot surface of
           copper stave based on ANSYS birth-death element technology
    • Abstract: The core of the long-life copper stave was to ensure the stability of the slag layer, and the uniform distribution of the slag layer was beneficial to restrict the generation of the overthick slag layer. A novel model for calculating the thickness and distribution of the slag layer in the part of copper stave was established based on the finite element theory through the ANSYS birth-death element technology. The distribution and thickness of the slag layer on the hot surface of copper stave were calculated and analyzed when the gas temperature and slag properties tended to be changed, which was applied to characterize the slag-hanging capability of copper stave with the changes of furnace conditions. It was shown that the thickness of hot surface slag layer in the part of copper stave decreased obviously while the temperature of stave body raised rapidly with increasing gas temperature. When the gas temperature was 1400 °C, the inlaid slag layer was gradually melted, and the maximum temperature of the stave body was closed to 120 °C. The change of gas temperature was very sensitive to the adherent dross capability of copper stave which would be enhanced by the promotion of slag-hanging temperature. However, when the slag-hanging temperature was 1150 °C and the gas temperature was lower than 1250 °C, the overthick slag layer was easily formed on the hot surface of the copper stave, and its stability was poor. The improvement in the thermal conductivity of slag could be conducive to the formation of the uniform and stable slag layer on the hot surface of copper stave, especially in the dovetail groove. When the thermal conductivity of the slag was greater than 1.8 W m−2 °C−1, the inlaid slag layer in the dovetail groove was not melted, although the gas temperature reached 1500 °C.
      PubDate: 2021-02-25
       
  • Physical and computational study of a novel submerged entry nozzle design
           for twin-roll casting process
    • Abstract: With significant emphasis on reducing the turbulence in the bath and the need for effective distribution of metal along the roller length in twin-roll casting, a novel submerged entry nozzle (SEN) configuration with two “gap regions” was provided. The “gap regions” of the new SEN divide the bath into two parts, the “upper melt bath” (casting region) and the “lower melt bath” (rolling region). The newly designed SEN was tested by using both full-scale water modeling experiments and numerical simulations. Results demonstrated that the turbulence could only be found near the rotating roller surfaces. The “gap regions” can make the near-wall flows more uniform. They can also prevent the instabilities in the “upper melt bath” to be transferred to the “lower melt bath”, thus improving the stability of the process. Moreover, the novel SEN can stabilize the meniscus where the initial solidification occurs. This is achieved by increasing the SEN immersion depth, which in turn, can enlarge the volume of the upper part of the bath.
      PubDate: 2021-02-24
       
  • Research and application of approximate rectangular section control
           technology in hot strip mills
    • Abstract: Profile requirements of silicon steel strip are extremely high and the thickness difference of cold-rolled products is usually less than 7 μm, and the profile quality of hot-rolled strip is the key to ensure the thickness difference of cold-rolled products. In order to produce the silicon steel strip with high-precision shape, the concept of quasi-rectangular rolling during hot continuous rolling was put forward; the equipment configuration and technical method of approximate rectangular section control were studied. Through the roughing multi-target load distribution technology and the roll configuration technology for uniform wear of a 4-high rolling mill, the strip crown of transfer bar was reduced and the profile control stability was guaranteed. Configuring variable contact back-up roll technology on all stands in the finishing rolling process, equipped with symmetry variable taper work roll and long-stroke intelligent shifting strategy in the downstream stands, and using side rolling lubrication technology can make the roll wear more uniform, reduce the edge drop of silicon steel strip, improve the profile quality, and make the strip section of finishing exit "quasi-rectangular". In addition, induction furnace and side heater were also equipped to guarantee the temperature uniformity of the strip, so as to improve the stability of profile control. The whole control technology is based on the 1580-mm hot continuous rolling production line, designed, and developed according to the characteristics of equipment and products, and has been successfully applied, which can obtain the approximate rectangular strip section satisfying the flatness quality, and improve the strip section precision of silicon steel and other products.
      PubDate: 2021-02-24
       
  • Partitioning of nitrogen atoms and its effect on retained austenite
           content in an ultra-low-carbon Cr–Mn–N stainless steel
    • Abstract: The partitioning of nitrogen atoms and its effect on the retained austenite content (RAC) during quenching and partitioning (Q&P) process were investigated by dilatometry, X-ray diffraction, and field emission transmission electron microscopy with energy-dispersive spectrometer mapping in a 00Cr13Mn8N steel. Nitrogen partitioning by diffusion of N atoms from martensite to austenite occurred at 400 °C after quenching. N atoms are enriched in austenite after partitioning, and the stability of these N-rich austenite is improved and retained at room temperature during subsequent cooling. The different quenching temperatures (QTs) result in different phase fractions after partitioning. With the increase in QT, RAC first increases and then decreases, and the maximum RAC is 28.5 vol.% after quenching at 80 °C. A mathematical model was developed to rapidly and accurately characterize the phase fraction in Q&P process based on the relative length change of the samples partitioned after quenching at different QTs.
      PubDate: 2021-02-24
       
  • Effects of single lance configuration on coal combustion process in tuyere
           from viewpoint of coal plume
    • Abstract: Pulverized coal utilization in the blast furnace is decided by the particle flow and combustion behaviors in the raceway. Under a specific operating condition, these behaviors are directly related to the lance configuration in the upstream tuyere zone. Focusing on single straight lance, six types of single lance configurations were designed by assembling four parameters in different ways. These four parameters are the lance diameter, lance insertion angle, and the horizontal and vertical distances from the lance tip to the tuyere tip. With different lance configuration schemes applied, the pulverized coal combustion process in the lance–blowpipe–tuyere zone was simulated. The simulation results regarding particle diffusion and combustion behaviors were characterized by three indicators from the viewpoint of a coal plume. They are the plume diffusion angle, diffusion uniformity, and the average plume temperature at the tuyere outlet. To promote coal utilization, the values of these indicators under different configurations were analyzed, yielding two optimal configurations. The first one is to reduce the lance length immersed in the blowpipe–tuyere by 100 mm. The other is to increase the horizontal distance from the lance tip to the tuyere outlet by 50 mm, and the insertion angle to 11° with the lance tip located at the tuyere centerline. The findings can enhance the understanding of the influence mechanism of lance configuration on the coal utilization and provide guidelines for the design of new lance configurations.
      PubDate: 2021-02-23
       
  • Longitudinal profiled plate straightening process based on curvature
           integral method
    • Abstract: Considering the variable cross section thickness of longitudinal profiled plate and the dynamic reductions of straightening rolls, an analytical model combining curvature integral method with linear decreasing straightening scheme was proposed to investigate the longitudinal profiled plate straightening process. Moreover, the calculation flow and solution algorithm of longitudinal profiled plate straightening process were presented. To verify the proposed model, calculated straightening forces were compared with the measured values, and very good agreements were achieved. Then, the reduction, contact angle, reverse bending curvature, residual curvature, straightening force and straightening moment of longitudinal profiled plate in the straightening process were calculated and analyzed, and the calculated results show that the curvature integral method can be used to reveal the mechanism of longitudinal profiled plate straightening.
      PubDate: 2021-02-22
       
  • Effect of Ti/V ratio on thermodynamics and kinetics of MC in γ/α
           matrices of Ti–V microalloyed steels
    • Abstract: Through the solubility product theory of the ternary secondary phase, classical nucleation theory, and Ostwald ripening theory, a model was established to describe the thermodynamics and kinetics of (Ti, V)C precipitates in austenite/ferrite (γ/α) matrices. The model was used to calculate the volume fraction, precipitation–temperature–time (PTT) curve, and nucleation rate–temperature (NrT) curve of MC (M = Ti, V) precipitates in γ/α matrices in Ti–V microalloyed steels with various Ti/V ratios, which is verified by hardness tester, transmission electron microscopy and energy-dispersive X-ray spectroscopy. The calculations indicate that, by decreasing Ti/V ratio from Ti4V0 steel to Ti0V4 steel, the complete-dissolution temperature decreases monotonically from 1226 to 830 °C, and the equilibrium volume fraction of MC precipitated from austenite decreases from 0.333% to 0.091% at 900 °C. Moreover, the maximum nucleation temperature of MC precipitated from α matrix decreases from 748 to 605 °C and the fastest precipitation temperature decreases from 844 to 675 °C as Ti/V ratio decreases. PTT and NrT diagrams of MC precipitated from α matrices in different Ti–V microalloyed steels all exhibit C-shaped and inverse C-shaped curves. In addition, both theoretical calculation and experimental results show that when tempered at 600 °C for 100 h, Ti2V2 steel shows the largest hardness value of 312 HV among the three steels tested because it has a larger volume fraction (0.364%), a larger precipitate density (1689 μm−2), and the smallest average size (8.4 nm) of (Ti, V)C precipitates. The theoretical calculations are consistent with experimental results, which indicates that the thermodynamics and kinetics model for (Ti, V)C precipitates is reliable and accurate.
      PubDate: 2021-02-22
       
 
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