Effects of rare earth on inclusions and corrosion resistance of 10PCuRE weathering steel

The types,morphologies and distributions of nonmetallic inclusions in Cu-P weathering steels with and without rare earth were analyzed through a quantitative image analyzer,scanning electron microscopy(SEM)and energy dispersive spectroscopy(EDS)attached to SEM.Solid-soluble content of rare earth in the steels was analyzed by non-aqua electroanalysis and ICP.The results showed that rare earth modified the types and the morphologies of inclusions in the weathering steels.The small spherical rare earth oxysulfides and rare earth sulphides replaced the elongated MnS inclusions in the RE weathering steels.The rare earth inclusions dispersedly distributed and most inclusions were smaller than 2 μm in size.The optimum content of RE was 0.0065%-0.016% for 10PCuRE weathering steels containing about0.002% oxygen and 0.004% sulfur.Solid-soluble content of rare earth in steels was(14-20)x 10-6,which can act as a micro-alloying element.The corrosion resistance of 10PCuRE weathering steels and Q235 were studied by dry-wet cyclic immersion test.Their corrosion rates were obtained respectively.The polarization curves and pitting corrosion behaviors of weathering steels with and without rare earth were measured by electrochemical methods.The corrosion resistance of Cu-P weathering steels was improved by adding an appropriate amount of rare earth.Less and fewer rare earth inclusions largely decreased pitting susceptibility and rate of pit propagation.The pitting potential and the resistance against pitting corrosion of the RE weathering steel were significantly improved due to the modification of rare earth to inclusions.     

Lanthanide NIR luminescence for telecommunications, bioanalyses and solar energy conversion

Present-day advanced technologies heavily rely on the exciting magnetic and spectroscopic properties of lanthanide ions. In particular, their ability to generate well-characterized and intense near-infrared (NIR) luminescence is exploited in any modern fiber-optic telecommunication network. In this feature article, we first summarize the whereabouts underlying the design of highly luminescent NIR molecular edifices and materials. We then focus on describing the main trends in three applications related to this spectral range: telecommunications, biosciences, and solar energy conversion. In telecommunications, efforts concentrate presently on getting easily processable polymer-based waveguide amplifiers. Upconversion nanophosphors emitting in the visible after NIR excitation are now ubiquitous in many bioanalyses while their application to bio-imaging is still in its early stages; however, highly sensitive NIR-NIR systems start to be at hand for both in vitro and in vivo imaging, as well as dual probes combining magnetic resonance and optical imaging. Finally, both silicon-based and dye-sensitized solar cells benefit from the downconversion and upconversion capabilities of lanthanide ions to harvest UV and NIR solar light and to boost the overall quantum efficiency of these next-generation devices.     

Evaluation of D113 cation exchange resin for the removal of Eu(Ⅲ) from aqueous solution

Batch adsorption experiments were conducted for the adsorption of Eu(Ⅲ) ions from aqueous solution by D113 resin. The results indicated that D113 resin could adsorb Eu(Ⅲ) ion effectively from aqueous solution. The adsorption was strongly dependent on pH of the medium with enhanced adsorption as the pH turned from 3.50 to 7.00 and the optimal adsorption condition was in HAc-NaAc medium with pH value of 6.50. The maximum uptake capacity of Eu(Ⅲ) ions was 290.9 mg/g D113 at 298 K, at an initial pH value of 6.50. The overall adsorption process was best described by Lagergren-first-order kinetics. When Freundlich and Langmuir isotherms were tested, the latter had a better fit with the experimental data. The thermodynamic parameters such as free energy (G) which were all negative, indicated that the adsorption of Eu(Ⅲ) ions onto D113 resin was spontaneous and the positive value of enthalpy (H) showed that the adsorption was endothermic in nature. Thomas model was applied to experimental column data to determine the characteristic parameters of column useful for process design. Furthermore, Eu(Ⅲ) could be eluted by using 3.0 mol/L HCl solution and the D113 resin could be regenerated and reused.     

Phase structure and temperature dependent luminescence properties of Sr2LiSiO4F: Eu2+ and Sr2MgSi2O7: Eu2+ phosphors

Green-emitting Sr2LiSiO4F:Eu2+ and blue-emitting Sr2MgSi2O7:Eu2+ phosphors were synthesized by the conventional high temperature solid-state route,respectively.Their structures and photoluminescenee properties were comparatively investigated.It was found that the mixture phases of Sr2MgSi2O7 and SrF2 were obtained when a part of Sr2+ in Sr2LiSiO4F was replaced by some amount of Mg2+ in order to design the possible SrMgLiSiO4F:Eu2+ phosphor.Based on the photoluminescence analysis,Sr2LiSiO4F:Eu2+ phosphor exhibited a green broad emission band of main peak at 513 nm under the excitation of 365 nm,while the Sr2MgSi2O7:Eu2+ and SrMgLiSiO4F:Eu2+ phosphor showed blue emission centered at 467 nm.The temperature dependent photoluminescence properties and room temperature decay time for the three kinds of phosphors were also discussed in this paper.     

Er3+-substituted W-type barium ferrite: preparation and electromagnetic properties

Er3+-substituted W-type barium ferrites Ba1-xErx(Zn0.3Co0.7)2Fe16O27(x=0.00,0.05,0.10,0.15,0.20)were synthesized by polymer adsorbent combustion method.Samples were characterized by X-ray diffraction analysis(XRD),X-ray fluorescence(XRF),scanning electron microscopy(SEM)and network analyzer to investigate the relationships among Er3+concentration,crystal structure,surface mcrphology and electromagnetic properties.All the XRD patterns showed pure phase of W-type barium ferrite when x≤0.15,while the impurity phase of ErFeO3 appeared when x=0.20.The pure W-type barium ferrite showed a hexagonal flake shape.In addition,the microwave electromagnetic properties of samples were analyzed in the frequency range of 2-18 GHz.It was indicated that the electromagnetic properties were significantly improved when Er3+doping content was 0.10.The reasons were also discussed using electromagnetic theory.The optimized ferrite exhibited excellent microwave absoption performance.The maximum of reflection loss(RL)reached about-27.4 dB and RL was below-10dB at the frequency range from 8.4 GHz to 18 GHz,when the thickness was 2.6 mm.     

EXAFS investigation and luminescent properties of nanosized Tb: Lu2O3 phosphors

Nanosized terbium doped Lu2O3 phosphors were synthesized via a modified co-precipitation processing.The as-prepared Tb:Lu2O3 phosphors was consisted of well crystallized nanosized sphere particles with a diameter of about 30 nnx Local structure of Tb ions in Lu2O3 lattice was investigated by an analytical approach based on Fourier transformation of the extended X-ray absorption fine structure(EXAFS) data.X-ray near edge structure (XANES) spectra suggested that all Tb ions doped were tervalonce.EXAFS results indicated that Tb ions have entered the Lu2O3 cubic lattice by means of solid solution.The coordination number and first shell Tb-O distance dropped with the increasing of Tb concentration.Emission spectra of the phosphors was shown to be typical for Tb3+ with main components at 542,550 and 490 nm,derived from irradiative relaxation of 5D4 level.The emission intensity decreased severely with the increasing of Tb concentration from 1 mol.% to 15 tool.%,suggesting a significant concentration quenching above 1 mol.% Tb.The reduction of emission intensity was interpreted by higher distortion derived relaxation among the surface state resident Tb3+ ions.     

Multi-Pass Simulation of Heavy Plate Rolling Including Intermediate Forced Cooling

Thermomechanical Controlled Processing (TMCP) including accelerated cooling after the final hot rolling pass is a well-established technology,widely applied in HSLA steel plate production.However,there are still certain limitations,especially for thicker plate.The rolling schedule includes a long holding period (HP) after the roughing stage to allow the temperature to fall sufficiently for optimised TMCP during finishing.Intermediate Forced Cooling (IFC) applied during the HP can increase productivity by decreasing the required hold time,can restrict austenite grain growth,and can also improve the subsequent strain penetration in thick plate with further metallurgical benefits.Multi-pass plane strain compression (PSC) tests have been performed on the thermomechanical compression (TMC) machine at Sheffield University including different severities of IFC.Clearly it is impossible to simulate all aspects of the temperature and strain gradients present in thick plates in laboratory specimens,and most of the tests were conducted at temperatures and strains calculated by Finite Element modelling as relevant to specific positions through the plate thickness.However,some aspects of the gradients were addressed with tests using cold platens.The results have indeed shown that IFC can shorten the HP and reduce austenite grain growth and its variation across thick plate.     

Overview of Particles and Bubbles in Continuously Cast Steel

This paper gives an overview of phenomena associated with particles and bubbles in continuously cast steel. During steel processing from deoxidation to solidification the inclusion population undergoes changes with opportunities of removal. Flotation is an important separation mechanism. Inclusion particles may accumulate in the solidifying strand, thus forming enriched bands, which depend on the type of casting machine. Bubbles are created during inert gas injection. They also change in size, can float out, but also form accumulation bands. The interaction of bubbles and particles is discussed. Internal structure that recently has been observed on the inner surface of bubbles will be reviewed.     

烦恼 快乐 艺术——池莉“人生三部曲”解读

池莉的"人生三部曲"--<烦恼人生>、<不谈爱情>、<太阳出世>诉尽了普普通通的市民烦恼,小说中主人公被柴米油盐、吃喝拉撒、老婆孩子等琐事所烦着,从而构成他们的"烦恼人生".然而池莉通过自己的艺术创作,以积极的人生态度,又让读者体会到生活本身的快乐,"烦恼人生"中包含着"快乐人生".     

属性块在工程图形中的研究与应用

介绍了在工程图形中用属性块标注表面粗糙度的方法.采用属性块不仅能避免大量重复性的工作,还能节省大量的存储空间,具有提高绘图速度、质量,便于修改,资源共享等应用价值.     

顶燃式热风炉热风管道长寿设计浅谈

对顶燃式热风炉热风管道的破损机理进行了分析,就热风管道补偿的设计,管道砖衬结构的设计和耐材种类的选择提出了一些看法,并对热风管道砌筑和烘烤提出了一些建议,以确保热风管道安全使用及长寿。     

2500m~3高炉热风炉生产准备实践

炼铁分公司高炉分厂2500m3高炉热风炉是八钢第一次采用硅质耐材的顶燃式热风炉,因此在耐材砌筑、烘炉及热风炉保温至高炉开炉阶段采取了相应的技术措施,使热风炉目前工作状况良好,送风温度1 200℃,炉皮没有出现发红及开裂现象,满足高炉高风温的需求。     

马钢2500 m3高炉热风短管功能恢复

马钢2500m^3高炉投产后不到2年，4座热风炉的热风短管及波纹管相继损坏，使高炉投产6年多风温难以达标。2000年5月至7月，在高炉正常生产的情况下，成功地更换了2号、3号、4号热风护的热风短管及波纹管，高炉风温很快就超过了设计水平。     

湘钢 750 m3 高炉热风炉故障原因及解决办法

湘钢750m^3高炉3座热风炉先后存在炉壳表面温度偏高，开裂，热风短管的波纹管膨胀变形并导致热风主管移位等问题，经过采取对3座热风炉分段灌浆及对变形波纹管进行换型，并对热风炉与热风主管之间增加拉紧装置等措施后，热风炉系列故障基本解决，大大降低了休风率，提高了风温，保证了高炉生产顺利。     

梅山高风温长寿命内燃式热风炉的设计与生产实践

简要回顾了梅山内燃式热风炉的历史和现状,分析了梅山2号高炉配置的高风温长寿内燃式热风炉采用的新技术及初步效果。认为强化燃烧能力、提高热流强度、缩短送风时间、发挥预热助燃空气和煤气的作用、回收废气热量、提高总热效率、加强操作技术管理是热风炉高风温长寿的有效手段。     

热管换热器用于高炉热风炉余热回收

热管换热器是一种新型的高效换热装置。本文介绍了热管换热器在高炉热风炉余热回收中的应用，运行实践表明效果良好，可在我国冶金系统中推广，以提高高炉热风炉的热效率。     

南钢3号高炉高风温技术的应用

南钢公司认真消化球式热风炉等新技术,改进控制工作,使送风系统连续正常运行至今,实现了高风温,取得良好效果.     

鞍钢7号高炉热风炉烘炉实践

对鞍钢7号高炉热风炉烘炉设备及烘炉操作经验进行了总结。由于烘炉前准备工作充分、烘炉曲线制定合．理,热风炉运行情况良好,为硅砖热风炉烘炉提供了重要的参考价值。     

高风温长寿热风炉的设计

介绍了不同形式热风炉的特点和结构稳定性,针对鞍钢4号高炉增建4号热风炉采用的新技术－近似悬链线拱顶、烟气分配、冷风分配、圆形火井、板块结构、滑动缝、膨胀缝、不锈钢隔板、七孔格子砖以及组合砖等进行了介绍,同时对在有预热技术的情况下,有效地提高风温问题进行了探讨。     

提高热风炉冷风充压效果的途径

热风炉充压时引起高炉内风压周期性的波动对稳定高炉操作不利，采取合理的充压控制方法可以减小入炉风压的波动。文章重点介绍了冷风阀小阀充压，旁通阀充压工艺和充排压新工艺。充排压工艺具有节能，缩短充排压时间等优点，基本上消除了高炉内压力周期性的波动现象，获得了较好的充压效果。