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1
Stewart, Jeffrey. "Temper Bead Welding for Dissimilar Metal Welds and Overlays." The Ohio State University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=osu1574840746589766.
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Xu, Lei. "Controlling interfacial reaction in aluminium to steel dissimilar metal welding." Thesis, University of Manchester, 2016. https://www.research.manchester.ac.uk/portal/en/theses/controlling-interfacial-reaction-in-aluminium-to-steel-dissimilar-metal-welding(721d3009-de49-434c-bd81-b01ff5973706).html.
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Two different aluminium alloys, AA6111 (Al-Mg-Si) and AA7055 (Al-Mg-Zn), were chosen as the aluminium alloys to be welded with DC04, and two welding methods (USW and FSSW) were selected to prepare the welds. Selected pre-welded joints were then annealed at T=400 - 570oC for different times. Kinetics growth data was collected from the microstructure results, and the growth behaviour of the IMC layer was found to fit the parabolic growth law. A grain growth model was built to predict the grain size as a function of annealing time. A double-IMC phase diffusion model was applied, together with grain growth model, to predict the thickness of each phase as a function of annealing time in the diffusion process during heat treatment. In both material combinations and with both welding processes a similar sequence of IMC phase formation was observed during the solid state welding. η-Fe2Al5 was found to be the first IMC phase to nucleate. The IMC islands then spread to form a continuous layer in both material combinations. With longer welding times a second IMC phase, θ-FeAl3, was seen to develop on the aluminium side of the joints. Higher fracture energy was received in the DC04-AA6111 joints than in the DC04-AA7055 joints. Two reasons were claimed according to the microstructure in the two joints. The thicker IMC layers were observed in the DC04-AA7055 joints either before or after heat treatment, due to the faster growth rate of the θ phase. In addition, pores were left in the aluminium side near the interface as a result of the low melting point of AA7055.The modelling results for both the diffusion model and grain growth model fitted very well with the data from the static heat treatment. Grain growth occurred in both phases in the heat treatment significantly, and was found to affect the calculated activation energy by the grain boundary diffusion. At lower temperatures in the phases with a smaller grain size, the grain boundary diffusion had a more significant influence on the growth rate of the IMC phases. The activation energies for the grain boundary diffusion and lattice diffusion were calculated as 240 kJ/mol and 120 kJ/mol for the η phase, and 220 kJ/mol and 110 kJ/mol for the θ phase, respectively. The model was invalid for the growth of the discontinuous IMC layers in USW process. The diffusion model only worked for 1-Dimensional growth of a continuous layer, which was the growth behaviour of the IMC layer during heat treatment. However, due to the highly transient conditions in USW process, the IMC phases were not continuous and uniform even after a welding time of 2 seconds. Therefore, the growth of the island shaped IMC particles in USW was difficult to be predicted, unless the nucleation stage was taken into consideration.
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Zhang, kaiwen. "Experimental and Computational Investigation of Temper Bead Welding and Dissimilar Metal Welding for Nuclear Structures Repair." The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1469036863.
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Sorensen, Daniel David. "Dissimilar Metal Joining in the Medical Device Industry." The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1494157928729494.
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Lee, Genevieve W. "Advanced Characterization of Solid-State Dissimilar Material Joints." The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1492794418438023.
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Wang, Yin. "A metallurgical approach for controlling interfacial reaction in aluminium to magnesium dissimilar metal welding." Thesis, University of Manchester, 2016. https://www.research.manchester.ac.uk/portal/en/theses/a-metallurgical-approach-for-controlling-interfacial-reaction-in-aluminium-to-magnesium-dissimilar-metal-welding(baf9186c-449e-44f3-9a1e-20dfde48b966).html.
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Dissimilar welding of Al to Mg alloys could potentially find significant application in the automobile industry, if the massive production of brittle intermetallic compounds (IMCs) at the joint interface can be prevented. In order to better understand Al-Mg IMC reactions, a comprehensive investigation of the interfacial region in AA6111 - AZ31 diffusion couples was carried out in this research. Three Al-Mg binary IMCs, namely the -Al12Mg17, -AlMg and -Al3Mg2 phases, were observed to form in the Al - Mg diffusion couple. In both the Al3Mg2 and Al12Mg17 layers, residual stresses were detected. The stress components normal to the joint interface were found to be positive, which had the effect of promoting the extension of lateral cracks; while the horizontal components were compressive, which could hinder cracking in the vertical direction. As a result, the fracture resistance of the two IMCs were asymmetric with lower values along the interface than in the vertical direction. The higher stress level in the Al3Mg2 layer made it more susceptible to lateral cracking and hence becoming the weak link in the Al - Mg dissimilar joints. A potential metallurgical solution has been explored involving the introduction of Zn into the material system, so that a new intermetallic compound with better properties can be formed to replace the unfavored Al3Mg2 phase. In this research, an Al-Zn coating alloy was proposed for this purpose. To determine the optimum composition for the alloy, a numerical method that combined CALPHAD thermodynamic calculation and diffusion simulations was developed. The modelling results indicated that Al-20 at. % Zn was the optimum composition for completely suppressing the formation of Al3Mg2, and this has been verified by static diffusion and friction stir spot welding (FSSW) experiments. In both cases, the designed coating alloy was effective in changing the Al-Mg reaction path by forming the mechanically superior (Al,Zn)49Mg32 phase as a substitute for Al3Mg2. The FSS welds prepared with the Zn containing coating alloy exhibited a 6 % increase in lap shear strength, compared to the conventional Al-Mg welds. This lower than expected improvement resulted from the Zn addition reducing the liquation temperature of the material system, resulting in the production of a detrimental eutectic mixture which facilitated debonding of the welds. As a potential alternative solution, Al-Si coating material has been proposed to inhibit the growth of Al-Mg IMC layers, in which the Si phase was expected to form a partial interdiffusion barrier between the substrate materials and change the reaction path by preferentially reacting with Mg. Comparison of long-term static diffusion experiments between the Al-Si coated and Al - Mg dissimilar joints showed that the nucleation and growth of Mg2Si could change the reaction path and greatly reduce the thickness of the Al-Mg IMC layer at the joint interface. Although in actual friction stir spot welding (FSSW), Mg2Si was not formed in a detectable amounts, due to the very short reaction time, the Al-Si coating still led to a significant reduction in the IMC thickness by partially blocking the Al-Mg interdiffusion process. With the coating applied, the Al - Mg dissimilar welds exhibited enhanced mechanical performance with both their strength and fracture energy being markedly increased, through a reduction in the IMC layer thickness and the presence of Si particle toughening the reaction layer by causing crack deflection.
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Liu, Bert C. Liu. "Joining Dissimilar Structural Alloys by Vaporizing Foil Actuator Welding: Process Conditions, Microstructure, Corrosion, and Strength." The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1471629967.
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Daniels, Thomas W. "APPLICABILITY OF COLD METAL TRANSFER FOR REPAIR OF DISSIMILAR METAL WELDS IN STAINLESS STEEL PIPING IN NUCLEAR POWER PLANTS." The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1429873704.
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Wolcott, Paul Joseph. "Ultrasonic Additive Manufacturing: Weld Optimization for Aluminum 6061, Development of Scarf Joints for Aluminum Sheet Metal, and Joining of High Strength Metals." The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1449162671.
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Siemssen, Brandon Raymond. "Development and Characterization of Friction Bit Joining: A New Solid State Spot Joining Technology Applied to Dissimilar Al/Steel Joints." Diss., CLICK HERE for online access, 2008. http://contentdm.lib.byu.edu/ETD/image/etd2425.pdf.
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Kapil, Angshuman. "Aspects of Vaporizing Foil Actuator Welding for Practical Automotive Applications." The Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu160579631346214.
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Suma, Emeric Emmanuel. "Using Duplex Stainless Steel to Join X65 Pipe Internally Clad with Alloy 625 for Subsea Applications." The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1492696298842902.
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Sowards, Jeffrey William. "Development of a chromium-free consumable for joining stainless steel." Columbus, Ohio : Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1237845645.
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Joesbury, Adam Michael. "New approaches to composite metal joining." Thesis, Cranfield University, 2015. http://dspace.lib.cranfield.ac.uk/handle/1826/10009.
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This thesis explores new methods for achieving load-carrying joints between the dissimilar materials of continuous fibre reinforced polymer matrix composites and structural metals. The new composite-to-metal joining methods investigated in this work exploit the metal-to-metal joining techniques of arc micro-welding, resistance spot welding, and metal filler brazing, to form novel micro-architectured metal adherends that can be used for enhanced composite-to-metal joining. Through a combination of equipment instrumentation and metallographic inspection of fabricated prototype joints, understanding is gained of how materials respond when processed by manufacturing techniques that have not previously been exploited for dissimilar material joining. Mechanical testing of prototype joints; both to ultimate loading strength and partial failure states, with subsequent inspection of specimens and comparative performances evaluation enabled joining performance characterisation of the new joining methods. Key results include: the identification of micropin reinforced adhesive joints to exhibit pseudo-ductile failure characteristics, resistance spot weld reinforcement of adhesive joints to boost bonding performance, and the use of a polymer infused metal foam to overcome difficulties of thermoplastic to metal adhesion. Through this work knowledge of how novel micro-architectures reacted under mechanical loading enabled insights to be gained into how perceived manufacturing defects can benefit joining performance. Such examples include, localised material weakness that lead to global pseudo-ductile failure behaviour, and low-strength secondary joining mechanisms boosting primary load transfer systems. By comparison of the diverse joining methods investigated in this work, trends were identified that suggest joining performance between the two dissimilar materials is improved by increasing the direct interaction between the composite reinforcement fibres and the metal structure. It is demonstrated that joining improvements are gained by forming mechanical connections between metals and composite precursory material before the final manufacturing process of the composite.
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Bäck, Mimmi. "Welding of dissimilar metals in different welding positions." Thesis, KTH, Materialvetenskap, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-184241.
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The three boiling water reactors (BWR) in Oskarshamn produce about 10 % of the electrical power in Sweden. The combination of intense radiation fluxes and high temperatures in nuclear reactors creates an extraordinary environment. Therefore, a number of material challenges arise at a nuclear power plant that needs to be solved in order to maintain the nuclear power production, safety and reliability. Dissimilar metal welds can be found at a lot of places in nuclear power plants and due to reparations or replacement some dissimilar metal welds need to be welded on site. The technical regulations for the Swedish nuclear power plants specifies that welding of dissimilar joints shall be made with gap of at least 1.5 mm and in horizontal position. Welding a dissimilar joint on site makes it difficult to follow the technical regulations, therefore, the aim with this study is to determine if different welding positions of dissimilar metal welds affect the structure and composition of the weld metal in a negative way and to investigate the importance of a gap in the root. In this study six samples were welded in three different welding positions, horizontal, vertical and reversed vertical with or without a gap of 1.5 mm in the root. The samples were evaluated by non-destructive testing, optical microscopy, chemical analysis, tensile testing, bend testing and hardness measurements. The results shows that two of the samples welded without gap failed the transverse root bend test, the same samples did also have high hardness values in the root bead. The conclusions are that the welding position, horizontal, vertical or reversed vertical does not affect the weld negative in a noticeable way. However, the gap and a good dilution with the filler metal are important.
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Wang, Tianhao. "Friction Stir Welding of Dissimilar Metals." Thesis, University of North Texas, 2018. https://digital.library.unt.edu/ark:/67531/metadc1404577/.
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Dissimilar metals joining have been used in many industry fields for various applications due to their technique and beneficial advantages, such as aluminum-steel and magnesium-steel joints for reducing automobile weight, aluminum-copper joint for reducing material cost in electrical components, steel-copper joints for usage in nuclear power plant, etc. The challenges in achieving dissimilar joints are as below. (1) Big difference in physical properties such as melting point and coefficient of thermal expansion led to residual stress and defects. (2) The miscibility issues resulted in either brittle intermetallic compound layer at the welded interface for miscible combinations (such as, aluminum-steel, aluminum-copper, aluminum-titanium, etc.) or no metallurgical bonding for immiscible combinations (such as magnesium-copper, steel-copper, etc.). For metallurgical miscible combinations, brittle intermetallic compounds formed at the welded interface created the crack initiation and propagation path during deformational tests. (3) Stress concentration appeared at the welded interface region during tensile testing due to mismatch in elastic properties of dissimilar materials. In this study, different combinations of dissimilar metals were joined with friction stir welding. Lap welding of 6022-T4 aluminum alloy/galvanized mild steel sheets and 6022-T4 aluminum alloy/DP600 steel sheets were achieved via friction stir scribe technology. The interlocking feature determining the fracture mode and join strength was optimized. Reaction layer (intermetallic compounds layer) between the dissimilar metals were investigated. Butt welding of 5083-H116 aluminum alloy/HSLA-65 steel, 2024-T4 aluminum alloy/316 stainless steel, AZ31/316 stainless steel, WE43/316 stainless steel and 110 copper/316 stainless steel were obtained by friction stir welding. The critical issues in dissimilar metals butt joining were summarized and analyzed in this study including IMC and stress concentration.
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Ratanathavorn, Wallop. "Development and evaluation of hybrid joining for metals to polymers using friction stir welding." Licentiate thesis, KTH, Industriell produktion, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-173232.
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Combinations of different materials are increasingly used in the modern engineering structures. The driving forces of this trend are rising fuel costs, global warming, customer demands and strict emission standards. Engineers and industries are forced to improve fuel economy and cut emissions by introducing newly design engines and lightweighting of structural components. The use of lightweight materials in the structures has proved successful to solve these problems in many industries especially automobile and aerospace. However, industry still lacks knowledge how to manufacture components from polymeric materials in combination with metals where significant differences exist in properties. This thesis aims to demonstrate and generate the methodology and guidelines for hybrid joining of aluminium alloys to thermoplastics using friction stir welding. The developed technique was identified, optimized and evaluated from experimental data, metallography and mechanical characterization. The success of the technique is assessed by benchmarking with recent literatures. In this work, lap joints between aluminium alloys (AA5754, AA6111) and thermoplastics (PP, PPS) were produced by the friction stir welding technique. The specimens were joined with the friction stir welding tools under as-received conditions. Metallic chips were generated and merged with the molten thermoplastic to form a joint under the influence of the rotating and translating tool. The effects of process parameters such as rotational speed, translational speed and distance to backing were analyzed and discussed. The investigation found joint strength was dominated by mechanical interlocking between the stir zone and the aluminium sheet. The results also show that the joint strength is of the same order of magnitude as for other alternative joining techniques in the literature.QC 20150908
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Soundararajan, Vijay. "Thermo-mechanical and microstructural issues in joining similar and dissimilar metals by friction stir welding." Ann Arbor, Mich. : ProQuest, 2007. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3245931.
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Thesis (Ph.D. in Mechanical Engineering)--S.M.U., 2007.Title from PDF title page (viewed Mar. 18, 2008). Source: Dissertation Abstracts International, Volume: 67-12, Section: B, page: 7339. Adviser: Radovan Kovacevic. Includes bibliographical references.
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Lu, Ying. "Resistance and Ultrasonic Spot Welding of Light-Weight Metals." The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1533730654738672.
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Atwood, Lorne Steele. "Friction Bit Joining of Dissimilar Combinations of GADP 1180 Steel and AA 7085 – T76 Aluminum." BYU ScholarsArchive, 2016. https://scholarsarchive.byu.edu/etd/6400.
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Friction Bit Joining (FBJ) is a method used to join lightweight metals to advanced high-strength steels (AHSS). The automotive industry is experiencing pressure to improve fuel efficiency in their vehicles. The use of AHSS and aluminum will reduce vehicle weight which will assist in reducing fuel consumption. Previous research achieved joint strengths well above that which was required in three out of the four standard joint strength tests using DP980 AHSS and 7075 aluminum. The joints were mechanically tested and passed the lap-shear tension, cross-tension, and fatigue cycling tests. The t-peel test configuration never passed the minimum requirements. The purpose of continuing research was to increase the joint strength using FBJ to join the aluminum and AHSS the automotive industry desires to use specifically in the t-peel test. In this study FBJ was used to join 7085 aluminum and GADP1180 AHSS. The galvanic coating on the AHSS and its increased strength with the different aluminum alloy required that all the tests be re-evaluated and proven to pass the standard tests. FBJ is a two-step process that uses a consumable bit. In the first step the welding machine spins the bit to cut through the aluminum, and the second step applies pressure to the bit as it comes in contact with the AHSS to create a friction weld.
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Squires, Lile P. "Friction Bit Joining of Dissimilar Combinations of Advanced High-Strength Steel and Aluminum Alloys." BYU ScholarsArchive, 2014. https://scholarsarchive.byu.edu/etd/4104.
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Friction bit joining (FBJ) is a new method that enables lightweight metal to be joined to advanced high-strength steels. Weight reduction through the use of advanced high-strength materials is necessary in the automotive industry, as well as other markets, where weight savings are increasingly emphasized in pursuit of fuel efficiency. The purpose of this research is twofold: (1) to understand the influence that process parameters such as bit design, material type and machine commands have on the consistency and strength of friction bit joints in dissimilar metal alloys; and (2) to pioneer machine and bit configurations that would aid commercial, automated application of the system. Rotary broaching was established as an effective bit production method, pointing towards cold heading and other forming methods in commercial production. Bit hardness equal to the base material was found to be highly critical for strong welds. Bit geometry was found to contribute significantly as well, with weld strength increasing with larger bit shaft diameter. Solid bit heads are also desirable from both a metallurgical and industry standpoint. Cutting features are necessary for flat welds and allow multiple material types to be joined to advanced high-strength steel. Parameters for driving the bit were established and relationships identified. Greater surface area of contact between the bit and the driver was shown to aid in weld consistency. Microstructure changes resulting from the weld process were characterized and showed a transition zone between the bit head and the bit shaft where bit hardness was significantly increased. This zone is frequently the location of fracture modes. Fatigue testing showed the ability of FBJ to resist constant stress cycles, with the joined aluminum failing prior to the FBJ fusion bond in all cases. Corrosion testing established the use of adhesive to be an effective method for reducing galvanic corrosion and also for protecting the weld from oxidation reactions.
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Weickum, Britney. "Friction Bit Joining of 5754 Aluminum to DP980 Ultra-High Strength Steel: A Feasibility Study." BYU ScholarsArchive, 2011. https://scholarsarchive.byu.edu/etd/2789.
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In this study, the dissimilar metals 5754 aluminum and DP980 ultra-high strength steel were joined using the friction bit joining (FBJ) process. The friction bits were made using one of three steels: 4140, 4340, or H13. Experiments were performed in lap shear, T-peel, and cross tension configurations, with the 0.070" thick 5754 aluminum alloy as the top layer through which the friction bit cut, and the 0.065" thick DP980 as the bottom layer to which the friction bit welded. All experiments were performed using a computer controlled welding machine that was purpose-built and provided by MegaStir Technologies. Through a series of designed experiments (DOE), weld processing parameters were varied and controlled to determine which parameters had a significant effect on weld strength at a 95% confidence level. The parameters that were varied included spindle rotational speeds, Z-command depths, Z-velocity plunge rates, dwell times, and friction bit geometry. Maximum lap shear weld strengths were calculated to be 1425.4lbf and were to be obtained using a bit tip length at 0.175", tip diameter at 0.245", neck diameter at 0.198", cutting and welding z-velocities at 2.6"/min, cutting and welding RPMs at 550 and 2160 respectively, cutting and welding z-commands at -0.07" and -0.12" respectively, cooling dwell at 500 ms, and welding dwell at 1133.8 ms. These parameters were further refined to reduce the weld creation time to 1.66 seconds. These parameters also worked well in conjunction with an adhesive to form weld bonded samples. The uncured adhesive had no effect on the lap shear strengths of the samples. Using the parameters described above, it was discovered that cross tension and T-peel samples suffered from shearing within the bit that caused the samples to break underneath the flange of the bit during testing. Visual inspection of sectioned welds indicated the presence of cracking and void zones within the bit.
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Henon-Vernet, Christine. "Contribution à l'étude métallurgique d'une liaison bimétallique soudée 16MND5/309/308." Grenoble INPG, 1997. http://www.theses.fr/1997INPG0021.
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Les liaisons bimetalliques soudees concernees par cette etude interessent les assemblages par soudage des tubulures de cuve en acier faiblement allie 16mnd5 et des tuyauteries en acier austenitique 316 du circuit rep. Certaines de ces liaisons presentent en peau externe des defauts intergranulaires en premiere couche de beurrage qui n'apparaissent que lorsque la structure de cette premiere couche est purement austenitique. Les materiaux assembles ayant des coefficients de dilatation tres differents, nous avons suppose que la fatigue thermique pouvait etre responsable de la presence de ces defauts. Aussi, afin de tester cette hypothese et estimer le degre de nocivite de la structure austenitique, nous avons etudie une liaison bimetallique presentant une structure austenitique en premiere couche et avons simule la fatigue thermique par de la fatigue oligocyclique a 320c. Nous nous sommes attaches a decrire les transformations metallurgiques induites par le caractere heterogene de l'assemblage. De nombreuses discontinuites ont ainsi pu etre mises en evidence au niveau de l'interface metal de base/premiere couche de beurrage : discontinuites chimiques, microstructurales et cristallographiques. Une analyse des conditions de solidification imposees par le caractere heterogene de la liaison a ete proposee permettant de rendre compte des phenomenes observes. D'un point de vue mecanique, il semble que ces heterogeneites aient peu d'influence sur la tenue en fatigue de la liaison. Quel que soit le mode de sollicitation envisage, nous ne recreons pas les decohesions intergranulaires observees sur site. Une modelisation par elements finis a ete menee pour determiner la repartition de la deformation plastique cumulee et expliquer la presence d'une zone sans bandes de glissements apparentes au niveau de l'interface, cote beurrage.
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Bhat, K. Udaya. "Studies On Dissimilar Metal Welding." Thesis, 2008. http://hdl.handle.net/2005/786.
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The area of research dealing with joining of dissimilar metals has been active in recent time. Although fusion and non-fusion techniques of joining have been effectively used for manufacturing components, a comprehensive scientific understanding of the process is lacking. This void exists both in fusion and non-fusion welding methods. The present investigation addresses some of these aspects. The investigation consists of two sections - Part A and Part B. Part A is on Friction welding and Part B deals with Fusion welding using laser. Each section has two chapters each.
Following an introductory chapter, basic aspects of friction welding is presented in chapter 2. Chapter 3 deals with the work on friction welding of Fe-Cu couple. Fe-Cu couple is a system with positive heat of mixing. After a brief introduction on various non-equilibrium processes that can occur in this system, experimental details and results are presented. Using the results an attempt is made to understand the flash formation, formation of pores at the interface and the formation of chemically altered zone. It is observed that a chemically altered layer forms predominantly on the Cu side of the interface. It consists of Fe entrapped as fragments/fine crystals and as solid solution in Cu matrix. This zone has higher thickness at the edges than at the center. The mechanism of formation of this interfacial layer which is central to the joining process is related to the fracture and transport of fragments during plastic deformation. Fe forms solid solution in copper under non-equilibrium conditions promoted by shear energy. Using the concept of ballistic mixing, the formation of solid solution is explored. Using nano-indentation experiments mechanical properties of the weldment is estimated and an attempt is made to correlate mechanical properties with the amount of second element present in that location.
The chapter 4 in part A deals with the friction welding of Ni-Ti couple. Ni-Ti system has negative heat of mixing and it forms a number of intermetallics. After a brief introduction to the chapter, various experimental techniques and strategies followed to carry out the experiments are explained. Following these, the results are presented. It is observed that TiNi3 formed at initial stage. Theories based on effective heat of formation and surface energy also predict the nucleation of TiNi3. With the continuation of frictional processes, the formation of TiNi and Ti2Ni phases were also observed. Formation of Ti2Ni was shown to greatly accelerate due to shear process. In this system two complementary processes like ballistic mixing and thermal assisted diffusion accelerate Ti2Ni formation. From mechanical tests it is found that Ti2Ni layer in the weldment is weak and hence formation of Ti2Ni in the weldment is detrimental.
In chapter 5 an introduction to fusion welding of dissimilar metals is presented as background materials for the subsequent chapters. Chapter 6 deals with nature of segregation of Ag during laser welding of Fe-Ni couple. Ag is used as a tracer to probe fluid flow in the Fe-Ni couple during laser welding. Ag is immiscible both in Fe and Ni whereas Fe and Ni form a complete solution at an elevated temperature and in liquid state. Besides the experimental work, numerical simulation of the weld pool were carried out using homogeneous mixture model using SIMPLER algorithm. Experiments and simulations indicate that fluid flow is asymmetrical and in the deep penetration welding strong convection in the pool drives the tracer to the top of the pool. Overall distribution of the tracer is due to the combined effect of convection and diffusion. In shallow welding there exists a boundary region where tracer does not penetrate.
In chapter 7 the results of instrumented indentation experiments on laser welded Fe-Cu weldment has been presented. It was earlier reported that during laser welding of Fe-Cu couple, a variety of microstructures evolves at various locations in the weldment and hardness of the weldment were found to be very high. Here an attempt has been made to explore in details the origin of such a high hardness. The chapter starts with a description of various microstructures that are observed in this weldment followed by the various procedures used for extracting data from instrumented indentation tests. It is followed by the presentation of the experimental results. It is found that rule of mixture along with Hall-Petch strengthening explains the observed increase in hardness of the weldment. The fine scale microstructure consisting of alternate Fe rich and Cu rich layers increases the hardness of the weldment. On copper side of the weldment, composition and scale of microstructure fluctuates and so also the hardness. Finally in chapter 8 overall conclusions of the various chapters in the thesis have been summarised.
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Tang, Zih-yong, and 唐自勇. "The Study of Dissimilar Metal Welding and Post-Welding." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/65599259365328199292.
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碩士國立交通大學
機械工程學系
99
The article was investigated on the A2024 and A7050 dissimilar welding and it’s mechanical properties for post-weld heat treatment process. In this experiment, tungsten inert gas (TIG) welding process was utilized to make weldments with filler metals of ER2319 and ER5356. The effect of heat treatment of natural aging (T1), solution treatment(T4), and solution treatment plus artificial aging(T6) on the weldment were investigated. The tensile test, microhardness test, and optical microscope were used to study the mechanical properties and microstructures the effect of different trace elements on the material mechanical properties and microstructure is also determined. After T4 or T6 heat treatment, multiple precipitates were found in heat affected zone(HAZ) grain and grain boundaries. The microhardness, ultimate tensile strength, and yield strength of the heat treated weldment were greatly enhanced by the heat treatment. The fractured surface of T1 treatment shows dimple appearance indicating some ductility. In T6 treatment, some region maintain dimple surface, some region tend to brittleness cracking.
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Huang, Hung-Chau, and 黃鋐洲. "Characteristics of Dissimilar Metal Joints by Resistance Projection Welding." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/rf9s2r.
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碩士國立虎尾科技大學
材料科學與綠色能源工程研究所
99
In this study, austenitic stainless steel (SUS 304), ferrite stainless steel (SUS 430) and Kovar alloy sheets were resistance projection welded as lap joints. The process parameters were steel sheet combination in joints and test some important parameters as electrode material, charging voltage, operating pressure and projection height; on the nugget area and maximum tensile force of the welded joint were experimentally investigated. The results showed that increasing charging voltage increased heat input and therefore weld nugget growth. Also, high conductivity electrode material or increased operating pressure, nugget area could be improved significantly. If the selected charging voltage was too small, larger an electrode force was applied, caused premature mechanical collapse of the projection and thus decreased in tensile property. In 60V charging voltage, the heat input could not generate enough heat to cause melting and coalescence of the sheets forming a sound fusion joint. Fracture type was observed as crescent shape, larger area showed higher tensile force value. Vickers micro hardness results showed that the weld nugget hardness for all welding conditions did not show many differences
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Tsung-HsuanTsai and 蔡宗軒. "Design Analysis of Co-rotating Mechanism by Dissimilar Metal Screws Welding." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/zumt94.
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Jiang, Cong-Zheng, and 江聰政. "The study of friction stir welding in Cu/Al dissimilar metal." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/99907355698295917544.
Full textAbstract:
碩士國立中興大學
材料工程學系所
94
Copper alloy and Aluminum alloy are usually used in heat exchanger or heat sink. So, how to combine this two dissimilar metals join together has become a serious problem. Because those two metals have different fused junction characters, usually use solid phase process to join them together. For example, friction welding, explosion welding, supersonic frequency welding, brazing and soldering. But they also have some limitations, like friction welding and explosion welding have geometry limits, brazing and soldering used only particular materials. But friction stir welding can overcome all the problems above. Friction stir welding (FSW) is a kind of solid phase process, and it is new and promising welding process that can produce low-cost and high-quality joints of heat-treatable alloys. So for academe and in industry, FSW is important .This research use 1100 Al alloy and phosphorus bronze for base metal, discuss the butt joint’s characteristic of the two dissimilar metals.The resule shows that preformed dissimilar FSW of 1100 Al alloy and phosphorus bronze with 6 mm thickness, and it reported the weldability and mechanical properties of a dissimilar high-quality weld of Al and Cu alloys. It is shown that the material is transported by two processes. The first is a wiping of material from the advancing front side of the pin onto a zone of material that rotates and advances with the pin. The material undergoes a helical motion within the rotational zone that both rotates, advances, and descends in the wash of the threads on the pin and rises on the outer part of the rotational zone. After one or more rotations, this material is sloughed off in its wake of the pin, primarily on the advancing side. The second process is an entrainment of material from the front retreating side of the pin that fills in between the sloughed off pieces from the advancing side.
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Weng, San-Feng, and 翁三峰. "Studies on the Friction Stir Spot Welding of Dissimilar Metal Multilayer Sheets." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/wc9f8q.
Full textAbstract:
碩士國立中山大學
機械與機電工程學系研究所
107
The four metal sheets are spot lap welded using a fixed-load friction stir welding machine and an assembly embedded rod tool without the probe, where the shoulder is a tungsten carbide ring and the SS400 low carbon steel rod is embedded in its center. The four metal sheets are SS400 low carbon steel, C1100 pure copper, G3302 SGHC galvanized steel and AA6061-T6 aluminum alloy, where the aluminum alloy sheet has a thickness of 5 mm and the remaining sheet thickness is 2 mm. There are two types of sheets arranged in sequence, where the first kind is low carbon steel/galvanized steel/pure copper/aluminum alloy, and the second kind is low carbon steel/pure copper/Galvanized steel/aluminum alloy. Welding parameters include rotation speed of tool (600, 900, 1200 rpm) and downward force (6, 9, 12 kN). During the welding process, the downward force, the displacement of specimens and three interface temperatures are measured. After welded, the tensile strength of each joint surface is measured by a tensile-shear test, and the fractured surface is observed using an optical microscope. Results show that the rotation speed of tool for 600 rpm or 1200 rpm can avoid the resonance between the machine and the tool during the welding process. The rotation speed of tool above 900 rpm can avoid the sticking between the low carbon steel sheet and the embedded rod when the welding tool is retracted. Therefore, the best rotation speed of tool is 1200 rpm. The rate of interface temperature rise increases along with the rotation speed or downward force. Effect of the downward force on the maximum temperature of each interface is not significant. The joint can be successful at the downward force of 6 kN and 9 kN, and the tungsten carbide ring of the welding tool may be broken at 12 kN. Therefore, the best downward force is 9 kN. The rotation speed of tool 1200 rpm and the downward force 9 kN is the best welding parameter. In the first kind order, the low carbon steel sheet and the galvanized steel sheet cannot be jointed, and the other sheets can be jointed. In the second kind order, four sheets can be jointed. The joint strengths for low carbon steel/pure copper, pure copper/galvanized steel, and galvanized steel/aluminum alloy are 9 kN, 8 kN, and close to 10 kN, respectively.
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JING, HUNG YUAN, and 洪源璟. "Residual stress distribution after Overlay weld with Gas Tungsten Arc Welding of Dissimilar Metal." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/8m2247.
Full textAbstract:
碩士國立臺灣科技大學
機械工程系
106
This research involved weldment of dissimilar A508 low alloy steel and 316L stainless steel for base metal. The welding of dissimilar parts was conducted by use of gas tungsten arc welding (GTAW) and gas metal arc-welding (GMAW) techniques with nickel-based 82/182 alloys used as filler metal for butt joint and butter layer while inconel alloy 52M used for cladding. Observation of microstructure changes within the weldment and its were conducted for different settings of welding parameters and processes. The X-ray diffraction method was used to detect and analyze the axial residual stress on the dissimilar metal weld area and on the cladding layer of the weldment . Experimental results showed that thermal stress was generated during cooling of weldment due low thermal expansion coefficient of A508 base metal and high thermal expansion coefficient of 182 alloy and 316L base metal. Residual stresses therefore increased after cooling of welding due to presence of both compressive and tensile stresses. The thermal influence of the cladding layer can also significantly increase compressive stress at the weldment. The interface of the dissimilar metal weldment experienced tensile stresses due to difference in thermal expansion coefficient, and the residual stress. Thus, residual stress would increase further with increased difference of thermal expansion coefficients.
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Tsai, Yao-Long, and 蔡曜隆. "The Study on Welding Temperature and Residual Stress of S15C/SUS304 Dissimilar Metal Butt Joint." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/78217246054432536247.
Full textAbstract:
博士國立交通大學
機械工程學系
98
This study explored the difference in the distribution of the temperature and residual stresses of both the similar and dissimilar weld metal joints. Autogenous GTA welding process was conducted on stainless steel 304 and structural steels S15C. The hole-drilling method was used to experimentally measure the residual stress. The thermo-elastic-plastic theory was employed in the finite element model with temperature dependent material properties. The results showed that using 54% thermal efficiency of GTA welding can accurately simulate the welding temperature distributions. Under the same welding parameters, results showed that the maximum longitudinal tensile residual stresses increase linearly with the increase of the thermal expansion coefficient and the increase of the yield stress. The length of the tensile residual stress zone linearly decreases with the increase of the thermal conductivity. Finally, based on the relationship between material properties and welding residual stresses, a very useful and effective prediction equation is developed and verified in this study.
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Jin-Yuan, Wun, and 溫晉源. "Study on the Characteristics of Hot Cracking and Dissimilar Metal Welding on 2024 Aluminum Alloys." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/22727966929897842739.
Full textAbstract:
碩士國立臺灣師範大學
機電科技研究所
98
The main purpose of this study focuses on 2024 aluminum alloys. it includes two parts: The first part aims to investigate the hot cracking susceptibility of 2024 aluminum alloys. The specimens were experimented with tungsten Inert gas welding (TIG) at first under the condition of no filler metal used. Then, the spot varestraint testing was used to evaluate the effect resulting from the times of thermal cycles and augment strain over hot cracking susceptibility of 2024-T351 and 2024-T6 aluminum alloys. Meanwhile, the causes and patterns of hot cracking were observed and analyzed with Metallographic test and scanning electron microscope (SEM). The experimental result shows that the times of thermal cycles is irrelevant to hot cracking susceptibility in the weld fusion zone of 2024-T351 and 2024-T6. But the times of thermal cycles does affect hot cracking susceptibility in weld metal heat affected zone (W. M. HAZ) of both 2024-T351 and 2024-T6. As the times of thermal cycles increases, the length of hot cracks grows. Besides, the length of hot cracks in base metal heat affected zone (B. M. HAZ) of 2024-T351. However, this phenomenon does not appear in base metal heat affected zone (B. M. HAZ) of 2024-T6.on the other hand, as augment strain given increases, the total crack length (TCL) of these two materials both remains constant. With Metallographic test, the hot cracking occurrence was seen lying along the crystalline grain boundary in fusion zone and HAZ. Hot cracks yielded in fusion zone and in HAZ are categorized to solidification cracking and liquation one respectively. The types of hot cracking can be further identified with SEM. The second part focuses on the research over mechanical property of dissimilar metal welding with 2024-T351 and 7050-T7451 through metallography and tensile test. TIG was adopted. ER2319 and ER5356 serve as individual filler during welding. After welding, specimens were conducted with respectively different heat treatment, natural aging treatment (T1) and solution heat treatment (T4). The experimental result indicates: (1)The micro-hardness in fusion zone of dissimilar metal welding enormously after T4 is enormously bigger than that after T1. The difference can achieve 20 to 30 Hv. (2) The specimens using ER2319 as filler have higher ultimate tensile strength (UTS), yield strength (YS) and elongation (El) than those using ER5356 after T1. But the above-mentioned parameters of specimens with these two fillers show no difference after T4.
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Pereira, Diogo Jorge de Oliveira Andrade. "Developments in Magnetic Pulse Welding." Doctoral thesis, 2018. http://hdl.handle.net/10362/45649.
Full textAbstract:
Magnetic Pulse Welding is a solid state joining technology based on impact, which allows to produce overlap joints both in planar and tubular geometries. The technology has seen an increased interest in recent years, especially as a result of the industrial need to joint dissimilar materials (metallic and non-metallic) which easily form brittle intermetallic phases when welded by fusion-based processes.
However, no significant improvements on existing equipments have been reported, which are normally sized for endurance, compromising the machine efficiency. In fact these are normally equipped with large storage capacitors banks, which are sometimes insufficient for dissimilar material combinations that require more energy to weld
In this study existing equipments were analysed to understand the key components aiming at its optimization. A prototype machine was developed and assembled envisaging higher discharge energies efficiency. The equipment was tested and validated in tubular transitions due to the facility to produce the coils in laboratory facilities but also due to the industrial applications identified.
This joining process is known to need a conductive flyer material to allow inducing current for the magnetic interaction which projects the flyer against the target to produce a weld.
Thus, tube to tube and tube to rod welds were produced in AA6063 in similar and dissimilar metallic joints to Ti6A4V. AA7075 to carbon fibre reinforced polymer tubes transitions were also successfully produced especially when Cu or Ni ductile interlayers were used.
The developed prototype equipment was compared to a commercial machine to identify the optimization achieved and to compare characteristics of the welds produced. For this, the joints were characterized both structural and mechanically.
The prototype machine proved to have a higher efficiency needing less than 15% of the energy required on the commercial machine to produce similar aluminium transitions (reducing from 16 kJ to 2 kJ). The machine also proved to be efficient in producing dissimilar joints, such as aluminium to titanium transitions and metal to non-metal transitions.
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Chatterjee, Subhradeep. "Microstructure Development During Laser And Electron Beam Welding Of Ti/Ni Dissimilar Joints." Thesis, 2006. http://hdl.handle.net/2005/601.
Full textAbstract:
Fusion welding of dissimilar metals constitutes a crucial processing stage in a variety of applications, and the use of high energy beams (HEB) like lasers and electron beams for such welding applications has several advantages, such as, precision, narrow heat affected zone, and consequently, low distortion. An understanding of microstructural evolution in the weld is a prerequisite for producing sound joints with desired properties. HEB welding of similar metals have been studied extensively. In contrast, fewer studies have been directed toward understanding the fundamental aspects of solidification of dissimilar welds. This thesis presents an effort in that direction by exploring microstructural evolution in Ti/Ni dissimilar welds.
Welding of Ti/Ni serves to illustrate the fundamental differences that distinguish dissimilar welding from the welding of similar metals. These are: (i) Thermophysical properties of the base metals are, in general, different, and this can have important consequences in the heat transfer conditions. (ii) Composition can vary over an wide range, the extreme being for the case of a pure binary couple, and the solid–liquid interface cannot be defined by a single liquidus isotherm. (iii) In addition to the surface energy driven Marangoni convection, a strong solutal convection can arise due to a large difference in the density of the base metals. (iv) Nucleation of phases assumes greater importance, especially in systems with intermediate phases.
We have carried out laser and electron beam welding (LW and EBW) experiments in a butt welding geometry to join Ti/Ni dissimilar couples. Weld microstructures were characterised using scanning and transmission electron microscopy (SEM and TEM); composition information was obtained from energy dispersive spectroscopy (EDS) of Xrays in the SEM. In addition to the pure binary couple, we have also studied electron beam welding of Ti/Ni with a thin Ta interlayer. We summarise our findings in each set of experiments in the following sections.
Laser welding of Ti/Ni
We have studied partial penetration welds obtained within the range of experimental parameters used in our study. These welds show the following interesting features:
1. The welds are asymmetric with respect to the initial joint. Despite its higher melting point, Ti melts more than Ni due to its lower thermal diffusivity, making the average composition of the weld richer in Ti (Ti–40at.%Ni).
2. Composition changes very steeply near the fusion interfaces in both Ti and Ni with associated microstructural changes. The variation is of much lesser magnitude in the rest of the weld, reflecting a well mixed melt pool on a macroscopic scale.
3. Growth of base metal grains into the weld pool at the fusion interfaces is severely restricted at both Ti and Ni ends.
4. The Ti fusion interface is marked by a band consisting of Ti2Ni dendrites which grow toward the Ti base metal.
5. Layered structures form at the Ni fusion interface. The sequence of the layers is: solid solution (Ni)→ Ni3Ti→ Ni3Ti+NiTi eutectic → NiTi. We note the absence of the (Ni)+Ni3Ti eutectic in this sequence.
6. NiTi and Ti2Ni are the major phases that appear in the bulk of the weld. Volume fraction and morphology of NiTi vary almost periodically to form microstructural bands.
7. Solid state transformation of NiTi results in the formation of the Rphase and martensite, which reflect the composition heterogeneity in the weld. Sometimes, Ni4Ti3 precipitates are observed also, providing indirect evidence of nonequilibrium solidification.
8. Nitrogen pickup from the atmosphere during welding leads to the formation titanium nitride dendrites in the weld.
9. Solutal convection and buoyancy forces manifest themselves through the segregation of the lighter nitride and Ti2Ni phases toward the top surface of the weld; the heavier liquid forms blocky NiTi in the bottom half of the weld.
These observations stand in striking contrast with the microstructures of conventional welds. We have proposed a set of composition and temperature profiles in the weld which reflect the diffusive and advective transport processes; when combined with thermodynamic information from the Ti–Ni phase diagram to yield spatial liquidus temperature profiles, these profiles can adequately explain most of the results. Our observations illustrate the importance of (a) nucleation, and (b) the inhomogeneous nature of the melt in which growth takes place. They also highlight the role of convective currents in bringing about local fluctuations in composition and temperature leading to ‘low velocity bands’.
Electron beam welding of Ti/Ni
We have carried out full penetration EBW of thin plates of Ti and Ni. The major observations are: (i) Average composition of the weld is in the Ni–rich side of the phase diagram (Ni–40at.%Ti). (ii) Fusion interface microstructures are very similar to that in LW exhibiting restricted base metal growth (although little amount of epitaxy can be seen in the Ni side), growth of Ti2Ni dendrites toward the base metal at the Ti fusion interface and the sequence of layers at the Ni interface: (Ni)→ Ni3Ti→ Ni3Ti+NiTi. Unlike LW, however, Ni3Ti, instead of NiTi, reappeared after the third layer on the Ni side. (iii) General microstructure consists of the Ni3Ti+NiTi eutectic, which appears in several anomalous as well as regular morphologies. (iv) Formation of NiTi is restricted mostly to regions near the Ti fusion interface. (v) Segregation of Ni3Ti was observed in a few places. The most prominent change in the microstructure compared to LW is a shift from the Ti2Ni– NiTi phases in the bulk of the weld to a Ni3Ti+NiTi eutectic structure. This is a direct consequence of the shift in the average composition of the weld to the Ni– rich side. The occurrence of different anomalous and regular eutectic structures bear similarity with bulk undercooling experiments conducted on eutectic systems having a strongly faceting phase as one of its constituents. The asymmetric coupled zone, along with composition and temperature fluctuation due to fluid flow, can be attributed to the origin of these structures.
Electron beam welding of Ti/Ni with a Ta interlayer
Motivated by the report of superior mechanical properties of Ti/Ni welds with an interlayer of Ta, whose melting point is much higher than those Ni and Ti, we performed EBW experiments using a Ni–Ta– Ti configuration. The key observations are: (i) The process is inherently unsteady in nature, and results in partial and irregular melting of the Ta interlayer. This partial melting essentially divides the weld into Ni–rich and Ti–rich halves. (ii) Microstructure near the fusion interface in Ni and Ti show similarities with that of the pure binary Ti/Ni welds; the phases here, however, contain Ta as a ternary addition. (iii) Microstructure in the Ti–rich half consists of dendrites of the Ni(Ti,Ta) phase with a high Ti:Ta ratio, and an eutectic formed between this phase and a (Ti,Ta)2Ni phase having significant amount of Ta. Two Ni(Ti,Ta) type phases dominate the microstructure in the Ni–rich half: the phase having a higher Ti:Ta ratio forms cells and dendrites, whereas the one of a lower Ti:Ta ratio creates an interdendritic network. (iv) Regions near the unmolten Ta layer in the middle show the formation of a sawtoothlike Ta–rich faceted phase of composition (Ta,Ti)3Ni2. Since very scarce thermodynamic data exist for the Ni–Ta–Ti ternary system, we have taken cues from the binary phase diagrams to understand the microstructural evolution. Such extrapolation, although successful to some extent, fails where phases which have no binary equivalents start to appear.
In summary, in this thesis, we explore microstructural evolution in the Ti/Ni dissimilar welds under the different settings of laser and electron beam welding processes. This study reveals a variety of phenomena occurring during dissimilar welding which lead to the formation of an extensive range of microstructural features. Although a few questions do remain, most results can be rationalised by drawing from, and extending the knowledge gained from previous studies by introducing physical and thermodynamic arguments.
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Pan, Sheng-Fu, and 潘聖富. "The Study of Dissimilar Metal Welding of Multi-component High-entropy Alloys with Stainless Steel 304." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/87578823487268508054.
Full textAbstract:
碩士國立交通大學
機械工程系所
93
The development of High-Entropy alloys has aroused considerable interest recently. Many investigations have been conducted on the microstructures, mechanical properties, corrosion resistance, heat treatment, thin film development, and phase identifications. These newly developed alloys have good corrosion and wear resistance, high-temperature mechanical properties, and specially physical and chemical properties with nanostructure. This experimental research project aimed at the investigation of weldability testing and microstructure analysis of Gas Tungsten Arc Welding (GTAW or TIG) weldments of these high-entropy alloys. In this study, a new welding material was developed to make a decent dissimilar metal welding joint of this alloy with other stainless steels. Superalloys 230 and 718 were also used as the filler metal. A series experiments included micro-hardness measurements, tensile testing, SEM and EDS analysis were conducted in this investigation. The experimental results have lead to the following conclusions： 1.The weldment with high-entropy filler metal has the best mechanical strength and ductility. 2.The tensile strength of dissimilar metal joint weldment of high-entropy alloy and stainless steel 304 is greater than that of stainless steel 304. 3.High-entropy alloy can be used as welding filler metal for the joining of same type high-entropy alloy.
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Wang, Shing-Hae, and 王星海. "Study on Welding Characteristics and Microstructuresof processing Multi-steps Dissimilar Metal Welding forFE-510 Low Alloy High Strength Steel and Nickel-baseAlloy 625." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/3w6t34.
Full textAbstract:
碩士崑山科技大學
機械工程研究所
96
This study use FE-510 high strength low alloy （HSLA）steel as pressure container base metal, and use Inconel 625 nickel-base alloy as material of working liquid、cable or related device, we combine each other by the way of SMAW ; In addition, it’s necessary to do different metal dissimilar cutting-welding process repeatedly due to the limitation of working environment, lifetime, production cost and component real operating condition. This study is necessary because of cutting-welding repeated process is influenced by the input heat and influence base metal. This study use FE-510 HSLA steel and Inconel 625 alloy, we arrange 4 test groups and do 1, 3, 6, 9 cutting-welding process separately, we research the variation of base metal through X-ray, metallography micro component analysis, SEM appearance observation, hardness, tensileexperiment and EDS element analysis. This study reveal original FE-510 HSLA steel composition has significantly changed and also appear segregation and Widmanstaetten structure due to the multi cutting-welding and air cooling process, Inconel 625 alloy has no significantly changed. Yield and tensile strength is significantly decreased and elongation is increased by the process through tensile experiment following 9 times cutting-welding process. In addition, FE-510 HSLA steel hardness was higher than base metal in initial stage and then decreased by the cutting-welding times, the results is the same as metallography and tensile experiments.
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Fan, Pao-lung, and 范寶龍. "Experiments of Friction Stir Welding of Dissimilar Metals." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/656y7x.
Full textAbstract:
碩士國立中山大學
機械與機電工程學系研究所
95
In this paper, Friction Stir Welding(FSW) experiments are conducted using similar and dissimilar metals of 6061-T6 Aluminum alloy, AZ-31 Magnesium alloy, JISC-1100 pure copper as specimens. Thermalcouples of type D are used to measure temperature history at different postions of workpiece duing Fsw. Form the temperature history, the preheating temperature and the tool rotation and tool moving speed can be found for a successful welding process. The experimental results show that the temperature ranges for the tool starting to move after preheating are 250-2500C, 200-2500C and 300-3500C for silimar metals of Al alloy, Mg alloy and pure copper and that for of dissimilar of Al alloy and Mg alloy is 200-2500C. Vickers hardness test and tensile test of the welded products are also conducted. The hardness testing results show that the vickers hardness of similar Al alloy, Mg alloy and pure copper sheets beforing weldig are about, 102, 70 and 105HV, respectively. The hardness of the nugget region of similar Al alloy, Mg alloy and pure copper sheets after welding are about 60, 62 and 65 HV, respectively and that for dissimilar of Al alloy and Mg alloy sheets is 138HV. The tensile testing results shows that for similar of Al alloy, Mg alloy and pure copper sheets beforing weldig are about, 320, 300 and 280MPa, respectively. The tensile strenghts of similar Al alloy, Mg alloy and pure copper sheets after welding, are about 160, 250 and 200 MPa, respectively, and that for dissimilar Al and Mg alloys is 100 MPa. The above experimental results can provide information for Fsw of Al, Mg alloys and pure copper. Keywords：Friction Stir Welding；thermalcouple；temperature career
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Ye, Jine-wei, and 葉建偉. "Optimizating Resistance Spot Welding Parameters for Dissimilar Metals Joints." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/umzbk3.
Full textAbstract:
碩士國立虎尾科技大學
材料科學與綠色能源工程研究所
102
The main purpose of this study is use duplex stainless steel (SAF 2507) and nickel-base superalloys (Inconel 600) to find the optimizing the quality in DC power supply for resistance spot welding. the chrome zirconium copper alloy for the electrode tip material plane electrode, and shear strength as a quality spot welding pieces of property evaluation, in order to obtain the most efficient process of this good parameter values, this study Taguchi method (Taguchi Method), with the impact of the four factors that control the charging voltage、welding time、electrode force and electrode tip size to optimize the process parameters, and through variance analysis (ANOVA) to find out the degree of influence of each parameter on the manufacturing process. Experimental results show that the best combination of parameters is A1B3C1D1, the parameters are 300 V in charging voltage, 4 sec in welding time, 4 kg in electrode force and 4 mm in electrode tip size, this parameter has a higher average shear strength, and in the analysis of variance can be get the electrode head size factor greatest impact on the manufacturing process, the contribution value of 64.8%.
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Kuo, Kuo Yang, and 郭養國. "Experimental Measurements of Metals Processing (1)Electron Beam Welding Dissimilar Metals." Thesis, 1998. http://ndltd.ncl.edu.tw/handle/06889753126094200757.
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Jiang, Shiau-Jiun, and 江曉均. "Microstructural Evaluation and Welding Reliability of Friction Stir Welding Al and Cu Dissimilar Metals." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/rksqs9.
Full textAbstract:
碩士國立虎尾科技大學
材料科學與綠色能源工程研究所
102
Wrought aluminum (Al) and Cu alloys are generally used by welding with structural homogeneous or dissimilar joints for the engineering applications. However, high temperature of the traditional fusion welding will reduce the weldability and the joining strength of Al/Cu joints. Thus, the development of friction stir welding (FSW) of dissimilar metals, which has energy consumption, eco-friendly and simple welding process, has been focused by many researchers. The aim of the present study is to join the dissimilar Al and Cu alloys by the FSW technique. The AA1050, AA6061-T6 rolled Al alloys, commercial C1100 and C2600 Cu alloys are selected to conduct a friction stir welding of the Al/Cu dissimilar joints, microstructural analysis and microhardness variation of the stir welding zone, and tensile bonding tests for Al/Cu, dissimilar joints. The results indicate that dissimilar AA1050/C1100, AA6061-T6/C1100 and AA1050/C2600 alloys are successfully joined by the FSW technique. The microstructural observation along WD cross-sections showed that the above-mentioned FSW dissimilar alloys are welded with a defect-free welding zone by the significant plastic flow. The microhardness is increased after the welding. In addition, intermetallic compounds (IMCs) of Cu9Al4 and AlCu2 are found at FSW Al/Cu joint interface. Tensile testing results of these dissimilar joints show that the tensile welding strength of AA1050/C1100, AA6061-T6/C1100 and AA1050/C2600 alloys are 107.73, 212.2, and 54.17 MPa, respectively. The Weibull statistical analysis results show that the fracture of the above-mentioned FSW Al/Cu dissimilar joints belongs to an increasing failure rate (IFR) type. The FSW technique is a reliable joining process to weld the Al and Cu dissimilar alloys.
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Huang, Sin-Yi, and 黃心怡. "Optimization study on Cu-Fe dissimilar metals in DC Resistance Spot Welding." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/evcat5.
Full textAbstract:
碩士國立臺北科技大學
工業工程與管理研究所
98
This research is about the optimization study on Cu-Fe dissimilar metals in DC Resistance Spot Welding. In this study, 100 mm × 25 mm × 1t mm material of iron (JIS-G3141 SPCE) and copper (JIS-C1100) for resistance spot welding processes, use DC power supplies for resistance spot welding. Electrode materials were for the molybdenum and chromium copper alloy plane electrode. Study of three influencing control factors: welding current, welding time and the electrode force of the welding results. Finally, Used Tensile-shear test to assessed differences of Tensile-shear strength and nugget. This study had used Taguchi method of the L8 orthogonal array to plan the experiment, the Taguchi method of factor analysis and ANOVA to identify the optimum process parameters, and use back-propagation network (BPN) to assist in identifying optimum process parameters and predict the optimum process parameters results. Eventually, by the confirmation test and verify the results calculated confidence interval. The results show that using the Taguchi method, ANOVA, and the back- propagation network of the optimum process parameters are: the welding current 12 (kA), welding time 6 (cycles) and the electrode force 240 (kg). The experiment also confirmed that the optimal combination of parameters with a reproducibility.
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Yen, Chi-Ying, and 閻其暘. "Study of Friction Welding of Dissimilar Metals by High Frequency Induction Heating." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/4u3s3v.
Full textAbstract:
碩士國立中山大學
機械與機電工程學系研究所
106
In this study, Friction Welding experiment of Dissimilar metals of 10mm diameter AISI 1045 carbon steel and SUS 304 stainless steel by high frequency induction Heating was carried out .In addition a finite element analysis software DEFORM is used to analyze the welding temperature under various forming condition such as in different coil types of double-twisted solenoid、 triple-twisted concentric and U-type and coil offset position of 0、1、 2、 3、4、5 mm .A better coil position offset for a better finished product during the experiment. The mechanical properties are obtained using shear test and the hardness test were evaluated for the products after the crimping test. It is found from the shear test results that the surface treatment of the test piece before welding affects the shear strength of the welded interface, and because the welding interface is affected by high temperature and high pressure, the hardness of the welded surface will increase greatly. The failure mode is brittle failure. In terms of microstructure, it is observed that the grain will have a will fine grain zone is near the welding interface.The refine zone will become larger as the welding temperature increases. In addition, there is a layer of light gray precipitating on the joint interface, and this layer will cause severe hardening of the area.
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Huang, Jhih-Ren, and 黃志仁. "Investigation of Microstructure and Mechanical Properties of Micro-Tungsten Inert Gas Welding on Dissimilar Metals between Beryllium Copper Alloy and Ferritic Stainless Steel." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/suszza.
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碩士國立虎尾科技大學
材料科學與工程系材料科學與綠色能源工程碩士班
105
In this paper, beryllium copper alloy and ferritic stainless steel were welded by micro-gas tungsten arc welding. The working ranges of welding parameters were fixed by conducting trial runs and satisfactory results obtained were used to conduct an experimental study. Experiments were conducted applying ultrasonic vibration during the arc welding process and their effects on microstructure and mechanical properties of welds were presented. The observations of microstructure revealed that Fe-Cu compound in the weld metal was confirmed and no precipitation was recorded in weld metal or heat-affected zone. Spherical Fe-Cr sigma-phase precipitates of different diameters were observed in weld metal and heat-affected zone under ultrasonic vibratory condition. The weld joints fabricated with ultrasonic output power 55W condition were found to possess comparatively high hardness value and high ultimate tensile strength, but loss in the ductility. These results were closely associated with the precipitation behavior of sigma-phase.
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Martins, Flávio Gonçalves. "Determinação da velocidade de placas metálicas aceleradas por explosivo." Master's thesis, 2017. http://hdl.handle.net/10316/83396.
Full textAbstract:
Dissertação de Mestrado Integrado em Engenharia Mecânica apresentada à Faculdade de Ciências e TecnologiaEste projeto tem como objetivo avaliar em termos numéricos, para configurações planas, a evolução da velocidade da placa voadora em função da espessura do explosivo e da espessura da placa voadora. A aceleração da placa voadora foi estudada para uma configuração lateral e frontal à onda de detonação. O software de simulação numérica utilizado foi LS-DYNA 2D, um código de elementos finitos, Lagrangeano, que permite a análise da resposta dinâmicas em sólidos bidimensionais. O modelo para a detonação do explosivo foi o explosive Burn com uma EoS JWL. A equação de estado para a placa metálica foi a equação de Grüneisen associando ao modelo de comportamento Johnson Cook (JC). O estudo foi realizado com ANFO para uma espessura a variar entre 20 e 30 mm. A placa voadora, de cobre ou alumínio, variou entre 1 e 10mm. De uma maneira geral, nas configurações estudadas, observou-se uma diminuição da velocidade terminal com o aumento da espessura da placa voadora enquanto que, aumentando a espessura do explosivo, a velocidade terminal aumentou. Os resultados numéricos para a velocidade terminal da placa voadora foram comparados com o modelo de Gurney. Em função da energia de Gurney do explosivo, associada a um estado de expansão, verificou-se uma concordância com os resultados numéricos obtidos. No caso de uma onda de detonação frontal, os resultados numéricos obtidos evidenciam a existência de uma de choque a refletir na placa metálica durante o processo de aceleração, por oposição ao processo de aceleração da placa por uma de detonação lateral onde parece não existe onda de choque. O estudo em causa é relevante no processo de soldadura por explosão de metais dissemelhantes, uma vez que neste processo é muito importante conhecer a evolução da velocidade da placa voadora até ao momento de colisão com a placa base.
The purpose of this project is to evaluate numerically, the evolution of flying plate speed considering the thickness of the explosive and the thickness of flying plate in planar configuration. The acceleration of flying plate was studied from a lateral and frontal setting to the detonation wave. The numerical simulation software used was LS-DYNA 2D, a finite element code, Lagrangian, which allows the dynamic response analysis of two-dimensional solids. The model for the detonation of the explosive was the explosive Burn with a EoS JWL. The equation of State for metal plate was the Grüneisen equation involving the behavioral model Johnson Cook (JC). The study was conducted with ANFO, with a thickness ranging between 20 and 30 mm. The flying plate, copper or aluminum, ranged between 1 and 10 mm. In general, in the configuration studied, we observed a decrease in terminal velocity with the increasing of the thickness of flying plate, while increasing the thickness of the explosive, increased the terminal velocity. The numerical results for the terminal velocity of flying plate were compared with the Gurney model. Depending on the Gurney energy of the explosive, associated with the state of expansion, there has been an agreement with the numerical results obtained. In the case of a wave front detonation, the numerical results obtained demonstrate the existence of a shocking wave that reflects on metal plate during the accelerating process; on the other side, when it comes to the process of acceleration of a lateral detonation, it seems there is no shocking wave. The study in question is relevant in the welding process for dissimilar metal explosion, since this process is very important to know the evolution of the speed of the flying plate until the moment of collision with the base plate.