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Yao D.,State Key Laboratory of Advanced Metallurgy | Yao D.,University of Science and Technology Beijing | Li J.,State Key Laboratory of Advanced Metallurgy | Li J.,University of Science and Technology Beijing | Li J.,Yangjiang Shibazi Group
Jinshu Rechuli/Heat Treatment of Metals

Microstructure, carbides and mechanical properties of 7Cr17MoV stainless steel used as cutlery material produced by hot rolling and cold rolling were studied. The experimental results demonstrate that the microstructure of the rolled steel consists of spheroidal pearlite and carbides. During hot rolling process, the carbides will aggregate obviously and the size of carbides is almost above 2 μm. Then after cold rolling, the aggregation of carbides disappear, and the carbides become fine and uniformly distributed, at the same time, there are some nanoscale carbides. During cold rolling process, the vanadium carbides and molybdenum carbides will decrease and disappear and the carbides mainly consist of (Fe, Cr)23C6. Tensile strength of the cold rolled thin strip (0.7 mm) is about 690 MPa. The dimples and the second phase particles can be easily seen in the tensile fracture, and the second phase particles are identified to be mainly carbides and inclusions. Source

Zhi X.,University of Science and Technology Beijing | Guo Z.C.,State Key Laboratory of Advanced Metallurgy
Applied Mechanics and Materials

This research through the study on the properties of silicon dust, put forward in combination with lime kiln tail gas recycling carbon dioxide, preparation of precipitated silica (Nano White Carbon Black) of high value utilization technology, and studied and summarized process of the dissolution and precipitation by carbon dioxide. The silica fume is in amorphous form, and it has some special powder properties such as ultra fine grain size and high specific surface area and high chemical activity, these provide favorable foundation for low energy consumption process of recycling the powder. In the dissolution stage, the optimization reaction time is about 40 minutes, this time to complete the process of the reaction more than 90%. And the reaction is the fastest in the first 20 minutes, complete response 75% of the reaction. In the stage of carbonization, with increase of the concentration of the precursor, the particle diameter becomes larger, but the specific surface area of the powder will reduce, the porosity and the surface activity of it will reduce corresponding. © (2013) Trans Tech Publications, Switzerland. Source

Zuo Q.-W.,Beijing University of Technology | Zuo Q.-W.,State Key Laboratory of Advanced Metallurgy | Cang D.-Q.,Beijing University of Technology | Cang D.-Q.,State Key Laboratory of Advanced Metallurgy | An X.,Tangshan Iron and Steel Co.
Open Fuels and Energy Science Journal

The combustion characteristics of pulverized coal when using blast furnace slag charged with iron ore containing rare earth elements as a composite catalyst were investigated by thermo gravimetric analysis. The results show that the combustion char acteristics of pulverized coal loaded with 21.3% by weight of blast furnace slag containing 15% rare earth ore are better than those of others. It is also indicated that the composite catalyst promotes combustion of volatiles and also performs well for carbon residue. The mechanism of promotion by the composite catalyst was explored. The kinetic parameters calculated by the Coats-Redfern model show that the activation energy(E) was reduced by10 kJ/mol, the time of combustion was shortened by 3min, pre-exponential factor(A) reached 2.7×104/min and general combustion characteristic index (S)was 1.09. © Zuo et al.; Licensee Bentham Open. Source

Shan K.,State Key Laboratory of Advanced Metallurgy | Shan K.,University of Science and Technology Beijing | Guo X.-M.,State Key Laboratory of Advanced Metallurgy | Guo X.-M.,University of Science and Technology Beijing
Materials Letters

A single phase perovskite, YxSr1-xTi 0.6Fe0.4O3-δ (x=0.07, 0.08, 0.09), was synthesized at 1350 C by the sol-gel method. The effects of Y-doping on the electronic and ionic conductivities of YxSr1-xTi 0.6Fe0.4O3-δ were investigated. The ionic conductivity of SrTiO3-based materials can be significantly improved by Y-doping on the A-site and Fe-doping on the B-site. We report in this paper a remarkable enhancement of ionic conductivity of Y, Fe co-doped SrTiO 3 by the increase in Y-doping amount on the A-site. The total electrical conductivity and ionic conductivity were 0.135 S/cm and 0.017 S/cm for Y0.07Sr0.93Ti0.6Fe0.4O 3-δ at 800 C, respectively, while were 0.056 S/cm and 0.02 S/cm for Y0.09Sr0.91Ti0.6Fe0.4O 3-δ. © 2014 Elsevier B.V. Source

Li Y.-L.,University of Science and Technology Beijing | Li Y.-L.,Beijing Key Laboratory of Green Recycling and Extraction of Metal GREM | Li Y.-L.,State Key Laboratory of Advanced Metallurgy | Cheng S.-S.,University of Science and Technology Beijing | And 2 more authors.
Kang T'ieh/Iron and Steel

The mathematical models of blast furnace (BF) hearth were established and the masonry structures of large carbon blocks and small carbon bricks for hearth were discussed from the view of heat transfer. The temperature of these two hearth structures during BF drying process were calculated as well as after blow-in. It is found that the filling between staves and carbon bricks can not be dried effectively at present BF drying conditions and the thermal conductivity of filling can not reach the designed value. Moreover, with the existing of filling, the hot face temperature of lining is higher which results in more serious erosion. Therefore, the filling should be cancelled between staves and carbon bricks. It has obvious advantage of heat transfer for carbon bricks touching with staves directly. The hearth structure of small carbon bricks could be designed to touch with staves directly so that it exterminates the barriers on heat transfer of hearth. The hearth structure of large carbon blocks should be put some small carbon bricks touch with staves directly and then make the filling between the small carbon bricks and large carbon blocks. The filling moves towards center of BF more than about 200 mm. In order to dry filling completely during BF drying process, the necessary method is without utilizing cooling water. Meanwhile, some measures are discussed for keep staves safe. Source

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