THEORETICAL INVESTIGATION ON BY-ONLY-CURRENT ELECTROMAGNETIC SEPARATION OF INCLUSION FROM MOLTEN METALS

The electromagnetic field under applied AC and DC current in round and rectangular pipe was systematically investigated, then a concept of "equivalent current density" was proposed for evaluating the inhomogeneous electromagnetic pinch force, and the mono-component removal efficiency and the overall removal efficiency of inclusion were formulated. It is founded that flat pipe is superior to round pipe for the electromagnetic removal of inclusion, and DC current can get a higher removal efficiency than A C current due to absence of skin phenomenon. Under usual condition, a removal efficiency of 52% for 10μm inclusion or more than 92% for 20μm inclusion can be achieved by imposing a current density of 3×106A/m2 in a flat pipe.     

EFFECTS OF SPECIFIED BLANK SIZE ON BODY WRINKLING DURING HYDRODYNAMIC DEEP DRAWING OF TAPERED RECTANGULAR BOX

1.~nonHydridapawhcdeepdrawing(HDD)belongstothefieldofsheetmetalfoeingandcanbeaPPliedinthefieldofautomotive,aerospace,drilitaryindustryetc.Ithasbeenrecognizedwidelyintheworld["'j.Fig.Ishowsitsprinciple:TheliqUidthatisfilledinthe~ngdiecavitywillbepressedwhenthepunchgoesdownsothattheeffectoffrictionkeepingandoverflowlubricatingcanbeformed,astherestilt,thefoeinglicitofsheetmetalwillbeimprovedareailvandthegualitVofthefinishedpartswillbeup~ed.BecauseofmanyadvantagesofHDDprocees,ithasbeenwidelys…     

LOCALIZED CORROSION OF MICROCRYSTALS OF 1Crl8Ni9Ti STAINLESS STEEL

The resistances against localized corrosion of 1Cr18Ni9Ti microcrystals with normal grainsize and bcc structure obtained hy magnetron sputtering have been compared.The two kindsof microcrystals with (110) and (211) textures respectively were obtained under differentsputtering conditions.Both microcrystals were found to have better resistance against local-ized corrosion than the crystal with normal grain.The microcrystal with (110) preferredorientation has larger resistance to localized corrosion than that with (211) preferredorientation.     

TEMPERATURE DEPENDENCE UPON VISCOSITY OF Ni-P ALLOY ON AMORPHOUS FORMATION

The viscous flow of amorphous alloys near T_gis closely related to the viscosity of liquid alloys.On the basis of the measured surface tension and density for Ni-P binary alloys,the correla-tion between the viscosity of the melt and viscous flow process of the amorphous alloy is inves-tigated.The relationship between viscosity and temperature for Ni-P alloys going from liquidto amorphous solid may be described by the following formula:     

MICROSTRUCTURE AND MECHANICAL PROPERTIES OF Mg-Li ALLOY WITH Ca ADDITION

Mg-9wt%Li-2wt%Zn alloy was prepared and studied in this article. The addition of Ca to the alloy from 0.1wt% to 1wt% can refine the α-Mg and the best effect of refinement occurs when Ca content is 0.4wt%-0.5wt%. The billets can be rolled to thin sheets at room temperature, from which it is obvious that the addition of Ca improves alloys ormalin. while it decreases with the excess addition of Ca. The results also show that the ultimate tensile strength （UTS） and yield strength （YS） of the alloy with lwt% Ca may rise by 28% and 25%, respectively, however, the elongation decreases. It is clarified that the adsorption of proper Ca on the grain boundaries refines α-Mg and improves the tensile properties, but the presence of excess Ca and stable Ca2Mg6Zn3phase worsens the elongation.     

德国的焊接生产(2)

4　人才培养德国社会教育的普及程度已达到世界先进水平。在她的 343所国家大学里 ,有超过 180万的大学生在学习。德国实行不间断的普通职业教育方法 ,包括人员的培训及考核。在很多部门中 ,德国的专家培训和考核大纲标准被当作欧洲和国际相应项目标准的研究基础。从 2 0 0 0年开始 ,德国在教育上投资的年增长额为 10 0万马克。这完全符合世界上向高科技人才培训增加投资的趋势。在德国 ,有将近 4 6万人在科技及为科技服务的领域里工作。德国政府拨出 2 .2 7%的ＢＢП(国民经济总产值 )来发展国家的科学技术 ,在这方面 ,她在日本 (2 .98% )…     

钨粉粒度对棒材和粗丝性能的影响

引言主要由于钨具有熔点高达3400℃等物理特性,人们已经将其广泛地用于制造白炽灯、电子管和 X 光管等。生产钨丝是一个很复杂的过程,这一方面是因为钨粉(制造钨丝的原料)又硬又脆、难以压制,另一方面则是因为为了取得成品丝材而要进行大约80次作业(每一个工     

Ti9Al合金的氢塑性效应

采用真空自耗电弧炉熔炼制备Ti9Al合金，通过渗氢处理显著提高氢含量，在凸轮塑性试验机ЧПИ-2上以10mm／min的速度进行热模拟试验。研究发现：氢可以降低Ti9Al合金的相变温度，扩大α β区的温度范围；氢作为卢稳定剂会妨碍或完全抑制以Ti3Al为基的α2相的析出；钛合金的氢合金化可促使卢相在更低温度下稳定化，明显地提高了Ti9Al合金塑性。     

Study on bioleaching of primary chalcopyrite ore with thermoacidophilic archae

A high temperature-tolerating thermoacidophilic archae （TA） was isolated from water samples collected from a hot sulfur-containing spring in the Yunnan Province, China, and was used in bioleaching experiments of a low-grade chalcopyrite ore. The TA grow at temperatures ranging from 40 to 80℃, with 65℃ being the optimum temperature, and at pH values of l.5 to 4.0, with an optimum pH value of 2.0. The bioleaching experiments of the chalcvpyrite ore were conducted in both laboratory batch bioreactors and leaching columns. The results obtained from the bioreactor experiments showed that the TA bioleaching rate of copper reached 97% for a 12-day leaching period, while the bioleaching rate was 32.43% for thiobacillus ferrooxidans （Tf） leaching for the same leaching time. In the case of column leaching, tests of a two-phase leaching （196 days）, that is, a two-month （56 days） Tf leaching in the first phase, followed by a 140-day TA leaching in the second phase were performed. The average leaching rate of copper achieved for the 140-day TA leaching was 195mg/（L.d）, while for the control experiments, it was as low as 78mg/（L .d） for the Tf leaching, indicating that the TA possesses a more powerful oxidizing ability to the chalcopyrite than Tf Therefore, it is suggested that the two-phase leaching process be applied to .for the heap leaching operations, whereas, the TA can be used in the second phase when the temperature inside the heap has increased, and the primary copper sulfide minerals have already been partially oxidized with Tf beforehand in the first phase.