An Industrial Perspective on Magnesium Alloy Wheels: A Process and Material Design

Light weights wheels improve vehicle performance with respect to road handling, cornering as well providing fuel economy and reduced greenhouse gas emissions. Aluminum wheels are currently used in many models and are produced usually by low pressure assisted gravity casting. Important property requirements are fatigue strength, pressure tightness, tensile strength, impact resistance, and corrosion resistance. Many attempts have been made to convert aluminum road wheels to magnesium. Race cars and some of the high end models (Porsche, Ferrari, etc.) have used magnesium wheels. These wheels have been gravity cast or forged. Viable corrosion protection systems have been developed and magnesium wheels have been used with success on these models. To use magnesium on more modest models is a challenge due to cost issues. Higher productivity casting processes or more cost effective coating systems need to be utilized. The project consists of selecting magnesium alloys for road wheels, examining the possible cost effective casting processes and corrosion protection systems, evaluating the cost per one wheel and comparing it to aluminum wheel costs. The wheels will also be compared with respect to fatigue and impact properties, pressure tightness, and corrosion.

Tennantite and Enargite Rejection in the Copper Flotation—A Mini-Review

With the development of arsenic removal technologies, biological method and sulfide method have been applied in industrial fields, other methods have also been applied in arsenic-containing copper flotation, including coagulation process, ion exchange method, direct precipitation method and so on. In the paper, a short review on the progress of arsenic removal technologies of copper flotation during the last decade is presented, and the importance and the trend of arsenic removal are discussed. The existing and possible strategies of improving copper recovery in porphyry copper ores and rejection of penalty elements such as Tennantite and Enargite in copper flotation concentrates are also presented.

Consideration of green intelligent steel processes and narrow window stability control technology on steel quality

In order to promote the intelligent transformation and upgrading of the steel industry, intelligent technology features based on the current situation and challenges of the steel industry are discussed in this paper. Based on both domestic and global research, functional analysis, reasonable positioning, and process optimization of each aspect of steel making are expounded. The current state of molten steel quality and implementation under narrow window control is analyzed. A method for maintaining stability in the narrow window control technology of steel quality is proposed, controlled by factors including composition, temperature, time, cleanliness, and consumption(raw material). Important guidance is provided for the future development of a green and intelligent steel manufacturing process.

Characterization and separation of pyrite from Abu Tartur black shale

This work aimed for pyrite separation from Abu Tartur black shale as a source of sulfur to be an added economic value of Abu Tartur area. The considered samples in the present work were collected from a core drilled in Abu Tartur plateau representing the pyrite-rich black shale of the U. Cretaceous age.Sample characterization was carried out using petrographic microscope, XRD, DTA/DTG, C/S and XRF techniques. Clay minerals, silt-sized quartz, calcite, and hematite were the main minerals associating pyrite(5.34%). Liberation behavior of the sample was about 80% below 5 lm.Sample processing was achieved through one-day soaking followed by classification using 1 inch Mozley hydro-cyclone where about 35.5% by weight went to underflow and 64.5% went to overflow.The underflow product was subjected to an advanced gravity separation process using SB-40 Falcon Concentrator through a CCD statistical design prepared by Design-Expert 6.0 software proposed to optimize the separation process through a study for the effects of frequency(Hz) and water pressure(Psi) on both assay and recovery of the sulfur-rich heavy fraction.A heavy concentrate weighed 10.90% with inorganic sulfur content reached 11.37%(21.24% pyrite) with overall recovery(50.01%) was obtained after two cleaning at the optimum conditions.

冷变形和热处理对TC21钛合金显微组织和力学性能的影响

研究冷变形、不同冷却速率的固溶处理以及时效处理对TC21钛合金(6.5Al-3Mo-1.9Nb-2.2Sn-2.2Zr-1.5Cr)显微组织、硬度和磨损性能的影响。对退火后试样进行15%(高度降低)的室温冷变形处理;然后,将样品在920℃下进行15min固溶处理,再分别进行不同冷却速率的水淬(WQ)、空冷(AC)和炉冷(FC)至室温;最后,将样品在590℃下时效4 h。结果发现,对于经固溶处理、空冷和时效处理后的样品,其残余β相中有二次α片状晶体析出。WQ和时效处理样品的硬度最高,为HV 470,这是由于存在大量残余β相(69%),而FC样品的硬度最低,为HV328。固溶处理后再时效处理可显著提高试样的耐磨性能,经水淬和时效处理后试样的耐磨性能可达到退火试样的122%。

磷掺杂TiO2薄膜的制备与表征及其可见光照射下光催化降解邻苯二甲酸丁苄酯性能(英文)

P‐doped TiO2 (PTIO) thin‐films with different P contents were prepared using a sol‐gel method. The thin‐film samples were characterized using various techniques. The photocatalytic activity was evaluated by decomposing butyl benzyl phthalate under visible‐light irradiation. The results showed that the transformation of anatase to the rutile phase was inhibited and grain growth of TiO2 was prevented by P doping. The results confirm that the doped P atoms existed in two chemical forms, and those incorporated in the TiO2 lattice may play a positive role in photocatalysis. The high photocatalytic activities of the PTIO thin‐films may be the result of extrinsic absorption through the creation of oxygen vacancies, rather than excitation of the intrinsic absorption band of bulk TiO2 . The PTIO can be recycled with little depression of the photocatalytic activity. After six cycles, the photocatalytic activity of the PTIO film was still higher than 98%.

Investigation of improving wear performance of hypereutectic 15%Cr-2%Mo white irons

This study aimed at optimizing impact toughness and abrasion wear resistance of 15%Cr-2%Mo hypereutectic abrasion-resistant white irons. The effects of dynamic solidification, niobium addition, combined action of them and heat treatment have been investigated. Investigations were performed by means of the image analyzer, scanning electron microscopy (SEM), energy-dispersive spectrometry (EDS) and X-ray diffraction. Impact toughness and abrasion wear resistance tests were conducted. Fracture and worn surfaces were studied. Results indicated that microstructural control during solidifciation is the most valuable tool to attain the optimum combination between impact toughness and wear resistance in hypereutectic iron. Combined action of Nb addition and dynamic solidifciation improves impact toughness and wear resistance even more than the action of each individual factor. In the as-cast condition, impact toughness and abrasion resistance were increased after dynamic solidification compared to statically solidified one by 71.4% and 10%, respectively. This enhancement was increased to 114.3 % and 28.8 % by adding 2% Nb. Lower tempering temperature of 260°C exhibits better impact and abrasion resistance than the sub-critical tempering temperature of 500°C.

添加晶粒细化剂硅对Ti-6Al-4V合金组织和性能的影响(英文)

采用真空感应凝壳熔炼工艺在石墨模中制备Ti-6Al-4V和Ti6Al4V0.5Si两种钛合金。将硅作为一种晶粒细化剂加入到Ti-6Al-4V合金中,考察添加硅对铸态和模锻态Ti-6Al-4V合金组织和性能的影响。铸态合金先在900°C下进行热模锻处理,然后分别进行两种不同的热处理。一种是将模锻样品在1050°C下保温30min,然后水淬以获得细小的层片状组织;另一种是将模锻件在1050°C下保温30min,然后再在800°C下保温30min,以获得粗大的层片状组织。Ti6-Al-4V合金中添加0.5%Si后,铸态合金的晶粒尺寸从627μm减小到337μm,其极限抗拉强度增加约25MPa。具有细小、层片状组织的Ti-6Al-4V0.5Si合金的最大极限抗拉强度为1380MPa,在Hank溶液和NaCl溶液中的腐蚀速度分别为1.35×106和5.78×104mm/a。Ti-6Al-4V合金中添加0.5%Si后,在低滑动速度下的磨损率降低50%,在高滑动速度下的磨损率降低约73%。

New Approach to Cluster Synchronization in Complex Dynamical Networks

在这篇论文，分布式的控制策略被建议让一个复杂动态网络完成簇同步，它意味着在一样的组的节点完成一样的同步状态，当在不同的组的节点完成不同同步状态时。簇同步状态的本地、全球的稳定性被分析。而且。

A CFD model for gas uniform distribution in turbulent flow for the production of titanium pigment in chloride process

The fluid dynamic behavior of feeding gas(Ti Cl4) in an annular channel affects the combination of O2 and Ti Cl4 in an oxidation reactor, a key piece of equipment in titanium pigment production. The numerical procedure was validated by a 3-dimensional gas flow in the annular channel. Applying the validated model, the flow characteristics of Ti Cl4 in the oxidation reactor with a tangential inlet were simulated and characterized. The flow distribution with five rectifying rings of different structure was simulated and analyzed. The results showed that the rectifying ring improved the distribution uniformity of the pressure and outlet velocity. Compared to the original case without a rectifying ring, the non-uniformity of the pressure and outlet velocity could be reduced by up to91% and 69% respectively. The rectifying ring #5, which can be installed and adjusted easily, is more effective in realizing even distribution. In addition, installation of the rectifying ring effectively reduced the circulating flow in an annular channel as well as the total energy loss.

Phosphogypsum Pyrolysis by Adding Mineralization Agent:Process and Mechanism

In order to decrease energy consumption for phosphogypsum( PG) pyrolysis process,a pilot-scale vertical-retort furnace was designed initiatively,and then mineralization agent was added to pyrolysis mixture. Calcium fluoride( CaF_2) was proven to be a suitable mineralization agent, and the optimal parameters were: pyrolysis temperature 960 ℃,carbon-sulfur mole ratio 0. 7,reaction time 50 min,and CaF_2 dosage 4% by weight. Under this condition,PG decomposition and sulfur dioxide( SO_2) conversion were up to 89. 6% and 67. 3%,respectively. CaF_2 could lead to the formation of fluosilicate complexes,and facilitate PG decomposition at a low temperature. During pyrolysis process, calcium sulfide( CaS) was an inevitable intermediate substance,and only a part of total sulfur in the feedstock could be converted to SO_2.

Desulfurizer desulphurization kinetics by the injection method

To obtain a better desulphurization effect in hot metal, suitable desulfurizers should be selected first according to thermodynamics. However, the effect of desulphurization is also strongly affected by kinetics. The conditions of different desulfurizers （Mg, CaC2, and lime） penetrating into hot metal, the rising up velocity in iron melt, residence time, and dissolving time are theoretically calculated and analyzed. The results are helpful to select the desulphurization process and equipment and to improve the desulphurization effect.

Ni/TiO_2-SiO_2上光催化重整葡萄糖以低CO选择性制H_2(英文)

Nano-sized Ni particles on TiO2-SiO2 were synthesized by the two methods of photo-assisted deposition(PAD) and impregnation.H2,which is a promising energy carrier,with a low CO concentration was produced by the photocatalytic reforming of glucose(a model biomass) on the Ni/TiO2-SiO2 catalyst.The supported Ni enhanced the rate of H2 production while it suppressed CO selectivity.The catalysts were characterized by X-ray diffraction,X-ray absorption fine structure,transmission electron microscope,and nitrogen adsorption analysis.Both H2 production and CO selectivity were strongly dependent on the preparation method,and PAD-Ni/TiO2-SiO2 was the better catalyst for H2 production with the lowest CO concentration.

Sources of the Laoxiongdong carbonate-hosted Pb–Zn deposit in Southwest China:constraints from S–Pb–Zn isotopic compositions

The Sichuan-Yunnan-Guizhou(SYG)Pb-Zn mineral province,which has significant Pb-Zn repositories in China,is situated in the western Yangtze Block.Despite decades of research,the Pb-Zn source of deposits is still disputed between the basement rocks,sedimentary wall rocks,or the Emeishan flood basalts.The newly-discovered Laoxiongdong Pb-Zn deposit is hosted by the Late Ediacaran Dengying Formation in the SYG province.Moreover,the Laoxiongdong orebodies lie between regional deep faults and close to the Proterozoic basement and Emeishan basalts.Hence,this deposit represents a good case study on the ore-forming material source for the regional Pb-Zn mineralization.The Laoxiongdong Pb-Zn ores are massive,vein,or disseminated and have mainly sphalerite,galena,pyrite,quartz,and calcite.In this paper,we present new sulfide S-Pb-Zn isotope data of the deposit.The sulfideδ34SCDT values(+11.8 to+16.5‰)suggest that the reduced sulfur was mainly sourced from evaporites in the Late Ediacaran-Cambrian sequences.Pb isotopic ratios(206Pb/204Pb=18.004-18.107,207Pb/204Pb=15.652-15.667,and 208Pb/204Pb=38.037-38.248)suggest that the lead metal was primarily originated from the basement rocks.The sphaleriteδ66Zn values(+0.16 to+0.37‰)are also highly similar(within error)to those of basement rocks(+0.10 to+0.34‰),suggesting a basement-rocks zinc source with minor contributions from the carbonate host rocks and Emeishan flood basalts.The narrow sphalerite Zn isotopic range(0.21‰)also indicates that the Zn isotopic fractionation between the sphalerite and initial fluid was limited during the sphalerite ore precipitation.Therefore,we propose that both the Late Ediacaran Dengying Formation rocks and Proterozoic basement rocks were important ore-forming material source for the Laoxiongdong deposit,whereas the Emeishan flood basalts represent only a minor ore-material source.

The Influence of Longitudinal Magnetic Field on the CO_2 Arc Shape

The COarc welding was carried out under a longitudinal magnetic field,and the arc shape has been studied by using a high-speed camera.From the camera images,we know that under the action of the longitudinal magnetic field,the upper end of the arc will constrict and the lower end of the arc will expand.It would become a bell-type shape and rotate at a highspeed in the optimum range of magnetic field parameters.The arc shape was simulated using a mathematical model,which was established based on experiment data and theoretical knowledge,and mechanism analysis has been carried out regarding the effect of longitudinal magnetic field on COwelding arcs.

Thermodynamic Calculation for Silicon ModifiedAISI M2 High Speed Tool Steel

During high speed tool steel production up to 0.2 wt % silicon is added, primarily to react with oxygen e.g. silicon acts as a de-oxidizer. If more than 0.2 wt % silicon is added, it serves to improve the deep hardening properties. An addition up to ~1 wt % silicon provides hardness and improves temper-stability but reduces the ductility. At high concentration, silicon causes embrittlement. Alloying with silicon raises the solubility of carbon in the matrix and hence the as-quenched hardness. It has virtually no influence on the carbide distribution, but it promotes the formation of M6C type carbides. The many essential alloy additions to iron (C, W, Mo, V, Cr, Si) make the high speed tool steel, HSS a complex multi-component system. Its complete experimental investigation would require enormous time and effort. Instead, the CALPHAD method has been successfully used for computation of phase equilibrium the multi-component HSS system. In the present work, the Thermo-Calc program has been applied to the system Fe-C-Cr-W-Mo-V-Si with the thermodynamic information contained in the solid-solution-database of the TCFE. In the present work, some temperature-concentration diagrams for silicon modified AISI M2 steel are presented by calculated quantities (melting and transformation temperatures, amount and compositions of phases). Calculated data are compared with standard AISI M2 high speed tool steel.

A novel method for improving cerussite sulfidization

Evaluation of flotation behavior, solution measurements, and surface analyses were performed to investigate the effects of chloride ion addition on the sulfidization of cerussite in this study. Micro-flotation tests indicate that the addition of chloride ions prior to sulfidization can significantly increase the flotation recovery of cerussite, which is attributed to the formation of more lead sulfide species on the mineral surface. Solution measurement results suggest that the addition of chloride ions prior to sulfidization induces the transformation of more sulfide ions from pulp solution onto the mineral surface by the formation of more lead sulfide species. X-ray diffraction and energy-dispersive spectroscopy indicate that more lead sulfide species form on the mineral surface when chloride ions are added prior to sulfidization. These results demonstrate that the addition of chloride ions prior to sulfidization can significantly improve the sulfidization of cerussite, thereby enhancing the flotation performance.

碳化物弥散强化高熵合金的耐磨性、硬度和显微组织

对(CrFeCoNi)高熵合金(HEA)添加5 wt%~20 wt%的WC颗粒进行增强,并通过粉末冶金制备。首先将混合粉末在700 MPa下压实;然后,在真空炉中在1200℃下烧结90 min,研究了烧结样品的密度、相组成和微观结构。估计了硬度、抗压强度、耐磨性和热膨胀系数(CTE)。结果显示添加WC后,合金的密度得到提高。XRD结果表明合金中形成了新的FCC碳化铬相。扫描电子显微镜(SEM)结果显示碳化物相在合金基体上分布良好。通过增加WC含量,CTE逐渐降低。添加WC可以提高抗压强度。建立了数学模型以预测HEA样品的强度行为。随着WC含量的增加,合金的硬度提高约20.35%,此外,无WC HEA的磨损率为1.70×10^(-4) mm^(3)/(N·m),大约是添加20 wt%WC HEA磨损率(3.81×10^(-5) mm^(3)/(N·m))的4.5倍,这意味着合金的耐磨性随WC含量的增加而得到显着改善。