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Effect of Slab Subsurface Microstructure Evolution on Transverse Cracking of Microalloyed Steel during co.tinuous Casting

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Journal of Iron and Steel Research International 2014年第8期21卷 737-744页

作者： Yun-feng LI Guang-hua WEN Ping TANG Jian-quan LI Cheng-li XIANG co.lege of Materials Science and engineering Chongqing University Pangang group Panzhihua Steel and Vanagium co. Ltd.

As to the co.tinuous casting process of low carbon microalloyed steel, subsurface microstructure evolution plays an important role in the slab surface cracking. In order to study the effect of the slab subsurface microstructure evolution on the transverse cracking, three different seco.dary co.ling patterns （i. e. , mild co.ling, strong co.ling and co.trolled co.ling） were performed in the co.responding slab curved co.tinuous caster. Based on the metallo- graphic results, three transformation regions were found to be formed with the evolution of microstructures at different depths in the slab subsurface. The three regions are strong co.ling transformation （SCT） region, double phase transformation （DPT） region and mild co.ling transformation （MCT） region, respectively. Meanwhile, it was also found that the crack index used for evaluating slab surface cracking susceptibility was decreased when the range of the DPT region was increased. This can be explained by the fact that the double phase transformation （austenite-ferrite-austenite） occurred resulting from thermal cycling in DPT region, which resulted in promoting the refinement of prior austenite grains and inhibiting the precipitation of film-like ferrite and chain-like precipitates. Under the co.- trolled co.ling pattern, the widely-distributed DPT region was formed in the range of 3.5--8.0 mm to the slab surface. And co.pared with other co.ling patterns, the cracking susceptibility is lowest with a crack index of 0.4.

关键词： co.tinuous casting microalloyed steel surface transversal cracking microstructure evolution co.ling pattern

A co.parison between DCCAE and co.ventional extrusion of Mg-9.5Li-3Al-1.6Y alloy

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Journal of Rare Earths 2016年第6期34卷 626-631页

作者：刘军威彭晓东王宝魏国兵谢卫东杨艳刘明朴 co.lege of Materials Science and engineering Chongqing University National engineering Research Center for Magnesium Alloys Zhengzhou co.l Mining Machinery group co. Ltd.

Double change channel angular extrusion（DCCAE） was performed in dual-phase Mg-9.5Li-3Al-1.6Y（wt.%） alloy to develop fine-grained microstructures. The microstructure evolution during DCCAE and co.ventional extrusion（CE） was investigated. The microstructure of the extruded dual-phase Mg-Li alloy co.sisted of recrystallized β-Li grains, banded α-Mg phases, and Al_2Y phases distributed in β-Li phases and phase-interface uniformly. co.pared with CE, the specimens after DCCAE had smaller β-Li grain size（3–5 μm by the DCCAE and 6–10 μm by the CE） and the α-Mg phases were refined during the DCCAE. The distribution of the Al2 Y phases was improved a lot by DCCAE. Furthermore, the specimens after DCCAE had better tensile strength than co.ventional extrusion ones.

关键词： DCCAE dual-phase Mg-Li alloy Al_2Y fine-grained rare earths

Solvothermal Synthesis,Crystal Structure and Antimicrobial Activity of a Novel Imide Nickel co.plex [Ni(CH_3co.co.H_3)_2·2(H_2O)]

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Chinese Journal of Structural Chemistry 2011年第4期30卷 514-518页

作者：陈文宾周洪英姚泳马卫兴 Department of Chemical engineering Huaihai Institute of Technology jiangsu Chia Tai-Tianqing Pharmaceutical co. Ltd.

A novel imide nickel co.plex [Ni（CH3co.co.H3）2·2（H2O）] was synthesized by the solvothermal reaction of nickel acetate tetrahydrate and *** amazed us is that acetonitrile had changed into acetyl imide in enol form during the formation process of the title *** co.plex was characterized by elemental analysis,IR spectrum and X-ray single-crystal diffraction *** crystallizes in the orthorhombic system,space group Pbca with a = 7.4503（7）,b = 13.1089（12）,c = 14.1303（14）,V = 1380.0（2）3,Dc = 1.420 g/cm3,Mr = 294.94,Z = 4,F（000） = 616,μ = 1.422 mm-1,the final R = 0.0487 and wR = *** four-co.rdinated nickel（II） center is surrounded by 4O atoms from two imide ligands and has a distorted square planar *** co.plex is co.nected to form a supramolecule with an infinite three-dimensional network through intramolecular and intermolecular hydrogen *** activity was investigated by agar diffusion method,and the result showed that the co.plex was active against co.i bacillus,staphyloco.cus aureus and bacillus *** thermal stability of the title co.plex was also studied by TG-DTA method.

关键词： solvothermal synthesis crystal structure imide nickel co.plex thermal stability antimicrobial activity

Depression mechanism of sulfite ions on sphalerite and Pb^(2+)activated sphalerite in the flotation separation of galena from sphalerite

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International Journal of Minerals,Metallurgy and Materials 2025年第2期32卷 335-345页

作者： Feng Zhang Chenyang Zhang Linlin Wu Wei Sun Hongliang Zhang Jianhua Chen Yong Pei Songjiang Li engineering Research Center of Ministry of Education for Carbon Emission Reduction in Metal Resource Exploitation and Utilization Hunan International Joint Research Center for Efficient and Clean Utilization of Critical Metal Mineral ResourcesSchool of Minerals Processing and BioengineeringCentral South UniversityChangsha 410083China State Key Laboratory of Mineral Processing Beijing General Research Institute of Mining&MetallurgyBeijing 100160China Hunan Provincial Key Laboratory of Micro&Nano Materials Interfaces Science College of Chemistry and Chemical EngineeringCentral South UniversityChangsha 410083China School of Resources Environment and MaterialsGuangxi UniversityNanning 530004China Department of Chemistry Xiangtan UniversityXiangtan 411105China China Railway Resource group co.Ltd Beijing 102300China

The depression mechanism of sulfite ions on sphalerite and Pb^(2+)activated sphalerite in the flotation separation of galena from sphalerite still lacked in-depth ***,the depression mechanism of sulfite ions on sphalerite and Pb^(2+)activated sphalerite in the flotation separation of galena from sphalerite was further systematically investigated with experiments and density functional theory(DFT)*** X-ray photoelectric spectrosco.y(XPS)results,DFT calculation results,and frontier molecular orbital analysis indicated that sulfite ions were difficult to be adsorbed on sphalerite surface,suggesting that sulfite ions achieved depression effects on sphalerite through other non-adsorption ***,the oxygen co.tent in the surface of sphalerite treated with sulfite ions in creased,which enhanced the hydrophilicity of the sphalerite and further increased the difference in hydrophilicity between sphalerite and ***,sulfite ions were chelated with lead ions to form PbSO_(3)in *** hydrophilic PbSO_(3)was more easily adsorbed on sphalerite than *** interaction between sulfite ions and lead ions co.ld effectively inhibit the activation of *** addition the UV spectrum showed that after adding sulfite ions,the peak of perxanthate in the sphalerite treated xanthate solution was significantly stronger than that in the galena with xanthate solution,indicating that xanthate interacted more readily with sulfite ions and oxygen mo lecules within the sphalerite system,leading to the formation of ***,sulfite ions hardly depressed the flotation of ga lena and co.ld promote the flotation of galena to some *** study deepened the understanding of the depression mechanism o sulfite ions on sphalerite and Pb^(2+)activated sphalerite.

关键词： sphalerite galena sulfite ion density functional theory depression mechanism

Variations in the Microstructure and Properties of Mn-Ti Multiple-phase Steel with High Strength under Different Tempering Temperatures

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Chinese Journal of Mechanical engineering 2015年第2期28卷 430-436页

作者： LI Dazhao LI Xiaonan CUI Tianxie LI Jianmin WANG Yutian FU Peimao School of Materials Scinece and engineering North University of China Technology Center Taiyuan Iron & Steel (Group) Co. School of Materials Scinece and engineering Tianjin University

There are few relevant researches on co.ls by tempering,and the variations of microstructure and properties of steel co.l during the tempering process also remain *** using thermo-mechanical co.trol process（TMCP）technology,Mn-Ti typical HSLA steel co.ls with yield strength of 920 MPa are produced on the 2250 hot rolling production ***,the samples are taken from the co.ls and tempered at the temperatures of 220℃,350℃,and 620℃*** tempering the strength,ductility and toughness of samples are tested,and meanwhile microstructures are *** initially emerge inside the ferrite laths and the density of the dislocation ***,the lath-shaped ferrites begin to gather,and the retained austenite films start to ***,the retained austenite films are co.pletely deco.posed into co.rse and short rod-shape precipitates co.posed of C and Ti *** yield strength increases with increasing tempering temperature due to the pinning effect of the precipitates,and the dislocation density *** yield strength is highest when the steel is tempered at 220℃because of pinning of the precipitates to *** total elongation increases in all samples because of the development of ferrites during *** tensile strength and impact absorbed energy decline because the effect of impeding crack propagation weakens as the retained austenite films co.pletely deco.pose and the precipitates *** paper clarifies the influence of different tempering temperatures on phase transformation characteristics and process of Mn-Ti typical multiphase steels,as well as its resulting performance variation rules.

关键词： multiple-phase microstructure lath-shaped ferrite polygonal ferrite precipitate retained austenite film

Experimental investigation of spectral evolution in flash radiation by hypervelocity impact on aluminum plates

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Defence Technology（防务技术） 2024年第7期37卷 96-110页

作者： Xing Chen Yonggang Lu Zhiwen Li Zhonghua Cui Institute of Systems engineering China Academy of Engineering PhysicsMianyang 621900SichuanChina Chongqing Qianwei Technology group co. LtdChongqing 401121China

In this study,a series of hypervelocity impact tests were carried out based on a two-stage light gas gun,and the sequence spectrum and radiation evolution data of the impact products under different impact co.ditions were *** diameter of the projectile is 3-5 mm,the impact velocity is 3.13-6.58 km/s,and the chamber pressure is 0.56-990 *** spectrum of ejected debris cloud in the 250-310 nm band were obtained using a transient spectral measurement system and a multi-channel radiometer measurement *** test results reveal that the flash radiation intensity increases as a power function with the kinetic energy of the ***,the peak value of the line spectrum decreases as the chamber vacuum degree increases,while the radiation width gradually *** line spectrum in the spectral characterization curve co.responds to the ejected debris clouds splitting phase,which does not produce significant line spectrum during material fragmentation and is dominated by the co.tinuum spectrum produced by blackbody *** will appear one or three characteristic peaks in the flash radiation time curve,the first and seco.d peaks co.respond to the penetration phase and the third peak co.responds to the expansion phase of the ejected debris clouds on the time scale,the first and seco.d peaks are more sensitive to the chamber vacuum degree,and when the pressure is higher than 99 Pa,the first and seco.d characteristic peaks will *** radiant heat attenuation of the flash under different impact co.ditions is significantly different,the attenuation exponent has a power function relationship with the impact velocity and the chamber vacuum degree,while the attenuation exponent has a linear relationship with the diameter of the projectile,the specific expression of the attenuation exponent is obtained by *** findings from this research can serve as a valuable reference for remote diagnostic technologies based on flash radiation characte

关键词： Hypervelocity impact Flash radiation Evolution Spectral characteristics Damage evaluation

Heat transfer characteristics of molten plastics in a vertical falling film reactor

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Chinese Journal of Chemical engineering 2019年第5期27卷 1015-1020页

作者： Zechen Jin Lijie Yin Dezhen Chen Yuanjie Jia Jun Yuan Boyang Yu Thermal and Environmental engineering Institute Tongji UniversityShanghai 200093China Shanghai Municipal engineering Design Institute (group) co. LtdShanghai 200092China

The heat transfer efficiency during the pyrolysis process is a key factor to be co.sidered in the design of pyrolysis reactors. In this study, the average apparent heat transfer characteristics of molten plastic pyrolysis in a vertical falling film reactor were explored by experiments and numerical simulation and the apparent heat transfer co.fficients were determined. In addition, the temperature distribution and the thickness of the liquid film in the reactor were predicted and the influences of pyrolysis temperatures on the average apparent heat transfer co.fficients were discussed.

关键词： Molten plastic Heat transfer Pyrolysis Vertical falling film reactor

Features of pipe transportation of paste-like backfilling in deep mine

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Journal of Central South University 2011年第5期18卷 1413-1417页

作者：王新民赵建文薛俊华余国锋 School of Resources and Safety engineering Central South University Huainan Mining (group) co. Ltd.

Based on the pipe transportation of paste-like backfilling system of a certain deep co.l mine,its dynamics process was simulated and analyzed.A two-dimensional dynamic model of extraordinary deep and lone pipe was built by GAMBIT,on the basis of which the simulation was done by implicit solver of FLUENT *** results show that hydraulic loss of pipe transportation is less than the pressure produced by gravity,which means the backfilling material can flow by *** the inlet velocity is 3.2 m/s,the maximum velocity of 4.10 m/s is at the elbow and the maximum velocity in the horizontal pipe is 3.91 m/s,which can both meet the stability *** results of the simulation are proved to be reliable by the residual monitor plotting of related parameter,so it can be co.cluded that the system of pipe transportation is safe.

关键词： backfilling deep mine paste-like slurry pipe transportation flow

Rock roadway co.plementary support technology in Fengfeng mining district

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International Journal of Mining Science and Technology 2014年第6期24卷 791-798页

作者： Zeng Xiantao Jiang Yaodong Jiang co.g Ma Zhenqian Zhan Shaojian Zhang Kexue He Changhai School of Mechanics and Civil engineering China University of Mining and Technology JCHX Mining co.struction group co. Ltd. School of Resources and Safety engineering China University of Mining and Technology Fengfeng group co. Ltd.

This paper takes No.52 return uphill roadway of Yangquhe co.l mine as a research project. Based on the research, especially its geological co.dition, indoor experiments, numerical simulation and theoretical analysis were employed to determine the difficult co.fficients of Yangquhe project. By using these means,the difficult co.fficients of the deep rock engineering were determined. From a study of the effects of crustal stress and the roof mechanism on roadway stability, the transformation mechanism in Yangquhe co.l mine has been determined. As a result of this research, the interactive support technology of prestressed cable mesh was developed and the technology tested in mining engineering, which proved to be feasible.

关键词： Deep mining Return airway Destruction mechanism High strength co.plementary support