Journal of Light Metal Welding
Online ISSN : 2186-618X
Print ISSN : 0368-5306
ISSN-L : 0368-5306
Volume 58 , Issue Supplement
Journal of Light Metal Welding INALCO2019 Special Issue
Showing 1-28 articles out of 28 articles from the selected issue
  • Tadashi Aiura
    Type: REVIEW
    2020 Volume 58 Issue Supplement Pages 1s-7s
    Published: 2020
    Released: April 16, 2020
    JOURNALS FREE ACCESS
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  • Hidetoshi FUJII
    Type: Extended Abstract
    2020 Volume 58 Issue Supplement Pages 8s-13s
    Published: 2020
    Released: April 16, 2020
    JOURNALS FREE ACCESS

     A new welding method called low-temperature linear friction welding has been developed for joining various kinds of materials such as aluminum alloys, steel and dissimilar materials. For heat-treatable aluminum alloys such as the 6000 series alloys, an approximate 70% joint efficiency is generally obtained even when using friction stir welding, because the precipitates are coarsened or disappear due to the high welding temperature. When using this newly developed welding method, the welding temperature can be uniquely controlled by changing the applied pressure. By decreasing the welding temperature, joints with a 100% joint efficiency were obtained even for the heat-treatable alloys such as the A6061 alloys. For many other alloys, 100 % efficiency joints are easily obtained. As an example, for a medium carbon steel, welding without any transformation is also possible because the peak temperature can be decreased to below the A1 point. It was revealed that the welding temperature is determined as the temperature at which the ultimate tensile strength of the interface material decreased below the applied pressure. When the temperature dependence of the material strength is already known, the welding temperature can be completely controlled. Therefore, the welding temperature is determined by controlling the applied pressure. A thin 2 mm thick plate can be welded using this method, and the welding is completed within several seconds.

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  • Zhuguo Li, Junhao Sun
    Type: PAPER
    2020 Volume 58 Issue Supplement Pages 14s-18s
    Published: 2020
    Released: April 16, 2020
    JOURNALS FREE ACCESS

     The wettability of Aluminum with the galvanized steel was investigated to understand the role of Zn coating during laser welding-brazing of Aluminum/steel. Then butt joining of Aluminum/steel with different Zn coating thickness was conducted with laser welding-brazing method. For the weldability experiment, different laser power with a sustaining time of 1 s was considered. ER4043 with a feeding rate of 5 m/min was applied. The transferring, wetting and spreading process of Aluminum drop on the steel surface was observed and recorded with a high speed video camera. The temperature field was measured by an infrared thermometer. The microstructure of the joint was observed and analyzed after welding. It was found that the Zn coating improved the wettability of Aluminum/steel by protecting the steel surface from oxidation and absorbing the excessive heat input. For the butt joining experiment, different thickness of the coatings including 0 μm, 20 μm and 100 μm were used. The weld appearance, microstructure and joint strength was observed and tested. The Zn coating could improve the appearance, increase the joint strength, and suppress the Fe-Al intermetallics thickness by decreasing the temperature at the interface of butt joint of Aluminum/steel. However, a relatively thicker coating deteriorated the joint appearance and strength. Maximum tensile strength of 175 MPa was achieved.

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  • Tetsuya Ando, Ryota Enomoto, Yusuke Yoshida, Kazuhiro Ito
    Type: PAPER
    2020 Volume 58 Issue Supplement Pages 19s-23s
    Published: 2020
    Released: April 16, 2020
    JOURNALS FREE ACCESS

     During solidification, die-cast aluminum alloys generally exhibit poor ductility because of casting defects and the formation of elongated silicon particles; therefore, we used screw fixing to make connections in die-cast aluminum alloys. In this study, the effects of effect of friction stir processing (FSP) treatment, which was reported to improve the ductility, on aging properties of a die-cast Al-Si-Cu-Mg alloy using Vickers hardness test was investigated. Transmission electron microscopy (TEM) was performed to observe the precipitates that formed by aging the sample. After FSP treatment, the coarse defects in the die-cast Al-Si-Cu-Mg alloy disappeared, and the elongated silicon particles were broken up into spherical morphology. The maximum hardness of the FSP-treated sample aged at 423 K was similar to that of an untreated die cast sample. By using TEM, the precipitates in the peak-aged FSP-treated sample were estimated as β′ phases, which differed from previous reports for precipitates from a die-cast Al-Si-Cu-Mg alloy. The precipitates of the over-aged FSP-treated sample were classified as β′ and θ′ phases. Thus, the FSP treatment appeared to affect the solution of additive elements, thereby changing the precipitation mechanism. These results show that localized FSP treatment can be used to produce parts that require partial ductility during plastic deformation.

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  • Michinori Okubo, Kaori Nagai, Kiyoshi Shinoda
    Type: PAPER
    2020 Volume 58 Issue Supplement Pages 24s-28s
    Published: 2020
    Released: April 16, 2020
    JOURNALS FREE ACCESS

     The weld crack sensitivity of aluminum alloys is influenced by factors such as the welding process, base metal, filler metal, welding conditions, stress, and restraint. In this work, crack sensitivity is evaluated by ten-sile-restraint crack test and self-restraint crack test. In the tensile-restraint crack test, TIG welding was performed on 0.8-mm-thick plates of A2017 (Al-Cu) and A6061 (Al-Mg-Si). In this test, tensile stress is applied to the base metal before welding. Consequently, the relationship between sensitivity to cracking and the tensile stress added to the base metal could be determined. Furthermore, the crack mode and crack propagation phenomena were revealed by scanning electron microscope and high-speed camera observations. In the self-restraint crack test, the Mn content in A6082 (Al-Mg-Si) was varied from 0 to 0.7 mass%. The crack test method was a TIG fan-shaped crack test with a plate thickness of 3.0 mm. The TIG and MIG spot weld crack tests used a plate thickness of 6.0 mm and the filler metal for MIG welding was A5025-WY (Al-Mg-Si-Sc). In the TIG fan-shaped crack test, the sensitivity to cracking decreased as the amount of Mn in the base metal increased, and a low melting point compound was found at the starting point of the cracking. In the TIG and MIG spot weld crack tests, the sensitivity to cracking of the heat-affected zone was evaluated, and increasing the amount of Mn in the base metal lowered the crack sensitivity.

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  • Isaac Chang, Dan Luo, Kawther Al-Helal, Jayesh B Patel, Yan Huang, Geo ...
    Type: PAPER
    2020 Volume 58 Issue Supplement Pages 29s-32s
    Published: 2020
    Released: April 16, 2020
    JOURNALS FREE ACCESS

     Recycling of scrap Al requires 5% of energy and saves 95% of CO2 emission as compared to the production of primary Al. Hence, there is an increasing demand to exploit the use of recycled Al alloys to reduce energy consumption and carbon footprint associated with the manufacturing processes. However, a major technical challenge to the widespread use of recycled Al is the presence of high impurity content such as Fe, which can severely deteriorate its mechanical performance. Hence, the development of a new technology is crucial to the production of good quality recycled Al alloys from the metal scrap. A melt conditioned direct chill (MC-DC) technology has been developed at BCAST which is based on the application of a high shear dispersive mixer in the molten alloy prior to solidification to produce a fine as-cast microstructure with reduced segregation in the absence of any grain refiners. This study is concerned with the microstructure/properties of recycled AA6111 Al alloy billets produced from two different metal scraps including Incinerator Bottom Ash (BA) and Old Rolled Taint Tabor (TT), using a combination of the novel MC-DC, together with a combination of hot extrusion, cold rolling and heat treatment processes.

     The production of recycled AA6111 aluminium alloy blanks with good mechanical performance comparable to primary AA6111 alloy has been demonstrated via melt conditioned DC casting of metal scraps together with downstream thermomechanical processing using extrusion and rolling operation. Sample processed from Old Rolled Taint Tabor (TT) metal scraps gives similar alloy composition and mechanical performance after T6 heat treatment. However, sample processed from Incinerator Bottom Ash (BA) metal scrap consisted of relatively high amount of Si content, leading to finer grain structure and marginally better mechanical performance in T4 condition.

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  • Feng ZHU, Yoshiaki KUBOTA, Keita YAMAGUCHI, Masashi KAWASAKI
    Type: PAPER
    2020 Volume 58 Issue Supplement Pages 33s-37s
    Published: 2020
    Released: April 16, 2020
    JOURNALS FREE ACCESS
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  • Noriyuki Matsuoka, Masaru Kowa, Takamichi Komatsu, Kimiya Sato, Junji ...
    Type: TECHNICAL REPORT
    2020 Volume 58 Issue Supplement Pages 38s-42s
    Published: 2020
    Released: April 16, 2020
    JOURNALS FREE ACCESS

     A novel arc welding process to obtain a beautiful wave-shaped weld bead was developed for welding aluminum alloys. In order to clarify the wave-shaped weld bead, it was found that it is effective to provide an arc-OFF period between two arc-ON periods for cooling molten pool. For this reason, a pulsed arc welding with high heat input was mainly performed in this process. In addition, before the pulsed arc welding a short-circuit transfer type of arc welding by a forwardly and reversely controlled wire feeding was used to reduce spatter. When welding rigid aluminum alloys, high frequency pulse without droplet detachment was also superimposed during base current period. As a result, it was found that elimination of unevenness in weld bead, avoiding convex bead, and suppression of smut could be achieved.

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  • Zhongjie Liu, Keiji Kadota, Kento Takada, Tetsuo Era, Tomoyuki Ueyama
    Type: TECHNICAL REPORT
    2020 Volume 58 Issue Supplement Pages 43s-47s
    Published: 2020
    Released: April 16, 2020
    JOURNALS FREE ACCESS

     CO2 emission control of vehicle became more and more strict. For example, the emission by automobile should be less than 95 g/km in EU by the end of 2021. Weight saving, such as using aluminum alloys instead of steel, is an effective method to comply the regulation. For joining those aluminum alloy parts, high efficiency and high quality welding process is required. Tungsten Inert Gas (TIG) welding process is a high quality welding process, but it has some disadvantages of lower deposition rate and shallow penetration. Especially, the penetration becomes shallow in aluminum alloys welding using Alternative Current (AC) TIG welding, because the arc shows poor concentration in the polarity of Electrode Positive (EP) than in the polarity of Electrode Negative (EN).

     Then new digital inverter controlled AC TIG welding power source has been developed. The power source has high speed current response to realize stable output at a range of 5 A to 500 A and AC frequency up to 500 Hz. As increasing AC frequency in the AC TIG welding process, the arc has become concentrated extremely. The concentrated arc has reduced the time from arc start to weld pool formation in fillet joint, and enabled high-quality thin plate edge welding of 0.2 mm thick JIS A 1050. Even in 100% argon shielding gas, using AC-DC switching TIG welding with AC frequency of 500 Hz has penetrated to levels similar to the penetration depth by normal AC TIG welding with AC frequency of 300 Hz in 30%He-70%Ar gas. It has shown that AC-DC switching TIG has advantage to reduce production cost because expensive helium gas is not necessary to penetrate deeply.

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  • Muneyoshi Iyota
    Type: PAPER
    2020 Volume 58 Issue Supplement Pages 48s-53s
    Published: 2020
    Released: April 16, 2020
    JOURNALS FREE ACCESS

     In this study, effects of plate thickness on joint strength of resistance spot-welded aluminum alloy were investigated. A5052 and A6061 were used as the test materials. First, in order to investigate the change of joint strength with changing the plate thickness, tensile shear (TS) test and cross tension (CT) test were conducted on resistance spot welded joints using 2 mm thickness plates, respectively. Experimental results on fracture mode of the joints indicated that CT joint had cracks and plastic deformation from the low load range compared with the TS joint. Next, in order to discuss about this experimental results and effects of plate thickness, numerical simulation was performed. Numerical simulation was modeled by simulating the TS test and CT test in the experiment, and the mechanical property of spot welds was simulated based on the hardness distribution and stress-strain curve of base material obtained from the experimental result. Numerical simulation results indicated that CT joint was affected by changes in plate thickness compared to TS joint. Moreover, the stress intensity factor under low load conditions and the equivalent plastic strain under high load conditions varied significantly in the CT joint compared to the TS joint. These results suggested that the CT test was a test that greatly depended on the bending deformation resistance of the plate.

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  • Yasumasa Okada, Nobuyuki Funahira, Keisuke Tsuta, Akiyoshi Miyawaki, Y ...
    Type: PAPER
    2020 Volume 58 Issue Supplement Pages 54s-59s
    Published: 2020
    Released: April 16, 2020
    JOURNALS FREE ACCESS

     Honda developed a technology for joining aluminum and steel in automobile parts using friction stir welding (FSW). It is applied to the mass production of front subframe, which is an important structural component of vehicles, and about 2.3 million units have been manufactured over a six-year period. In this technology, wear of the tool is more severe than in the conventional aluminum-to-aluminum FSW. In order to address this problem and improve the competitiveness of this FSW method, we developed a new tool with enhanced wear resistance as well as adequate productivity, based on high-speed steel. The key is controlling hardness distribution in the tool by applying a special heat treatment technique. In a welding test using mass production welding equipment, it was confirmed that the wear resistance of the developed tool improved by nine times compared to the conventional tool.

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  • Markus Weigl, Michael Gratzel, Jean Pierre Bergmann
    Type: PAPER
    2020 Volume 58 Issue Supplement Pages 60s-64s
    Published: 2020
    Released: April 16, 2020
    JOURNALS FREE ACCESS
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  • Egoitz Aldanondo, Ekaitz Arruti, Amaia Iturrioz, Ivan Huarte, Fidel Zu ...
    Type: PAPER
    2020 Volume 58 Issue Supplement Pages 65s-71s
    Published: 2020
    Released: April 16, 2020
    JOURNALS FREE ACCESS

     Manufacturing aeronautic structures joining extruded profiles or stringers to sheets or skins of aluminium is a typical procedure in aeronautic structures. Although riveting is the conventional manufacturing technology to produce such joints, Friction Stir Welding (FSW) and Laser Beam Welding (LBW) technologies have also demonstrated their potential for this kind of applications, showing benefits such as time saving, light-weighting and overall cost reduction. In addition to that, new aluminium-lithium based alloy developments represent great opportunities for advanced aeronautic structure manufacturing with potential benefits such as lightweight construction or improved corrosion resistance.

     This work presents the main approaches by FSW and LBW to produce stiffened panel structures such as fuselage by stringer-skin joints and using innovative aluminium-lithium alloys. The work was performed using AA2198, AA2060 and AA2099 alloys. The weld quality and properties have been examined by metallographic analysis and mechanical testing. The effects produced by innovative Cr-free surface treatments and coatings on joint properties was also investigated.

     The analysis of the results have shown the relationships between processing conditions, micro-macrostructural properties and the mechanical strength of the welded joints. The effects produced in the different alloys investigated have been observed and particular weld formation mechanics have been studied for each material and welding technology.

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  • Rakesh Ranjan, Scott Walbridge, Luqman Shah, Adrian Gerlich
    Type: PAPER
    2020 Volume 58 Issue Supplement Pages 72s-76s
    Published: 2020
    Released: April 16, 2020
    JOURNALS FREE ACCESS

     Recent studies have suggested that friction stir welding (FSW) represents a transformative technology, which could have a significant influence on the durability and economics of extruded aluminum decks for vehicular bridge construction and retrofitting applications. Design codes in Canada are only just starting to acknowledge FSW as a viable welding process for structural applications. Existing international codes (e.g. ISO, AWS) include quality control (QC) provisions, which appear to be based on “best practice”, rather than a correlation with expected fatigue performance. With this in mind, a recent project was undertaken, which included the following tasks: 1) FSW specimen preparation and metallurgical analysis; 2) fatigue testing of FSW specimens; and 3) fracture mechanics analysis of the test results. A novel aspect of the project was the fatigue testing and analysis of welds with varying levels of quality (i.e. various defect types with varying degrees of severity intentionally introduced). In this paper, a fracture mechanics model developed previously to analyze the test results will be used along with Monte Carlo simulation (MCS) to establish probabilistic S-N (stress-life) curves for FSW joints with various defect types and degrees of severity. It is believed that curves like these can provide a basis for the establishment of improved guidelines and code provisions for the QC and fatigue design of FSW joints.

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  • Michael Grätzel, Markus Weigl, Tobias Köhler, Christian Kästner, Jean ...
    Type: PAPER
    2020 Volume 58 Issue Supplement Pages 77s-83s
    Published: 2020
    Released: April 16, 2020
    JOURNALS FREE ACCESS
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  • Hirokazu Karasawa
    Type: TECHNICAL REPORT
    2020 Volume 58 Issue Supplement Pages 84s-90s
    Published: 2020
    Released: April 16, 2020
    JOURNALS FREE ACCESS

     Friction stir welding (FSW) is applied to various types of aluminum alloy structures because this weld method has many features. It's expected to be applied to magnesium alloy structures. However, practical ultrasonic inspection method to detect micro sized flaw in FSW was not developed. In the beginning of the evaluation, we prepare FSW test samples with 0 mm, 0,1 mm and 0,2 mm high root flaw, which includes incomplete penetration and lack of penetration, made by aluminum alloy and magnesium alloy. We applied a usual phased-array ultrasonic inspection method and a new type of the phased-array TFM/FMC (Total Focusing Method and Full Matrix Capture) method as the practical ultrasonic nondestructive inspection methods to detect root flaw in FSW. In the first step, we confirmed that the above two inspection methods basically enable to detect 0 mm, 0.1 mm and 0.2 mm high root flaws in the above FSW samples by using manual scanning of linear-array probes, whose frequencies are 10 MHz (32 channels) and 15 MHz (64 channels). Secondly we applied the phased-array TFM/FMC method to evaluate scanning profile of the ultrasonic echo intensity of 0 mm, 0.1 mm and 0.2 mm high root flaws by using manual scanning of the same probes with contact method. As a result of the above evaluation, we confirmed the possibility to identify 0.1 mm and 0.2 mm height root flaw. We also developed a draft JIS document for Ultrasonic flaw detection inspection method for root flaw in FSW of aluminum alloy and magnesium alloy. It was published as JIS Z 3083 in the end of 2018.

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  • Mitsuhiro Watanabe, Shinji Kumai
    Type: PAPER
    2020 Volume 58 Issue Supplement Pages 91s-96s
    Published: 2020
    Released: April 16, 2020
    JOURNALS FREE ACCESS

     Dissimilar metal lap welding of A5052 aluminum alloy and TP340 pure titanium plates was performed by using magnetic pulse welding, and interfacial microstructure and joint strength were investigated. The A5052 aluminum alloy plate and the TP340 pure titanium plate were used for a flyer plate and a parent plate, respectively, and charging energy stored in a capacitor and plate gap between the aluminum plate and the titanium plate were changed to fabricate the joint. The welding was achieved at the charging energy above 2.5 kJ and at the plate gap above 1.0 mm. The range of the weldable charging energy increased with decreasing the plate gap. The width of the welded area increased with increasing the charging energy or increasing the plate gap. The welding interface exhibited characteristic wavy morphology. Intermediate layer was produce along the wavy interface and it was composed of fine Al-Ti supersaturated solid solution grains with approximately 100 nm diameter. In all joints, fracture by the tensile-shear test occurred at the aluminum base metal. The formation of the refined supersaturated solid solution grain is considered to result in interfacial strength enhancement of the aluminum/titanium joint.

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  • Tomokatsu Aizawa
    Type: PAPER
    2020 Volume 58 Issue Supplement Pages 97s-101s
    Published: 2020
    Released: April 16, 2020
    JOURNALS FREE ACCESS

     Magnetic pulse welding of sheets is performed by rapidly discharging a large current from a capacitor bank to a flat coil. By increasing the number of coil turns, the current can be reduced. However, if the 8-turn coil of higher inductance is used, the current rise time will be longer. It may be difficult to efficiently weld sheets. In this paper, after charging the same two capacitors (12 μF) in parallel, they are discharged in series to reduce the bank capacity. The current rise time is improved, and efficient welding results will be obtained. The overlapped Al/Cu sheets with a gap are fixed on the coil. When the series discharge current flows through the coil, a high density magnetic flux rapidly generates around the coil and electromagnetic forces act on the Al sheet near the coil. This sheet collides with the Cu sheet at high speed and both sheets are welded. The bank energy and the parallel charging voltage required for welding are 0.70 kJ and 7.6 kV respectively, and the reduced peak discharge current is 21 kA. The interface of the welded sheets is observed.

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  • Hongmei Li, Naoki Takata, Makoto Kobashi, Ai Serizawa
    Type: PAPER
    2020 Volume 58 Issue Supplement Pages 102s-106s
    Published: 2020
    Released: April 16, 2020
    JOURNALS FREE ACCESS

     In this study, in order to evaluate the adhesion properties of the hydroxide film formed on 6061 alloy (Al-1Mg-0.6Si (wt.%)) sheets prepared by steam coating, we examined the microstructure and cracking behavior of hydroxide film on Al alloy sheets prepared by steam coating at 220℃ for 24 h. EBSD analyses revealed the steam-coated sample exhibits microstructure of α-Al matrix consisted of equiaxed grains with a mean grain size of approximately 20 μm. The studied sample exhibits high hardness of 79 HV due to the strengthening by the precipitates of nanoscale particles (Mg2Si). The observation for the surface morphologies revealed the hydroxide film consisted of a number of particles with a mean size of approximately 300 nm and cross-sectional microstructural observations identified a continuous hydroxide film with a thickness of approximately 1.2 μm. The XRD measurement demonstrated the formed hydroxide film consisted of the γ-AlO(OH) phase. Minute microstructure analyses revealed that the hydroxide film exhibits a dual layer structure consisting of γ-AlO(OH) crystalline layer on the surface and a continuous Al-rich layer on the Al alloy. The cracking and delamination behavior of the hydroxide film were examined by bending test. It was found that the local delamination of γ-AlO(OH) phase would occur under compressive stress rather than tensile stress, whereas the delamination of the hydroxide film from the Al alloy substrate was not observed. These results indicate that the hydroxide film prepared by steam coating has a remarkable adhesion strength on the Al alloy substrate.

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  • Jinfeng Shu, Tomiko Yamaguchi
    Type: PAPER
    2020 Volume 58 Issue Supplement Pages 107s-112s
    Published: 2020
    Released: April 16, 2020
    JOURNALS FREE ACCESS

     The Al/Mg clad materials were produced by vacuum roll bonding. After bonding, the clad materials were heat treated at different temperatures. The growth of intermetallic compounds on Al/Mg bond interface was investigated. The results show that the growth of intermetallic compounds was very slow at 200℃ and only Al3Mg2 layer with 2 μm thickness was observed after 3h. Al3Mg2 and Al12Mg17 intermetallic layers were formed at and above 300℃, and the growth activation energy of Al3Mg2 (86.18 kJ/mol) is smaller than that of Al12Mg17 (115.33 kJ/mol), so the growth of Al3Mg2 is faster and thicker. The thickness of intermetallic layer has a great influence on the tensile strength of Al/Mg interface. When the thickness of the intermetallic layer exceeded 20 μm, the tensile strength reduced to less than 6 Mpa. After 200℃ heat treatment, ductile fracture and brittle fracture occurred simultaneously at Al/Mg interface during tensile test. After heat treatment at and above 300℃, the fracture of Al/Mg interface occurred in the intermetallic layer and mainly in the Al3Mg2 layer, and the mode of fracture were cleavage fracture.

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  • Tomo Ogura, Kazuyuki Ike, Kazuyoshi Saida
    Type: PAPER
    2020 Volume 58 Issue Supplement Pages 113s-117s
    Published: 2020
    Released: April 16, 2020
    JOURNALS FREE ACCESS

     The effects of Ti interlayer thickness on the dissimilar metals laser brazing between A5052 aluminum alloy and AZ31 magnesium alloy were investigated. The traveling velocity (Vf) to wire feeding speed (Vw) laser brazing ratio that produces good bead appearance was determined to fall within the 3-5 range. Regardless of the thickness of the interlayer, it was found that joining was possible at a Ti/A5052 interface temperature of 800℃ or higher, and that burn-through occurred when the Ti/A5052 interface temperature exceeded approximately 1060℃. The reaction layer thickness at the Ti/A5052 interface increased as the interlayer thickness decreased and as the laser power increased. Joining becomes possible when the reaction layer thickness is 1 μm or higher. Furthermore, fracture occurred in the base material of all joints produced with a laser power of 900 W, regardless of the interlayer thickness, and the material's measured strength was 80% or more of the A5052 base material strength of 235 MPa. It was found that fracturing at the Ti/A5052 interface of the joint occurred at the laser power of 800 W or lower, and brazed filler metal fracture occurred at the laser power of 1000 W or higher. It is considered that the filler metal fracture of the joint results from the propagation of individual cracks in the Mg17Al12 within the filler metal, which are caused by tensile deformation. The amount of Mg17Al12 in the filler metal of the joint increases as the laser power increases, and is 20% or higher of the total filler area when the filler metal of the joint breaks.

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  • Yuichi Kubo, Shiyo Kamibayashi
    Type: TECHNICAL REPORT
    2020 Volume 58 Issue Supplement Pages 118s-121s
    Published: 2020
    Released: April 16, 2020
    JOURNALS FREE ACCESS

     In transportation, there is the mainstream of flexible multi-material design that put emphasis on weight reducing. Multi-material is too complicated and cannot be done by existing method. Now it is done by bolt and glue which require many steps in process.

     Our company succeed in establishing short and mass production mechanical method which makes use of plastic flow. As a result, we contribute to weight reducing by applying hard metal to the parts which needs durability of wear and use light material such as Aluminum to the other parts.

     Our company have experiences of introducing this technology to the field of optics, machine tools, inspection machine and industrial equipment. Now we are trying to enter the transportation field such as vehicles and reduce weight of instruments. There is a big meaning of promoting multi-material technology to the field of transportation because we would like to contribute to our earth by reducing carbon dioxide.

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  • Michinori Okubo
    Type: TECHNICAL REPORT
    2020 Volume 58 Issue Supplement Pages 122s-126s
    Published: 2020
    Released: April 16, 2020
    JOURNALS FREE ACCESS

     The characteristics of aluminum alloy sheet welds are affected by many working conditions. I investigated the effect of working conditions on the characteristics of welds. The base metals were A2017-T3 (Al-Cu) and A6061-T6 (Al-Mg-Si) alloys, and the sheets were 0.8 mm thick. For friction stir welding, tended to produce stronger triple-lap joints than butt joints and double-lap joints. Furthermore, the welds between A2017 and A2017 had better tensile and impact characteristics than those between A6061 and A6061. The rupture position of the test pieces was at the thermo-mechanically affected zone. Joints with A6061 on top and A2017 on the bottom produced the best results. For inverted resistance spot welding, the A2017 joints tended to have better characteristics than the A6061 joints, and the characteristics of all joints were improved by increasing the welding current. The tensile properties in the cross-tension test were better for high welding currents and low electrode pressure. Furthermore, the factors in the electrode wear caused by consecutive spot welding were investigated.

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  • Michinori Okubo
    Type: PAPER
    2020 Volume 58 Issue Supplement Pages 127s-131s
    Published: 2020
    Released: April 16, 2020
    JOURNALS FREE ACCESS

     The development of filler materials is required to improve the electron beam welding properties of aluminum alloys. Filler material sheets produced by mechanical alloying were used to perform insert electron beam welding. The base materials were 15-mm-thick A5052-H112 (Al-Mg) and 12-mm-thick A7075-T651 (Al-Mg-Zn-Cu) plates. The filler material (Al-Mg-Ti-B) sheets were 0.5 and 1.0 mm thick. The filler material improved the joint efficiency of A5052 alloy joints, although the impact value was not improved. The filler material did not im-prove the properties of A7075 alloy joints. Filler rods containing scandium (Al-Mg-Sc, 3.3 mm in diameter) were used in the insert electron beam welding of 15-mm-thick A2024-T351 (Al-Mg-Cu) and A7075-T651 (Al-Mg-Zn-Cu) plates. Welding methods consisted of matching the A2024 and A7075 plates and directly weld-ing the center position by insert welding using a single rod or six rods. Finite element analysis showed that the single scandium-containing filler rod offered slightly better tensile strength than direct welding and that adding scandium improves welding properties.

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  • Toshio Haga
    Type: TECHNICAL REPORT
    2020 Volume 58 Issue Supplement Pages 132s-137s
    Published: 2020
    Released: April 16, 2020
    JOURNALS FREE ACCESS

     Two types of twin-roll caster, namely vertical and unequal-diameter types, both equipped with a scraper, were employed to cast clad strips. The clad strips made of hard aluminum alloy, wide-solidification temperature-aluminum alloy and magnesium alloy were fabricated. The layers of the clad strip were strongly bonded at the interface. The interface between the strips was clear. The elements in the overlay strip did not diffuse into the base strip. These were effect of the scraper. The clad strops with these excellent properties could be cast at the speed higher than that of the conventional twin roll caster for the aluminum alloy.

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  • Amar Djedid, Michel Guillot, Victor Desjardins, Charles-Darwin Annan, ...
    Type: PAPER
    2020 Volume 58 Issue Supplement Pages 138s-144s
    Published: 2020
    Released: April 16, 2020
    JOURNALS FREE ACCESS

     Aluminium is increasingly used to replace aging concrete, steel or wood bridge decks. Typically, aluminium decks are made from extrusions welded together using gas metal arc welding (GMAW) or friction-stir welding (FSW) techniques. This paper describes firstly the steps followed in the design of an extruded aluminium bridge deck to be supported on steel girders in highway application. The design is based on the requirements of the Canadian Highway Bridge Design Code (CHBDC). It is observed that the fatigue strength of the aluminium alloy controls the design. Accordingly, specially designed AA6005A-T61 extrusion profiles are proposed. They are optimised by exploiting the fatigue strengths in both the plain and welded areas. In the second part of the paper, a manufacturing and assembly strategy is presented. This strategy proposes a specific sequence of installation that may provide satisfactory fit and limit the effect of any geometric inaccuracies in the individual extrusions. In addition, by using the GMAW technique with multiple passes, it may be possible to reduce the effect of heat deformations, the amount of distortions and residual stresses, especially near the heat affected zones around the welds.

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  • Ippei Shinozaki, Yohei Sakakibara, Gen Nakayama
    Type: PAPER
    2020 Volume 58 Issue Supplement Pages 145s-149s
    Published: 2020
    Released: April 16, 2020
    JOURNALS FREE ACCESS

     Al-Si-Cu alloys are often used in combination with bolts made of high-strength, Ni-alloy for joining casing components together. When seawater or rainwater intrudes a joint area between an Al-alloy casing and a Ni-alloy bolt, for example, the problem of galvanic corrosion may occur in and around the joint area. Then, this study focused on the galvanic corrosion of Al/Ni galvanic pair under dry/wet cycles. To simulate the wetting/drying process of the brine, the metal pair was put on a heater, which was kept at either 150℃ for 15 min or 80℃ for 45 min. To estimate the corrosion rate in the test environment, the Al-Ni (C355.0/Alloy 718) pair was connected to a zero-resistance ammeter to measure the corrosion current between the metals. The corrosion rate of the galvanic couple of Al and Ni alloys depends on the reduction reaction of H2O in the surface water film. We have obtained the following findings as regards the corrosion acceleration test on the Al-Ni (C355.0/Alloy 718) galvanic couple and the monitoring method in the test. The amount of corrosion depends on the wetness duration, and corrosion is accelerated by maintaining the wet environment.

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  • Luigi Mario Viespoli, Ole Terje Midling, Antonio Alvaro, Bård Nyhus, F ...
    Type: PAPER
    2020 Volume 58 Issue Supplement Pages 150s-154s
    Published: 2020
    Released: April 16, 2020
    JOURNALS FREE ACCESS

     Due to its low specific mass, mechanical resistance comparable to that of mild structural steels, the low maintenance cost and good corrosion resistance, aluminum alloys are well suited for the production of offshore structures. For the specific case of the installation of structures in arctic areas, it is necessary to verify the influence of a low ambient temperature on the mechanical performance of the alloys of interest. In particular, the present work reports the results of several investigations on two alloys widely used in the sector, the EN AW 5083-H321 and EN AW 6082-T6 at room and low temperature. The tests performed, including material investigation, tensile, fatigue and fracture mechanics testing, showed no deterioration of the material performances at low temperature, indicating how such alloys are adequate structures operating in arctic environment.

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