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Determination of liquidus temperatures in high-alloyed Fe-C-Mn-Si- Al steels using differential thermal analysis

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Journal of Iron and Steel Research International 2018年第5期25卷 546-553页

作者： Chang-ling Zhuang jian-hua liu College of Materials and Metallurgy Guizhou UniversityGuiyang 550025 Guizhou China Engineering Research Institute University of Science andTechnology Beijing Beijing 100083 China

The liquidus temperature of the Fe-C-Mn-Si-Al alloy was investigated by using an improved differential thermal analysis method, which effectively tackles down the manganese evaporation in the course of differential thermal analysis experiments for high-manganese twinning-induced plasticity （TWIP） steels at high temperature. It was found that the liquidus temperature is more strongly dependent on the silicon content than expected. By considering the high manganese content in the Fe-C-Mn-Si-Al TWIP steels, the effect of carbon content on the depression coefficient of manganese should not be ignored, which has considerable impact on the liquidus temperature. An equation was summarized to effectively predict the liquidus temperature for a wide range of high-manganese steels. Meanwhile, the prediction results of the equation are consistent with the experimental results, as well as those results acquired from ThermoCalc.

关键词： TWIP steel Thermal analysis Liquidus temperature High-manganese steel

Effects of Particle Size on Nitridation Kinetics of Manganese Powder

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Journal of Iron and Steel Research International 2015年第6期22卷 543-550页

作者： Ting LUO jian-hua liu Hong-bo liu jian liu Research Institute of Metallurgy Engineering University of Science and Technology Beijing

Isothermal thermo-gravimetric analysis was applied to investigate the nitridation kinetics of manganese powder with different particle sizes at 800, 900 and 1000 ℃. The apparent activation energy and nitridation kinetics equations of manganese powder with different particle sizes were obtained from unreacted shrinking core model and Arrhenius formula. It was found that the nitridation mechanism was controlied by interracial chemical reaction. The apparent activation energy and the apparent rate constant of nitridation reaction were affected by particle sizes. With the decrease of particle size, the apparent activation energy decreased whilst the apparent rate constant increased. It was suggested that the refinement of the manganese powder contributed to the increase of molar surface energy, which accounted for the lower apparent activation energy.

关键词： manganese powder nitridation isothermal thermo-gravimetric analysis apparent activation energy kinetics

Carbothermal reduction characteristics of oxidized Mn ore through conventional heating and microwave heating

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International Journal of Minerals,Metallurgy and Materials 2021年第2期28卷 221-230页

作者： Yang He jian liu jian-hua liu Chun-lin Chen Chang-lin Zhuang Institute of Engineering Technology University of Science and Technology BeijingBeijing 100083China Commonwealth Scientific and Industrial Research Organisation Melbourne 3168Australia Dongbei Special Steel Group Co. Ltd.Dalian 116105China College of Materials and Metallurgy Guizhou UniversityGuiyang 550025China

For the purpose of exploring a potential process to produce FeMn,the effects of microwave heating on the carbothermal reduction characteristics of oxidized Mn ore was *** microwave heating curve of the mixture of oxidized Mn ore and coke was analyzed in association with the characterization of dielectric *** comparative experiments were conducted on the carbothermal reductions through conventional and microwave heatings at temperatures ranging from 973 to 1373 *** thermogravimetric analysis showed that carbothermal reactions under microwave heating proceeded to a greater extent and at a faster pace compared with those under conventional *** metal phases were observed in the microstructures only under microwave *** carbothermal reduction process under microwave heating was *** electric and magnetic susceptibility differences were introduced into the thermodynamics analysis for the formation of metal *** developed thermodynamics considered that microwave heating could make the reduction of MnO to Mn more accessible and increase the reduction extent.

关键词： carbothermal reduction manganese ore manganese oxides microwave heating thermodynamics electromagnetic fields

Preparation and characterization of in-site regenerated TiO_2-ACFs photocatalyst

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International Journal of Minerals,Metallurgy and Materials 2011年第3期18卷 357-363页

作者： Rong Yang jian-hua liu Song-mei Li Engineering Design ＆ Research Institute of the Second Artillery Corps Beijing 100011 China School of Materials Science and Engineering Beihang University Beijing 100083 China

In-site regenerated titanium dioxide-activated carbon fibers （TiO2-ACFs） photocatalyst was prepared by the sol-gel method. De-tailed surface and structural characterization of the TiO2-ACFs photocatalyst was carried out. The photoactivity of TiO2-ACFs under ultra-violet irradiation was compared with original ACFs and pure TiO2 by the degradation of methylene blue aqueous solution. The degradation efficiency by the TiO2 （5wt%）-ACFs sample is much higher than that by TiO2 and ACFs. The results show that the photocatalysis by TiO2-ACFs is a six-step process. The adsorption-transfer-photocatalysis rate of TiO2-ACFs is higher than the adsorption-photocatalysis rate of TiO2, so the photocatalysis rate of the TiO2-ACFs system is higher than that of TiO2 photocatalyst.

关键词： photocatalysts photocatalysis microstructure titanium dioxide activated carbon fibers

Inclusion variations and calcium treatment optimization in pipeline steel production

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International Journal of Minerals,Metallurgy and Materials 2011年第5期18卷 527-534页

作者： jian-hua liu hua-jie Wu Yan-ping Bao Min Wang Research Institute of Metallurgy Engineering University of Science and Technology Beijing Beijing 100083 China School of Metallurgical and Ecological Engineering University of Science and Technology Beijing Beijing 100083 China

SiCa line and SiCaBaFe alloy were injected into liquid pipeline steel at the end of LF refining as calcium treatment,and samples were taken from the ladles,mould,and *** of Ca content and inclusions shows that Ca content in steel decreases obviously in the following process after calcium treatment;the compositions,morphology,and sizes of inclusions also vary much in the production;primary inclusions in the ladles prior to calcium treatment are mainly Al2O3 inclusions,but they turn to fine irregular CaS-CaO-Al2O3 compound inclusions after the treatment,then become fine globular CaO-Al2O3 inclusions in the mould,and finally change to a few larger irregular CaS-CaO-Al2O3 complex inclusions in the *** study reveals that inclusion variations are related with the preferential reactions among Ca,Al2O3,and S and the precipitation of S in CaO-Al2O3 inclusions with high sulfur *** evaluation standards for calcium treatment in high-grade pipeline steel were put forward according to the inclusion variations and requirements of pipeline steel on inclusion controlling,and the calcium process was studied and optimized.

关键词： pipeline steel refining inclusions calcium treatment thermodynamics precipitation

Surface reaction of Bacillus cereus biomass and its biosorption for lead and copper ions

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Journal of Environmental Sciences 2007年第4期19卷 403-408页

作者： PAN jian-hua liu Rui-xia TANG Hong-xiao State Key Laboratory of Environmental Aquatic Chemistry Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Beijing 100085 China.

In this study, the surface chemical functional groups of Bacillus cereus biomass were identified by Fourier transform infrared （FTIR） analytical technique. It had been shown that the B. cereus cells mainly contained carboxyl, hydroxyl, phosphate, amino and amide functional groups. The potentiometric titration was conducted to explain the surface acid-base properties of aqueous B. cereus biomass. The computer program FITEQL 4.0 was used to perform the model calculations. The optimization results indicated that three sitesthree pKas model, which assumed the cell surface to have three distinct types of surface organic functional groups based on the IR analysis results, simulated the experimental results very well. Moreover, batch adsorption experiments were performed to investigate biosorption behavior of Cu（Ⅱ） and Pb（Ⅱ） ions onto the biomass. Obviously, the adsorption equilibrium data for the two ions were reasonably described by typical Langmuir isotherm.

关键词： Bacillus cereus biosorption Fourier transform infrared (FTIR) acid-base characteristic heavy metals

Determination of the liquidus and solidus temperatures of FeCrAl stainless steel

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International Journal of Minerals,Metallurgy and Materials 2015年第11期22卷 1141-1148页

作者： Zhi-biao Han jian-hua liu Yang He Kang-wei Li Yi-long Ji jian liu Research Institute of Metallurgy Engineering University of Science and Technology Beijing

The liquidus and solidus temperatures of FeCrAl stainless steel were determined by differential scanning calorimetry（DSC） at different heating rates. They were also calculated by Thermo-calc software and empirical formulae separately. The accuracy of calculation results was assessed by comparison with the corresponding DSC results. The liquidus temperatures calculated by empirical formulae, which exhibited a maximum deviation of 8.6℃ were more accurate than those calculated using Thermo-calc, which exhibited a maximum deviation of 12.11℃. On the basis of Thermo-calc calculations performed under the Scheil model, the solidus temperature could be well determined from solid fraction（fS） vs. temperature（t） curves at fS = 0.99. Furthermore, a theoretical analysis to determine the solidus temperature with this method was also provided.

关键词： ferritic stainless steel liquidus temperature solidus temperature differential scanning calorimetry

Effect of the microstructure of Al 7050-T7451 on anodic oxide formation in sulfuric acid

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International Journal of Minerals,Metallurgy and Materials 2009年第4期16卷 432-438页

作者： jian-hua liu Ming Li Song-mei Li Min huang School of Materials Science and Engineering Beihang University Beijing 100083 China

The effect of the microstructure of an Al 7050-T7451 substrate on the anodic oxide formation in sulfuric acid was studied in this article. The microstructure of the substrate was assessed by optical microscope （OM） and transmission electron microscope （TEM）. The surface and cross-section morphologies of the oxide films were examined by scanning electron microscope （SEM）. The chemical composition of intermetallic particles in the alloys and films was investigated using energy dispersive spectroscope （EDS）. The roles of intermetallic phases and grain or subgrain boundaries on the oxide film formation were researched using the potentiodynamic and potentiostatic polarization technique in sulfuric acid solution. The results show that the transition of coarse intermetallic particles or grain （subgrain） boundaries at the surface of Al alloys can be characterized by potentiodynamic polarization curves. The surface and cross-section micrographs of the anodic layer seem to preserve the microstructure of the substrate. Large cavities in the anodic films are caused by the preferential dissolution of coarse AItCuMg particles and the entrance of Cu-rich remnants into the electrolyte during anodizing. The Al7Cu2Fe particles tend to be occluded in the oxide layer or lose from the oxide surface because of peripheral trenching. Small pores in the films are induced by the dissolution of precipitates in grain or subgrain boundaries. The film surface of recrystallized grain bodies is smooth and homogeneous.

关键词： aluminum alloys anodic oxide intermetallic particles grain boundaries

Influence of Rust Layers on the Corrosion Behavior of Ultra-High Strength Steel 300M Subjected to Wet–Dry cyclic Environment with Chloride and Low Humidity

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Acta Metallurgica Sinica(English Letters) 2015年第2期28卷 139-146页

作者： Qiang Guo jian-hua liu Mei Yu Song-Mei Li Key Laboratory of Aerospace Materials and Performance(Ministry of Education) School of Materials Science and Engineering Beihang University

The influence of rust layers on the corrosion behavior of ultra-high strength steel 300M subjected to a simulated coastal atmosphere was investigated by corrosion weight loss, surface analysis techniques, and electrochemical methods. The results exhibit the presence of a large proportion of γ-FeOOH and α-FeOOH and a small amount of Fe3O4 in the outer rust layer. During the wet-dry cyclic process, the bonding performance and the density of outer rust layer deteriorate with the thickness of outer rust. The inner rust layer plays a main role on protectiveness, which can be attributed to the formation of an ultra-dense and adherent rust film with major constituent of α-FeOOH and α-Fe2O3 on the steel.

关键词： Ultra-high strength steel Wet-dry Chloride Corrosion Rust