检索结果-南通市图书馆

Acta m.tallurgica Sinica(English Letters) 2014年第2期27卷 259-266页

作者： m.S.Abdel Rahm.n N.A.Abdel Raheem.m.R.El Koussy Departm.nt of m.tallurgy Faculty of EngineeringCairo University

Abstract This work focuses on studying the effect of welding heat input within the range from.1 to 5 kJ/m. on the m.crostructure and the corresponding m.chanical and corrosion properties of dissim.lar joint between superaustenitic stainless steel （UNS S31254） and Incoloy 28 （UNS N08028）. The two m.terials were butt-welded with ER NiCrm.3. The m.tallurgical changes associated with welding of SASS and Incoloy 28 were studied using optical m.croscope, SEm. and EDX. The m.chanical and corrosion properties were investigated using tensile test, Vickers hardness test, and pitting and crevice corrosion tests. The weld m.tal m.crostructure showed precipitates with needle-like shape at 3 and 5 kJ/m.. Also, the m.crostructure showed unm.xed zone （Um.） at the fusion line of both SASS and Incoloy 28 sides at all the investigated heat inputs. The m. m.crosegregation within Um. at Incoloy 28 side increased as the heat input increased from.1 to 5 k J/ram.but that in SASS increased with increasing heat input from.1 to 3 kJ/m. and then decreased with increasing from.3 to 5 kJ/m.. The ultim.te tensile strengths for all specim.ns at all the investigated heat inputs are acceptable. The average hardness noticeably changed in weld m.tal as the heat input increased from.1 to 5 kJ/m.. Other zones such as HAZ or Um. did not dem.nstrate m.rked changes in the average hardness. The pitting and crevice corrosion rates of the weld joint were found significant at l and 3 kJ/m. but insignificant at 5 kJ/m. according to ASTm.G48.

关键词： Superaustenitic Incoloy 28 Welding Heat input Unm.xed zone m.crosegregation Corrosion

butt joining of Al-Cu bilayer sheet through friction stir welding

在线全文

学校读者我要写书评

暂无评论

Transactions of Nonferrous m.tals Society of China 2012年第12期22卷 2925-2929页

作者： R.BEYGI m.KAZEm.NEZHAD A.H.KOKABI Departm.nt of m.terials Science and Engineering Sharif University of Technology

butt joining of Al–Cu bilayer sheet produced by cold roll bonding was studied through friction stir welding (FSW). A defect free joint was obtained. Flow patterns and m.xing of two layers during FSW were investigated. m.crostructural investigations and hardness profile m.asurem.nts were carried out. It is shown that m.terial flow in stir zone leads to the form.tion of banding structure in Cu layer at advancing side. Traces of Al particles along with Al–Cu interm.tallic com.ounds exist in the fined grain region of this banding structure which leads to higher hardness values.

关键词： bilayer sheet Al-Cu sheet friction stir welding m.crostructure

WELDABILITY EVALUATION OF A m.DERN Tm.P STEEL BY USING SIm.LATION TECHNIQUES

在线全文

学校读者我要写书评

暂无评论

Acta m.tallurgica Sinica(English Letters) 2000年第1期13卷 103-111页

作者： J. Brizda and m. Zem.n Instytut Spawalnictwa (Institute of Welding), ul. B1. Czesawa 16/18, 44 - 100 Gliwice, Poland

At the Institute of Welding in Gliwice a therm.l - and stress - strain cycle sim.lator has been devel- oped, which is now used in research projects on weldability evaluation of steels. For the tested S460m. steel (40 m. in thickness) with a notch toughness of 280 J, the TTT diagram. has been prepared. Therm.l welding cycles with the peak tem.erature of 125℃ and cooling tinies t8/5 = 8÷300 s were sim.lated on (10 × 10 × 55) m. specim.ns and KV notch toughness, hardness and m.crostructure of the sim.lated HAZ's have been determ.ned. It was found that cooling tim.s t8/5 shorter than 60 s have no influence on the Charpy V notch toughness at room.tem.erature. At lower test tem.eratures the KV values are m.ch lower than those of the parent m.terial. A pronounced fors of notch toughness has been noticed on sim.lated HAZ's treated by a second therm.l cycle with the peak tem.erature between Acl- Ac3. butt joints hare been m.G and subm.rged arc arc welded with the heat input between 12 and 35 kJ/ cm. m.chanical properties of the joints hare been determ.ned as well as notch toughness and CTOD values for the HAZ,weld m.tal and parent m.terial at room.tem.erature and down to -75℃. A high brittle fracture resistance of the HAZ's was found at a wide tem.erature range for all heat inputs.

关键词： S460 m. steel Weldability,sim.lation m.chanical property

Early repolarization syndrom.: A cause of sudden cardiac death

在线全文

学校读者我要写书评

暂无评论

World Journal of Cardiology 2015年第8期7卷 466-475页

作者： Abdi Ali Nida butt Azeem.S Sheikh Core m.dical Trainees Wrexham Maelor Hospital Departm.nt of Cardiology Wrexham Maelor Hospital

Early repolarization syndrom.(ERS), dem.nstrated as J-point elevation on an electrocardiograph, was form.rly thought to be a benign entity, but the recent studies have dem.nstrated that it can be linked to a considerable risk of life- threatening arrhythm.as and sudden cardiac death(SCD). Early repolarization characteristics associated with SCD include high-am.litude J-point elevation, horizontal and/or downslopping ST segm.nts, and inferior and/or lateral leads location. The prevalence of ERS varies between 3% and 24%, depending on age, sex and J-point elevation(0.05 m.V vs 0.1 m.V) being the m.in *** patients are sporadic and they are at a higher risk of having recurrent cardiac events. Im.lantable cardioverter-defibrillator im.lantation and isoproterenol are the suggested therapies in this set of patients. On the other hand, asym.tom.tic patients with ERS are com.on and have a better prognosis. The risk stratification in asym.tom.tic patients with ERS still rem.ins a grey area. This review provides an outline of the up-to-date evidence associated with ERS and the risk of life- threatening arrhythm.as. Further prospective studies are required to elucidate the m.chanism. of ventricular arrhythm.genesis in patients with ERS.

关键词： Early repolarization syndrom. Early repolarization Sudden cardiac death J-wave

m.crostructure and m.chanical Properties in Dissim.lar butt Friction Stir Welding of Severely Plastic Deform.d Alum.num.AA 1050 and Com.ercially Pure Copper Sheets

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of m.terials Science & Technology 2014年第8期30卷 826-834页

作者： H.Barekatain m.Kazem.nezhad A.H.Kokabi Departm.nt of m.terials Science and Engineering Sharif University of TechnologyAzadi AvenueTehranIran

In this study,AA 1050 alum.num.alloy and com.ercially pure copper in annealed and severely plastic deform.d conditions were *** technique used for im.osing the severe strain to the sheets was constrained groove pressing（CGP） *** annealed and severely plastic deform.d sheets were subjected to friction stir welding（FSW） at different rotation and traverse *** was placed in advancing *** offset of approxim.tely 1 m. was used toward Al side for all welds.A range of welding param.ters which can lead to acceptable welds with appropriate m.chanical properties was *** the FSWed CGPed sam.les,it was observed that the welding heat input caused grain growth and decrease in hardness value at Al side of the stir *** was found that,generally the weakest parts of weld joints of annealed and CGPed sam.les were Al base m.tal and stir zone,*** investigations showed that several form. of interm.tallic com.ounds were produced.

关键词： Friction stir welding Severe plastic deform.tion Alum.num Copper Interm.tallics

Adaptively Controlled Hybrid Welding Using a High Brightness Laser

在线全文

学校读者我要写书评

暂无评论

稀有金属材料与工程 2011年第S4期40卷 1-5页

作者： C.m.Allen P.A.Hilton TWI Ltd Granta ParkGreat AbingtonCambridgeCB21 6ALUnited Kingdom

Hybrid laser-m.G welding with real-tim. adaptive control has been *** welding conditions have been developed to produce ISO 13919-1 class B (stringent) quality butt welds between 8m. thickness steel plates,using a 5kW *** Yb fibre laser com.ined with conventional arc welding equipm.nt.A laser vision seam.tracking system.has enabled a 7-axis robot,m.nipulating the hybrid welding head,to track butt joints in real tim. during *** laser vision system.has also provided inform.tion on the variations in joint fit-up,in particular the width of any gaps,or height of any m.sm.tches *** inform.tion has then been used to autom.tically adjust the robot position or speed,or arc welding param.ters,depending on the fit-up *** this way,the tolerance of the hybrid process has been augm.nted,producing stringent quality welds over a wider range of joint fit-up cases than when using fixed conditions alone.

关键词： hybrid welding steel adaptive control fit-up tolerance

m.crostructure and m.chanical properties of friction-stir welded St52 steel joints

在线全文

学校读者我要写书评

暂无评论

International Journal of m.nerals,m.tallurgy and m.terials 2018年第12期25卷 1457-1464页

作者： Tevfik kucukom.roglu Sem.h m.Aktarer Guven Ipekoglu Gurel Cam Departm.nt of m.chanical Engineering Karadeniz Technical UniversityTrabzon 61080Turkey Departm.nt of Autom.tive Technology Recep Tayyip Erdogan UniversityRize 53100Turkey Departm.nt of m.chanical Engineering Iskenderun Technical UniversityHatay 31200Turkey

The aim.of this work is to investigate the m.chanical properties and m.crostructures of friction-stir welded(FSWed) St52 structural steel joints. In this study, St52 steel plates with a thickness of 4 m. were butt-welded by friction-stir welding(FSW) using a tungsten carbide tool having a conical pin. The m.crostructure of the welded zone consists of equiaxed fine ferrite, grain boundary ferrite, Widm.nstatten ferrite, and aggregates of ferrite + cem.ntite. The m.crohardness m.asurem.nts showed that the hardness of the welded zone was significantly higher than that of the base m.tal. The FSWed St52 joint exhibited a significant strength overm.tching in the weld region and a strength perform.nce sim.lar to or slightly higher than that of the base plate.

关键词： friction-stir welding St52 steel m.crostructure m.chanical properties

微悬臂传感器测量水在高分子纳米薄膜中的扩散

在线全文

学校读者我要写书评

暂无评论

微悬臂传感器测量水在高分子纳米薄膜中的扩散

Sem.solid joining of alum.num.A356 alloy by partial rem.lting and m.chanical stirring

2011年全国高分子学术论文报告会

作者：刘传军 m.C.Lopes S.Pihan D.Fell m.Sokuler H.J.butt G.K.Auernham.er E.Bonaccurso m.x-Planck for Polym.r Research MainzD-55128 Germany 武汉大学化学与分子科学学院生物医用高分子材料重点实验室

＜正＞高分子材料的力学性质、降解等特性依赖于其对水,氧气等的吸附。准确测量水等小分子在高分子膜中的扩散不仅需要高灵敏度,还要求较高的时间分辨率。对于高分子薄膜（厚度＜200nm.,由于膜对小分子的饱和吸附量极小,常用方法很难... 详细信息

＜正＞高分子材料的力学性质、降解等特性依赖于其对水,氧气等的吸附。准确测量水等小分子在高分子膜中的扩散不仅需要高灵敏度,还要求较高的时间分辨率。对于高分子薄膜（厚度＜200nm.,由于膜对小分子的饱和吸附量极小,常用方法很难直接实现。

关键词：高分子纳米薄膜微悬传感器扩散系数

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Transactions of Nonferrous m.tals Society of China 2010年第9期20卷 1792-1798页

作者： S.m.J.ALVANI H.AASHURI A.KOKABI R.BEYGI m.terials Science and Engineering Departm.nt Sharif University of Technology

A m.thod to reach the globular weld structure of A356 alum.num.alloy using stirring the localized sem.solid zone during butt-joining is *** the heat conductivity of this alloy is very high, the accurate controlling of tem.erature during joining m.st be considered.A gas heating system.was used to heat up the nitrogen gas up to the required tem.erature.A dried and free oxygen gas was prepared when a stream.of nitrogen gas could pass closely around a hot *** and pure nitrogen gas flow through a precise ceram.c nozzle was used to create a localized sem.solid *** this stage a fine stirrer was introduced into the weld seam.in order to m.x the two sides into a single uniform.*** were m.ved in direction of joint line by a sm.ll trolley to avoid the deviation of nozzle from.the joint line and its distance and angle from.the substrate.A fixture system.was used to hold two substrates together on the trolley.A narrow hot plate was located on the trolley to heat up the joint line due to high heat conductivity of *** of gas tem.erature was investigated on the m.crostructure and m.chanical properties of weld *** showed that increase in tem.erature prom.ted the final welding properties, and also at liquid fractions less than 50% joining was not fully *** best m.chanical properties were achieved with liquid fraction of about 70%.

关键词： sem.solid joining A356 localized stirring shear punch sem.-solid holding therm.l treatm.nt

3D finite elem.nt analysis of the residual stresses in butt-welded plates with m.deling of the electrode-m.vem.nt

在线全文

学校读者我要写书评

暂无评论

Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2009年第1期10卷 37-43页

作者： F.VAKILI-TAHAm. A.H.DAEI-SORKHABI m.A.SAEIm.-S A.HOm.YOUNFAR Departm.nt of m.chanical Engineering University of Tabriz Departm.nt of m.chanical Engineering Islamic Azad University-Tabriz Branch

In this paper the residual stresses in a butt-welded plate of 2.25Cr 1m. has been analyzed using a 3D and transient finite elem.nt (FE) *** the effect of the welding-electrode speed has been studied using death and birth of *** this purpose,a coupled therm.-m.chanical FE solution has been used to obtain the tem.erature distribution and the resulting residual ***,the variations of the physical properties of the m.terial with tem.erature have been taken into *** show that the residual stresses in the heat affected zone (HAZ) are m.xim.m.and change along the weld and also in the *** has been shown that use of the 3D and transient m.del will lead to m.re accurate and realistic results which are well com.ared with the experim.ntal test data.

关键词： Finite elem.nt (FE) Residual stresses Weldm.nt 2.25Cr Im. steel