• Journal of Welding and Joining
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• v.11 no.4
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• pp.44-56
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• 1993

The arc welding processes are substantially nonlinear, in addition to being highly coupled multivariable systems, Frequently, not all the variables affecting the welding quality are known, nor may they be easily quantified. From this point of view, decoupling between the welding parameters from the welding quality is very difficult, which makes it also difficult to control the welding parameters for obtaining the desired welding quality. In this study, a neural network based on the backpropagation algorithm was implemented and adopted for the selection of gas metal arc welding parameters of the fillet joint, that is, welding current, arc voltage and welding speed. The performance of the neural network for modeling the relationship between the welding quality and welding parameters was presented and evaluated by using the actual welding data. To obtain the optimal neural network structure, various types of the neural network structures were tested with the experimental data. It was revealed that the neural network can be effectively adopted to select the appropriate gas metal arc welding parameter of fillet joints for a given weld quality.

• Transactions of Materials Processing
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• v.24 no.4
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• pp.256-263
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• 2015

Electric resistance spot welding has been used to join overlapped steel sheets in automotive bodies. Recently to reduce weight in automotive vehicles, non-ferrous metals are being used or considered in car bodies for hoods, trunk lids, doors parts, etc. Various welding processes such as laser welding, self-piercing rivet, friction stir welding are being used. In the current study, a new electric resistance heated friction stir spot welding is suggested for the spot welding of non-ferrous metals. The welding method can be characterized by three uses of heat -- electric resistance heating, friction stir heating and conduction heating of steel electrodes -- for the fusion joining at the interfacial zone between the two sheets. The welding process has variables such as welding current, diameter of the steel electrodes, revolutions per minute (rpm) of the friction stir pin, and the insert depth of the stir pin. In order to obtain the optimal welding variables, which provide the best welding strength, many experiments were conducted. From the experiments, it was found that the welding strength could be reached to the required production value by using an electrode diameter of 10mm, a current of 7.6kA, a stirring speed of 400rpm, and an insert depth of 0.8mm for the electric resistance heated friction stir spot welding of 5052 aluminum 1.5mm sheets.

• Journal of Welding and Joining
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• v.13 no.1
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• pp.145-155
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• 1995

Continuous wave C $O_{2}$ laser beam welding and formability of zinc coated steel plates were investigated. First, the optimal welding condition could be obtained in lap configuration by using the data for heat input, gap size and fracture behaviour. The gap size for fully-penetrated bead could be predicted by the gap model by Akhter et al. AIso, it was found that the joining efficiency was constant. Secondly, the butt welding of dissimilar materials (zinc coated steel plate and cold rolled steel plate) with different thicknesses was investigated. In the thickness range of 0.8-2.0 mm, the maximum welding speed of 10m/min was obtained. In the butt welding of two plates with thickness 2.0 mm and l.6mm, the maximum, welding speed of 6m/min was obtained, Finally. the forming results of butt-welded plates showed that the joining design was important to apply the laser welded blank in the automotive production.

• Journal of Welding and Joining
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• v.23 no.6
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• pp.55-60
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• 2005

In part 1. optimal process parameters such as thickness of stopper and welding time are achieved to produce high strength ISB(Inner Structured and Bonded) panels. Developed process is different from the usual resistance welding process in the number of points welded at a time. In part 2, Numerical modeling for this new process is proposed and the variation of contact area with respect to the gap of electrodes is studied through FE analyses, Besides, it is tried to figure out the welding nugget formation and proper distance between welding points. FE analytic results show that inner structures are melted more than skin plate, and current distribution between points to be welded can be controlled by distance welding points. Comparison of some FE analytic results with corresponding experimental results could confirm the validity of the proposed numerical modeling.

• International Journal of Korean Welding Society
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• v.3 no.1
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• pp.8-16
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• 2003

A major concern in Gas Metal Arc (GMA) welding process is the determination of welding process variables such as wire diameter, gas flow rate, welding speed, arc current and welding voltage and their effects on the desired weld bead dimensions and shape. To successfully accomplish this objective, 81 welded samples from mild steel AS 1204 flats adopting the bead-on-plate technique were employed in the experiment. The experimental results were used to develop a mathematical model to predict the magnitude of bead geometry as follows; weld bead width, weld bead height, weld bead penetration depth, weld penetration shape factor, weld reinforcement shape factor, weld bead total area, weld bead penetration area, weld bead reinforcement area, weld bead dilution, length of weld bead penetration boundary and length of weld bead reinforcement boundary, and to establish the relationships between weld process parameters and bead geomery. Multiple regression analysis was employed for investigating and modeling the GMA process and significance test techniques were applied for the interpretation of the experimental data.

• Journal of Welding and Joining
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• v.29 no.3
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• pp.64-69
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• 2011

Since welding process for most pipelines with large diameter has been carried out by the manual process, automation of the welding process is necessary for the sake of consistent weld quality and improvement in productivity. Therefore the development of the optimized algorithm to decide the welding condition is an effective technique to prove the feasibility of interface standards and intelligent control technology to increase productivity and reduce the cost of system integration. In this study, the pipe welding experiment has been carried out using plused GMA welding process to select optimal welding condition. And necessary information in root-pass welding has been obtained by applying in the pipeline using the selected welding conditions through the welding experiment.

• Transactions of Materials Processing
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• v.23 no.5
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• pp.282-288
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• 2014

It is difficult to control welding variables during spot welding of non-ferrous metals like aluminum because of the low electrical resistance of the material. It has been suggested that a solid state welding process such as friction stir spot welding or extru-spot welding can be used to spot weld aluminum plates. In the extru-spot welding, there is a need to increase the weld strength by improving the shape of the welding die. The current study shows that the weld strength for an extru-spot welding can be increased by using a pin placed on the inside of the upper electrode in the welding die. In the current study, the deformed shape of the insert rivet and the stress distribution in the welding zone were analyzed by simulation. Extru-rivet spot welding experiments were performed by changing the height of pin on the inside of the upper electrode. From the experimental result, it is shown that the weld strength for an extru-rivet spot welding can be increased by adjusting the height of the pin. The optimal shape of the deformed rivet after the extru-rivet spot welding can be observed from the simulation results. The deformed shape of the insert rivet can also be controlled by the height of pin.

• Proceedings of the KIPE Conference
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• 1997.07a
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• pp.40-44
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• 1997

Along with the rapid growth in microelectronics and power electronics technologies, various advanced control methods have been successfully implemented in real time and shown to be useful in controlling CO2 arc welding systems with high dynamic performance. In this paper, the slope of welding currents is controlled not to be so high in the case of short circuit welding mode. This results in less spatter. In addition, the data-base is constructed for the optimal welding conditions.

• Proceedings of the KWS Conference
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• 2006.10a
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• pp.158-160
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• 2006

Super alloys are typically used for the liquid thruster in the aerospace industry. In this work, The bead-on-plate welding of Inconel 600, Inconel 625 and Haynes 230 using Nd:YAG laser are studied, in order to examine the effects of experimental parameters on their weldability. The micro-hardness and tensile strength of the specimens are also analyzed, to obtain the optimal welding conditions.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.04a
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• pp.176-180
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• 1996

Continuous wave CO$_{2}$laser beam welding and formability of zinc coated steel shets were investigated. First, optimal welding condition could be obtained in but welding by using the data for heat input and welding velocity. The highest value of Erichsen test is 79.3% compare to that of base matel. Secondly, Formability of laser welds was investigated by using ball punch tester. Finally, the forming results of butt-welded sheets showed that the joing design was important to apply the laser welded blank in the automotive production.