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0IntroductionMagnesium alloys containing small amounts of alloyedelements such as aluminum, manganese, zinc, zirconium,etc., have strength equaling that of mild steels. They dis-play high strength to weight ratio making them materials ofchoice whenever weight reduction is important or when it isimperative to reduce inertial forces (for rapidly moving ma-chine parts). Magnesiumalloys also have good castability,excellent recyclability and price competitiveness. Thereforethey are more and more wi… 相似文献
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J. Rodriguez 《Science & Technology of Welding & Joining》2014,19(4):343-349
Friction stir welding parameters were developed for a 6 mm thick dissimilar butt joint made of mild steel and Ni based alloy 625. A composite W-Re/polycrystalline cubic born nitride tool was used to study the effect of tool offset (between 0 and 3·13 mm away from the alloy 625 plate) and rotational speed (between 250 and 350 rev min?1) on joint consolidation. When non-optimal parameters were used, macrovoids were observed at the advancing side and faying surface near the joint interface root. Defect free joints were obtained using 300 rev min?1, 100 mm min?1, tool offset of 1·63 mm, and axial force between 25 and 30 kN, under force controlled mode. 相似文献
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SONG Yonglun 《中国焊接》1997,(2)
0IntroductionRadiationisanimportantphenomenonofarcweldingprocess.Essentially,itreflectsthephysicalprocessesoccUrringinthearcregion.Ithasbeennotedthattheinformationconcerningthearcprocess,suchastemperature.componentsandtheirdistributions.canberealizedthroughtheobservationofradiationbyarcself-emissionl'.ZI.Therefore,moreknowledgeaboutthefeatUresoftheradiationisneededtoenhancetheunderstandingofti)eldingarc.Inthisarticle.somephenomenaofweldingarcradiation,suchaspossiblewavelengthrangeoftheradiat… 相似文献
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Copper plates ,brass plates and copper/brass plates were friction stir welded with various parameters. Experimental results show that the microstructure of the weld is characterized by its much finer grains as contrasted with the coarse grains of parent materials and the heat-affected zones are very narrow. The microhardness of the copper weld is a little higher than that of parent plate. The microhardness of brass weld is about 25% higher than that of parent material. The tensile strength of copper joints increases with increasing welding speed in the test range. The range of parameters to obtain good welds for copper is much wider than that for brass. When different materials were welded, the position of copper plate before welding affected the quality of FSW joints. If the copperplate was put on the advancing side of weld, the good quality of weld could be got under proper parameters. 相似文献
5.
Some features of welding arc radiation 总被引:1,自引:0,他引:1
SONG Yonglun 《中国焊接》1996,(2)
Somefeaturesofweldingarcradiation¥SONGYonglun(Prof.SouthChinaUniversityofTechnology,Guangzhou,510641,China)Abstract:Thisinves... 相似文献
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In this essay, we studied how heat input affected the microstructure, hardness, grain size and heat-affected zone (HAZ) dimension of WCX355 ultra-fine grain steel which was welded respectively by the ultra narrow-gap welding (UNGW) process and the overlaying process with CO2 as protective atmosphere and laser welding process. The experimental results show when the heat input changed from 1.65 kJ/cm to 5.93 kJ/cm, the width of its HAZ ranged from O. 6 mm to 2. 1 ram. The average grain size grew up from 2 ~ 5 pln of base metal to 20~70 um and found no obvious soften phenomenon in overheatedzone. The width of normalized zone was generally wide as 2/3 as that of the whole HAZ, and the grain size in this zone is smaller than that in base metal. Under the circumstance of equal heat input, the HAZ width of UNGW is narrower than that of the laser welding. 相似文献
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A new type of non-preheated hardfacing electrode was developed using H08A as the core and the coat contents including ferrotitaninm, ferrovanadium, graphite, rutile etc. The microstrnctures and properties of hardfacing metal were systematically researched. The results show the hardness of hardfacing metal increases with increasing of ferrotitanium, ferrovanadium, graphite in the coat, but the crack resistance and processing weldability become worse. The carbides formed by arc metallurgic reaction are uniformly dispersed in the matrix structure. The phases of hardfacing metal consist of α-Fe, γ-Fe, VC, TiC and Fe3 C.The carbides are compression aggregation of TiC and VC, and their appearances present irregular block. The matrix microstrncture of hardfacing metal is lath martensite. The hardfacing layers with better crack resistance and wearability are achieved and no visible cracks occur when using non-preheated electrode in continuous welding process. Hardness of hardfacing metal is more than 60HRC, and its relative wearability is five times of wearability of D667 electrode in abrasive wear test. 相似文献
9.
Laser welding of AZ61 magnesium-based alloys 总被引:1,自引:0,他引:1
Laser welding of AZ61 magnesium alloys was carried out using a CO2 laser welding experimental system. The welding properties of AZ61 sheets with different thickness were investigated. The effect of processing parameters including laser power, welding speed and protection gas flow was researched. The results show that laser power and welding speed have large effect on the weld width and joint dimensions. Protection gas flow has relatively slight effect on the weld width. The property test of three typical joints indicates that microhardness and tensile strength in weld zone are higher than that of AZ61 base metal, Joints with good appearance and excellent mechanical properties can be produced using CO2 laser welding method. The microstructure with small grains in weld zone is believed to be respoasible for the excellent mechanical properties of AZ61 joints. 相似文献
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1 Introduction It is well known that high effeciency and high quality welding is the developing target of welding technology[1, 2]. TIG welding is one of the high quality and widely applied welding methods because its arc is stable, its precess is easy t… 相似文献
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Finite element method was adopted to investigate the temperature profile during ultrasonic welding of PEEK (polyetheretherketone ). The comparison of temperature fields was made among the triangular, semicircular and rectangular energy directors. The results show that the highest temperature appears on the sample surfaces in the welding interface. For triangular and semicircular energy directors, the gradient of their temperature fields become larger with welding amplitude increasing, and the temperature decreases along the normal line of surface. The melting point can be rapidly reached before large scale plastic deformation occurs as welding amplitude exceeds 25 μm for triangular energy and 35 μm for semicircular energy director. But for the rectangular energy director, its temperature field is dispersed even under 35μm welding amplitude. 相似文献
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A model was developed to simulate the temperature distribution and nugget formation during resistance spot welding ( RS1V) of zinc-coated steels. It employs a coupled thermal-electrical-mechanical analysis simulating the dynamic RSW process. Temperature-dependent thermal-electrical-mechanical material properties were considered including contact-resistance. The contact area was determined from a coupled thermal-mechanical analysis. A layer of transition elements was used to represent the change of contact area by killing or activating elements. The heat generation and temperature field were computed in a coupled thermal-electrical model. All these analyses were solved using the commercial finite element method (FEM) based on ANSYS code, and some advanced functions were used by writing a paragraph of codes by the authors. Compared with the results from only coupled thermal-electrical model in which contact area was uniform during the whole process, the result matches better to the experimental results. 相似文献
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Temperature field simulation of laser-TIG hybrid welding 总被引:1,自引:0,他引:1
The three-dimensional transient temperature distribution of laser-TlG hybrid welding was analyzed and simulated numerically. Calculations were based on a finite element model, in which the physical process of hybrid welding was studied and the coupling effect of the laser and arc in the hybrid process was fully considered. The temperature fields and weld crosssections of the typical welding parameters are obtained using present model. The calculation results shou that the model can indicate the relationship of energy match between laser and arc to joints cross-sections objectively, and the simulation results are well agreed with the experimental results. 相似文献
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《Science & Technology of Welding & Joining》2013,18(8):738-759
AbstractFriction welding is now well established as a means of joining many different types of materials, because it has proved itself to be a reliable and economical way of producing high quality welds. The present paper introduces different friction welding processes, their advantages and shortcomings. The history of friction welding and typical applications are also reviewed. In the context of friction welding, a number of subjects, such as frictional behaviour, joining mechanism, interface temperature and heat generation, still exist, where different concepts for explanation of the physical mechanisms have been proposed by different investigators. To clarify some inconsistencies in the interpretation of the friction welding process, a thorough review and critical assessment of the literature associated with this process is attempted. 相似文献
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《Science & Technology of Welding & Joining》2013,18(6):672-680
AbstractElectron beam welding is a well known process used where high precision, high reliability welds are needed, often in exotic materials. Recently, it has been proposed to apply the electron beam produced in a standard scanning electron microscope (SEM), with reversible modifications to increase beam current, for microscale welding. In addition to providing the clean environment associated with the column vacuum, the SEM in imaging mode provides exceptional capabilities in visualising extremely small parts. Furthermore, the standard stage and beam motion controls offer the possibility of flexible programming of beam path with relatively minor software additions. In order to better evaluate the requirements for and effects of μE-beam welding (μEBW) on typical microtechnologically important materials, a clear understanding of the characteristics of the SEM's beam and its interaction with possible target materials is needed. The penetration ability of electrons depends strongly upon their accelerating voltage and the target they are being directed at. Hence, in some circumstances the beam may interact as a surface heat source, while in others it may act as a volume heat source, with important consequences on weld schedule development for the parts and geometry being welded. In this work, the authors explore some of the factors involved and propose simple models for the electron beam heat source which depend on the parameters being used. 相似文献
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Based on the phase space reconstruction of welding current in short-circuiting transfer arc welding under carbon dioxide, the approximate entropy of welding current and its standard deviation have been calculated and analyzed at different welding speeds and different electrode extensions respectively. The experimental and calculated results show that at a certain arc voltage, wire feeding rate and gas flow rate, welding speed and electrode extension have significant effects not only on the approximate entropy of welding current, but also on the stability of welding process. Further analysis proves that when the welding speed and electrode extension are in an appropriate range respectively, the welding current approximate entropy attains maximum and its standard deviation minimum. Just under such circumstances, the welding process is in the most stable state. 相似文献
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Effect of welding current on strength and microstructure in resistance spot welding of AZ31 Mg alloy
In this paper, resistance spot welding were performed on lmm-thickness magnesium AZ31B plates. The effect of welding current on the microstructure and tensile shear force was investigated. It was found that the welding current governed the nugget growth, and the nugget could not form if current levels were insufficient. The nugget revealed a homogeneous, equiaxed, fine-grained structure, which consisted of non-equilibrium microstructure of α-phase dendrites surrounded by eutectic mixtures of α and β( Mg17All2 ) in the grain boundaries. With increasing welding current, the size of grains in nugget would be more smaller and uniform, and the width of plastic rings would be larger. Tensile shear tests showed that tensile shear force of the joints increased with increasing welding current when the welding current was smaller than 17 000 A. The maximum tensile shear force was up to 1980 N. 相似文献
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This paper presents a flexible method for the representation of welded seam based on spline interpolation. In this method, the tool path of welding robot can be generated automatically from a 3D CAD model. This technique has been implemented and demonstrated in the FANUC Arc Welding Robot Workstation. According to the method, a software system is developed using VBA of SolidWorks 2006. It offers an interface between SolidWorks and ROBOGUIDE, the off-line programming software of FANUC robot. It combines the strong modeling function of the former and the simulating function of the latter. It also has the capability of with on-line robot. The result data have shown its high accuracy and strong reliability in experiments. This method will improve the intelligence and the flexibility of the welding robot workstation. 相似文献
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A three-dimensional simulation model for the plasma-MIG welding process, which takes the interaction between the plasma arc and MIG arc into account, is presented and the quasi-steady temperature fields on the workpiece are calculated with the model. The 10 mm-5A06 aluminum alloy is welded and the temperature fields are measured with the thermoelectric couple. The simulation results and measured results show that the biggest deviation of peak temperature between them is below 20 ℃, which indicates good coincidence between the simulation and measurement. 相似文献