Welding technology in oil-field construction in China

Ｗｅｌｄｉｎｇｔｅｃｈｎｏｌｏｇｙｉｎｏｉｌ－ｆｉｅｌｄｃｏｎｓｔｒｕｃｔｉｏｎｉｎＣｈｉｎａ￥ＨＯＵＸｉａｎｚｈｏｎｇ（ＤａｑｉｎｇＯｉｌＦｉｅｌｄ）Ａｂｓｔｒａｃｔ：Ｔｈｉｓｐａｐｅｒｉｎｔｒｏｄｕｃｅｓｔｈｅａｐｐｌｉｃａｔｉｏｎａｎｄｄｅｖｅ...     

Tungstenite in China

The tungstenite is a blank space in detailed list of China's minerals.This blank had been fil-led in by Prof.Peng Mingsheng of Central South University of Technology recently.Thetungstenite was discovered at Shizhuyuan Nonferrous Metals Mine.This discovery is not only     

Role of misfit in precipitation crystallography in non-ferrous metals

The crystallography and morphology of precipitates in different systems were rationalized based on the optimum matcing conditions. The interfaces that obey these conditions were conveniently identified in reciprocal space, in terms of three Ag＇s parallelism rules. The theoretic basis of the O-lattice and CSL/DSC theory for these rules was provided briefly. Examples of small lattice misfit system （a Ti alloy）, and large lattice misfit systems （A1 and Mg alloys） were presented. The effect of lattice parameters on the orientation relationship and morphology was also discussed.     

Microstructure evolution mechanism in adiabatic shear band in TA2

The microstructure evolution mechanism in adiabatic shear band in commercial pure titanium (TA2) at high strain rates(γ≈l0^5 - 10^6/s) were studied. The nanosized recrystallized grains (about 50 nm in diameter) within the center of adiabatic shear band (ASB) were observed by means of transmission electronic microscope (TEM). A Rotational Dynamic Recrystallization (RDR) mechanism can explain the microstructure evolution (i. e. nanosized grains were formed within 5 - 10μs) in ASB. Kinetics calculations indicate that the recrystallized small grains are formed during the deformation and don‘t undergo significant growth by grain boundary migration after deformation.     

Small angle X-ray scattering used in precipitation in AlZnMgCuLi alloy

1　INTRODUCTION7XXXseriesalloysareusedextensivelyinaerospaceindustry .Inrecentyears ,developinghighstrengthandlowdensitymaterialsisthemainaimformostresearchers .Al Lialloyshavemanymeritssuchashighspecificstrength ,highspecificmodulusandlowdensity .InordertotakeadvantageofAl Lialloys merits ,Lihasbeenaddedtonormalaluminumalloy .ManynewalloysystemsweredevelopedsuchasAl Cu Li,Al Cu Mg LiandAl Mg Lialloys[1] .Manystudieshavealsobeenfocusedon 7XXXseries(AlZn MgCu)containingLi.The pr…     

Significant Discovery in Palaeoanthropology

An ape-man skull-fossil has been excavated in a karst near the city Nanjing.This is the firstevent that such a kind of discovery occurred to the south of Yangzi River.Palaeoanthropologists suggest that this is an important discovery in palaeoanthropology afterthe Sinanthropus pekinensis,the Sinanthropus lantienensis and the Sinanthropus yuanmounensis     

Welding research in China

ＷｅｌｄｉｎｇｒｅｓｅａｒｃｈｉｎＣｈｉｎａ￥ＺＨＯＵＺｈａｏｗｅｉ（ＨａｒｂｉｎＲｅｓｅａｒｃｈＩｎｓｔｉｔｕｔｅｏｆＷｅｌｄｉｎｇ（１５００８０））Ａｂｓｔｒａｃｔ：ｉｎｔｈｉｓａｒｔｉｃｌｅ，ｔｈｅａｕｔｈｏｒｔｏｕｃｈｅｓｏｎｗｅｌｄｉｎｇｒ...     

New advances for cast iron welding in China in last decade

ＮｅｗａｄｖａｎｃｅｓｆｏｒｃａｓｔｉｒｏｎｗｅｌｄｉｎｇｉｎＣｈｉｎａｉｎｌａｓｔｄｅｃａｄｅ￥ＳｕｎＤａｑｉａｎ；ＲｅｎＺｈｅｎａｎａｎｄＺｈｏｕＺｈｅｎｆｅｎｇ（ＪｉｌｉｎＵｎｉｖｅｒｓｉｔｙｏｆＴｅｃｈｎｏｌｏｇｙ．Ｃｈａｎｇｃｈｕｎ）Ａｂｓ...     

Development of welding technique in architectural and construction industry in China

ＤｅｖｅｌｏｐｍｅｎｔｏｆｗｅｌｄｉｎｇｔｅｃｈｎｉｑｕｅｉｎａｒｃｈｉｔｅｃｔｕｒａｌａｎｄｃｏｎｓｔｒｕｃｔｉｏｎｉｎｄｕｓｔｒｙｉｎＣｈｉｎａ￥ＺＨＯＵＷｅｎｙｉｎｇａｎｄＺＨＡＮＧＹｏｕｑｕａｎ（ＧｅｎｅｒａｌＢｕｉｌｄｉｎｇａｎｄＣｏｎｓｔ...     

Reducing porosity in thin‐sheet welded joints in titanium alloys

The gas metal arc welding process has wide industrial applications; however, its use in the production of pressure vessels has been limited, because the welds produced do not comply with the requisites imposed by the standards that govern construction of these pieces of equipment. This work was intended to study the influence of shielding gas mixtures on ASTM A 516 grade 70 steel. Three different gas mixtures were used containing varying levels of argon, helium, carbon dioxide and oxygen. As a first step, weld beads were deposited on plates with the gas mixtures tested and morphological analyses were made of the welds obtained. Multi-pass welds were then made on joints with a ‘V’-shaped groove, for cryogenic Charpy tests. Study of the morphology of the weld beads showed that an increase in the helium gas caused greater fusion around the edges of the beads, to the detriment of penetration. The results of the Charpy test showed the best results for the mixtures that contained helium. However, oxide inclusions were seen in the samples tested, with fewer inclusions in welds produced with the helium mixtures. The higher incidences of inclusions point to a direct relationship with the lowest values of energy absorbed.     

Progress in flotation de-silica

1　INTRODUCTIONBayer sprocessisatypicalmethodtoproducea luminumoxidefrombauxite .Forthediasporic baux ite ,theBayer sprocesscaneconomicallyproducealu minumoxideonlywhenthemassratioofAl2 O3toSiO2 >10 .However ,inChina ,thealuminumoxidewasmainlyproducedbyusing“sinteringprocess”or“in parallelBayer sinteringcombination process”technologiesbecausethediasporic bauxiteischarac terizedbyhighcontentofaluminumoxideandsilicabutlowAl2 O3/SiO2 (average 5 6 ) .Thesetwotech nologieshavetheproble…     

Germanium Production in China

1 .Introduetion Germanium differs from other metals for its semieonducting ProPerties.The first major stud-ies of solid state Physies in utilizing semieondueting ProPerties were due Primarily to the availabili-ty of high Purity germanium.P一tyPe germanium erystal ean be obtained by doPing high Puritygermanium with 3 valenee element as indium,gallium or boron.Similarlyn一tyPe germanium erys-tal can be doPed with 5 valenee element     

The welding technique in building the largest bronze Buddha in the world

The Temple-of-heaven Buddha,situated on the Mo Yu Peak of DaYu Hill in Hong Kong,is the largest open air bronze statue of Buddha in theworld.The key technique of the Buddha developing project is the welding pro-cess.This paper states the adoption of combination of MIG and TIG processwith special filler wires in the Buddha project,and the satisfactory resultsachieved.     

Microstructural evolution in adiabatic shear bands in Ta and Ta–W alloys

Microstructural evolution of adiabatic shear bands originated due to high strain, high strain rate deformation in Ta and Ta–W alloys has been examined. Tests were performed using a specially designed stepped specimen in a Hopkinson bar. Upon completion of the deformation, the region is cooled to below one half of the temperature achieved during adiabatic heating in less than one millisecond. Microstructural characterization of the shear bands was performed using optical microscopy as well as scanning and transmission electron microscopy. No evidence of recrystallization within the shear bands could be found. This is in contradiction with several recent reports, which claim that recrystallization may take place at these stringent time and temperature conditions. These studies, however, do not take into account the kinetics of boundary refinement processes, which are a distinctive characteristic of a recrystallized microstructure. It will be shown that the absence of recrystallization in Ta and Ta–W adiabatic shear bands can be predicted by a progressive subgrain misorientation (PriSM) recrystallization model, applied successfully in previous studies to predict the microstructure evolution in copper adiabatic shear bands.     

The Antimony Production in China

A full account of the antimony production in China may be found in two new books,respectively titled“Antimony”and“The Metallurgy of Antimony”.The former is published inChinese in 1987 by Metallurgical Industry Press,Beijing and the latter published in English in 1988by Central South University of Technology Press.The present paper is only an outline extractedfrom the two books.It is divided into four parts,namely:a brief historical account of antimony     

Machinability analysis in turning tungsten–copper composite for application in EDM electrodes

Electro-discharge machining (EDM) is widely used in tooling industry, where it is applied on materials, which are too hard to be machined with conventional techniques. The tungsten–copper is broadly used as an EDM electrode for machining of die steel and tungsten carbide workpieces. As, tungsten–copper electrode is more costly than conventional electrodes, there is a need to understand the machinability aspects in turning of this material. Hence, an attempt has been made in this paper to study the effects of cutting conditions on machinability characteristics such as cutting force, feed force, depth force, machining force, power, specific cutting force, arithmetic average surface roughness and maximum peak to valley height during tungsten–copper turning with K10 carbide cutting tool. The response surface methodology (RSM) based second order mathematical models of machinability aspects are developed using the data obtained through full factorial design (FFD). The adequacy of the machinability models is tested through the analysis of variance (ANOVA). The response surface analysis reveals that a combination of higher cutting speed with low-to-medium feed rate is advantageous in reducing the forces, power and surface roughness, which in turn increases the specific cutting force.     

Alignment behavior of MnBi phase in Bi-Mn alloy solidified in static magnetic field

1　INTRODUCTIONRegularstructuresinmaterialsarealwayspre paredtoimprovetheirproperties .Itiswellknownthatpowderedferromagneticmaterialscanbeorientedinastaticmagneticfield .Inrecentyearshighmag neticfieldwasappliedtoinducealignmentofparticlesinsomenonferromagneticmaterialswithanisotropicmagneticsusceptibilityinroomtemperature ,suchasparamagneticYBa2 Cu3O7ceramic[1] anddiamagneticgraphite[2 ] .Ifthematerialshavearesidualanisotropyintheirmagneticsusceptibilityatahightemperature ,theycanbetex…     

Chemical bonding of oxygen in intergranular amorphous layers in high-purity β-SiC ceramics

An amorphous intergranular layer, 0.4 nm thick, is found by high-resolution transmission electron microscopy of β-SiC ceramics fabricated by the HIP glass-encapsulation technique without the use of additives. The intergranular layer is found to contain oxygen, which may also be present in the SiC grains near the grain boundary. The mean composition of the intergranular layer is determined to be SiO_0.10±0.01C_0.93±0.04, whose C/O ratio is close to a hypothetical Si-oxycarbide stoichiometry. Electron energy loss spectroscopy shows that both the Si-L₂₃ and O-K edges from the intergranular layer are distinctive compared to those of SiC and/or SiO₂. This provides direct evidence of the presence of oxygen in a chemical environment different to that in glassy SiO₂, that can also be found in the intergranular layer. First principle calculations by the DV-Xα method using an interface model cluster, satisfactorily reproduce the chemical shifts of the energy loss near edge structure (ELNES) for both the Si-L₂₃ and O-K edges.