• Journal of Welding and Joining
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• 제17권2호
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• pp.44-52
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• 1999

This study deals with spot weld ability of dissimilar aluminum alloy sheets in order to take advantage of its lightweight and strength. The paper also shows the relationship between weld elements(i.e. current, welding time and tip force) and weld quality on the resistance spot weld part of the same and dissimilar Al alloy. The conclusions are: (1) Because of excessive tip force, deep indentation remained at the Al 5182 side which is lower stiffness at the dissimilar Al alloy. (2) Weld quality (i.e. tensile shear strength) of dissimilar Al alloy is superior to that of the same Al 6061 alloy. (3) As long cycles, fatigue life of spot weld specimen on dissimilar Al alloy sheets was better than that of the same Al alloy.

• Journal of Welding and Joining
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• 제32권1호
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• pp.28-33
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• 2014

In this paper, I-butt welding with 6mm thickness using Plasma-GMA welding was carried out. And weld characteristics of the Al-5083 aluminium alloy for Plasma-GMA hybrid welding was evaluated. The orthogonal experimental design was used to investigate the influence of plasma-MIG welding parameters such as plasma current, wire feeding rate, MIG-welding voltage and welding speed on the weld bead geometry and tensile strength using the ANOVA(Analysis of Variation). Then we conducted evaluation of contribution for process parameters. ANOVA results show that bead dimensions are affected by wire feeding speed, welding voltage and welding speed and tensile strength is mainly affected by welding speed and plasma arc current. Tensile strength was decreased by rise in plasma welding current because GMA welding current was decreased by plasma arc.

• Journal of Welding and Joining
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• 제15권3호
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• pp.65-78
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• 1997

The effect of $O_2$and Al contents and the variation of welding parameters such as arc currents, welding speed on the weld penetration was investigated. Examination of weld penetration using GTAW was accomplished in the ferritic STS410L and austenitic STS304. Good penetration could be controlled by the variation of $O_2$ and Al contents in STS304. However, influences of $O_2$ and Al contents on the ferritic STS410L are far less than those on the austenitic STS304. Welding parameters should be considered first before controlling $O_2$ and Al contents for a good penetration in ferritic STS410L. In the simulation study under the stationary heat sources, the results of simulation and experiment have a similar tendency.

• Journal of Welding and Joining
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• 제20권4호
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• pp.534-537
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• 2002

In the various industry such as shipbuilding and automobile, etc., Al-alloys are used to reduce weight and improve economical efficiency, and they are mainly utilized in the process of Friction Stir Welding (FSW). A number of studies have been carried out on the metallurgical characteristics of friction stir welding In Al-alloys. However, research on the thermal behavior of FSW by using numerical analysis is not sufficient in the domestic and abroad. In this paper, therefore, numerical simulation was used to find out thermal behaviour of FSW by finite element method. We considered heat source that occurred by friction between tool shoulder including pin and base metal. To confirm the result of simulation, macrostructure is examined and compared after welding. The result of numerical simulation shows that Al-alloy is welded under a melting point of Al around pin by FSW.

• Journal of Welding and Joining
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• 제12권3호
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• pp.101-108
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• 1994

The horizontal continuous casting process with the heating mold was adopted for fabricating defect-free 4043 Al alloy rods of 3.2m dia. with mirror surfaces. These rods were drawn into 2.4mm dia. rods for GTAW welding. The GTAW welding tests were carried out by use of these welding rods with 6061 Al alloy as a base metal. After welding, the X-ray tests, tensile strength tests, bending tests, and microstructural analysis of welded zone and HAZ were carried out. The results represented that the welding rods with good surfaces and welding properties could be made by the horizontal continuous casting, and followed by the drawing process.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2005년도 춘계학술발표대회 개요집
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• pp.226-228
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• 2005

Of typical welding techniques, to employ the heat for joining process is the most commonly used welding process. But there arise difficulties when this process is applied to light weight alloys such as Aluminium alloy. In this respect, Friction Stir Welding(FSW), a solid-state joining process, is the most effective welding technique with significant potential for various industrial applications. In this study, the characteristics of lapping FSW Al 5052 alloy are shown under a variety of welding parameters such as the rotation speed of FSW tool and welding velocity. Conclusively, the welding properties of lapping FSW Al 5052 were found to be dominated by the deformation of non-joining area near the welding nugget rather than other factors such as the thermal input.

• Journal of Welding and Joining
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• 제29권4호
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• pp.35-40
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• 2011

• Journal of Welding and Joining
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• 제29권1호
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• pp.74-79
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• 2011

Three different welding wires were used to study the effects of Al content on weld metal toughness and porosity formation in self-shielded arc welding. Weld metal microstructure showed that while wire with 1.3% Al content contains coarse $\delta$-ferrite, wires with less than 0.5% Al content showed no such phase. In addition to the microstructural differences, cleanliness in weld metal was also different among wires. It showed that weld metal toughness was influenced by the $\delta$-ferrite formation, cleanliness and Ni addition. Even though wires with less than 0.5% Al content showed higher weld metal toughness, they showed relatively poor workability, forming porosities in weld bead in lower arc voltages.

• Corrosion Science and Technology
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• 제11권1호
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• pp.29-36
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• 2012

The resistance spot welding of high strength steel degrades the weldability because of its high strength with rich chemical composition and coating layer to protect from corrosion. During the each resistance welding process the electrodes tip reacts with coating layer, then subsequently deteriorates and shorten electrode life. In this study, the Al-coated HPF (Hot Press Forming) steels and Zn-coated TRIP steels were used to investigate the electrode life for resistance spot welding. Experimental results show that the reactivity of Al-coating on HPF steels to electrode tip surface behaviors different from the conventional Zn-coated high strength steels. The electrode tip diameter and nugget size in electrode life test of Al-coated HPF steels are observed to be constant with respect to weld numbers. For Al-coated HPF steels, the hard aluminum oxide layer being formed during high temperature heat treatment process reduces reactivity with copper electrode during the resistance welding process. Eventually, the electrode life in resistance spot welding of Al-coated HPF steels has the advantage over the galvanized steel sheets.

• Journal of Welding and Joining
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• 제14권4호
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• pp.53-61
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• 1996

It was attempted to improve the wear resistance of Al alloy under the load condition by making a formation of the thicker surface hardening alloy layers. The thicker surface hardening alloy layers were formed on 6061 Al alloys overlayed by MIG and TIG welding process with Cu powders feeding. The characteristics of hardening and wear resistance have been investigated in relation to the microstructures of alloyed layers, with a selection of optimum alloying conditions for formation of overlaying layer. The results obtained were summarized as follows With increasing feeding rate of Cu powders by MIG welding, the hardness and specific wear of the overlay weld alloys were increased. It is considered that these high hardness and specific wear of overlay weld alloys were due to the formation of Θ($Al_2Cu$) phases. With increasing feeding rate of Cu powders by TIG welding, the hardness and specific wear of the overlay weld alloys were increased in feeding rates 12 and 18g/min. However, the hardness and specific wear were decreased in the powder feeding rate 38g/min. It is considered that considered that decrease of hardness and specific wear in the powder feeding rate 38g/min due to formation of ${\gamma}$($Al_4Cu_9$) phases.