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Li X.,Key Laboratory for Ecological Metallurgy of Multimetallic Mineral | Min Y.,Key Laboratory for Ecological Metallurgy of Multimetallic Mineral | Wang B.,Laiwu Steel Group | Jiang M.,Key Laboratory for Ecological Metallurgy of Multimetallic Mineral
Chongqing Daxue Xuebao/Journal of Chongqing University | Year: 2015

The FH40 ship plates containing different Mg, Zr contents are refined with vacuum induction furnace, and the relationship between magnesium and zirconium addition and the decomposition of austenite during continuous cooling rate from 0.1 ℃/s to 30 ℃/s is systematically investigated by a Gleeble-3800 thermal simulator. Continuous cooled microstructure is observed by means of optical microscope. Dilatometric experiments and metallographic observations show that, Mg, Zr and Mg-Zr addition can affect the starting temperatures of the γ-α phase transformation and the pearlite transformation. Mg and Mg-Zr addition suppresses the proeutectoid ferrite transformation and promotes the bainite transformation. The matrix can be dominated as bainite at cooling rate from 5 ℃/s to 30 ℃/s for the Mg-containing steels. It is obviously shown that the addition of zirconium has a significant effect in promoting the nucleation of ferrites. However, the bainite transformation is not well developed, but an evident suppression of the transformation is emerged for the single Zr addition steel. The above studies can provide theoretical foundations for the application of magnesium and zirconium in steel. ©, 2015, Chongqing Medical University. All right reserved. Source


Li M.,Northeastern University China | Li M.,Key Laboratory for Ecological Metallurgy of Multimetallic Mineral | Gao B.,Northeastern University China | Gao B.,Key Laboratory for Ecological Metallurgy of Multimetallic Mineral | And 11 more authors.
Electrochimica Acta | Year: 2015

Abstract The electrochemical behavior of nickel was studied by cyclic voltammetry and chronoamperometry techniques at 353 K using a tungsten electrode in urea-acetamide-LiBr low-temperature molten salt. The cyclic voltammograms indicate that the reduction of Ni(II) to Ni proceeds via a single-step, two-electron transfer process. Chronoamperometric measurements show that the electrodeposition of nickel on the tungsten electrode involves three-dimensional (3D) progressive nucleation under diffusion-controlled growth at 353 K. Nickel coatings were prepared at different cathodic potentials (-0.70 to -0.85 V) and different temperatures (343-373 K) in urea-acetamide-LiBr molten salt. The deposits were characterized by scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD). The SEM images reveal that uniform, dense, and compact deposits were obtained at more positive cathodic potentials within the temperature range of 343-363 K. The EDS and XRD analyses confirm that the obtained deposits are pure nickel. © 2015 Elsevier Ltd. All rights reserved. Source


Zhang W.,Northeastern University China | Zhang W.,Key Laboratory for Ecological Metallurgy of Multimetallic Mineral | Zhang J.H.,Northeastern University China | Zhang J.H.,Key Laboratory for Ecological Metallurgy of Multimetallic Mineral | And 5 more authors.
Ironmaking and Steelmaking | Year: 2014

Non-stoichiometry influences both the thermodynamic and kinetic analyses of the iron oxide redox processes. The thermochemical data of iron oxide redox reactions in various textbooks are not consistent, and the kinetic characteristics are not well understood because of the nonstoichiometry. To clarify such confusions, some famous thermodynamic data are compared, and highly precise experimental work conducted for verification. It is shown that the thermodynamic data for the pure iron oxide reduction reactions from JANAF agree well with the experimental results; the eutectoid temperature of iron oxides was proven to be 576°C; Dieckmann's defect model of magnetite was proven in good agreement with the experimental results only at high oxygen activities but not low oxygen activities; and the dependences of iron deficiency on Δwt-% (weight loss ratio) and Fe2+ % (ferrous ratio) were calculated and experimentally verified in pure iron oxides reduction processes. © 2014 Institute of Materials, Minerals and Mining. Source


Min Y.,Key Laboratory for Ecological Metallurgy of Multimetallic Mineral | Zhong M.,Key Laboratory for Ecological Metallurgy of Multimetallic Mineral | Huang J.,Key Laboratory for Ecological Metallurgy of Multimetallic Mineral | Liu C.,Key Laboratory for Ecological Metallurgy of Multimetallic Mineral | Jiang M.,Key Laboratory for Ecological Metallurgy of Multimetallic Mineral
Steel Research International | Year: 2014

Quenched glass samples of CaO-SiO2-Al2O 3-Na2O-CaF2 system were prepared within the composition of continuous casting mould flux, and the chemical composition and Raman spectra were detected subsequently. The degree of polymerization and structural behavior of Al3+ were investigated on the base of the quantitative calculation of structure species. The experimental data showed that the dominant structure species are Qi (i = 0, 1, 2) of the Si-O tetrahedrons in the liquid mould flux, and the degree of polymerization decreases with the increasement of basicity and the decreasement of Al 2O3 content. Al-O tetrahedrons and Al3+ cations coexist in the liquid mould flux, and the mole fraction of Al-O tetrahedrons increases with the increasement of basicity and Al2O3 content. Under the condition of the mole ratio Al/(Al + Si) < 0.19, the structural behavior of Al3+ is stable in the liquid mould flux. Considering the variation of mould flux composition during Al-killed steel continuous casting process, the initial content of Al2O3 and SiO2 in the mould flux should be controlled appropriately according to the transition point Al/(Al + Si). In the liquid mould flux of CaO-SiO2-Al2O3-Na2O-CaF2 system, Si-O tetrahedrons are the dominant structure species, and the degree of polymerization decreases with the increasement of basicity and the decreasement of Al2O3 content. Al-O tetrahedrons and Al3+ cations coexist in the liquid mould flux, and the mole fraction of Al-O tetrahedrons increases with the increasement of basicity and Al 2O3 content. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source


Li X.L.,Key Laboratory for Ecological Metallurgy of Multimetallic Mineral | Shi P.Y.,Key Laboratory for Ecological Metallurgy of Multimetallic Mineral | Yue Y.Y.,Key Laboratory for Ecological Metallurgy of Multimetallic Mineral | Xie Q.,Key Laboratory for Ecological Metallurgy of Multimetallic Mineral | And 2 more authors.
Applied Mechanics and Materials | Year: 2014

The hydrochloric acid pickling process which is widely applied in carbon steel pickling ensures high speeds with little pollution. In this research, hydrochloric acid pickling process was introduced into stainless steel pickling to improve the surface integrity. Research indicated that the impedance spectrum obtained from 430SS in HCl solution consisted of a capacitive loop at high frequencies and an inductive loop at low frequencies. As the concentration of hydrochloric acid rose, the radiuses of the capacitive loop decreased.And the corrosion potential of 430SS in hydrochloric acid solution moved to positive direction with band to a narrow 0.1V.And high HCl concentration more markedly influenced the charge-transfer resistance. © (2014) Trans Tech Publications, Switzerland. Source

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