• 한국공작기계학회논문집
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• 제11권3호
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• pp.8-13
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• 2002

In order to obtain the basic informations for the development of high strength and high weldability aluminum alloy sheets, the experimental study was carried out to evaluate resistance spot welding characteristics and welding parameters (welding current, welding time, electrode force) far the aluminum alloy sheets. The mechanical properties of spot weld of aluminum alloy were evaluated by tensile shear test and by peel test at room temperature and also the welding possible zone was established through variation of current electrode force and welding time.

• 한국환경보건학회지
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• 제25권3호
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• pp.108-112
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• 1999

A study was conducted for the effects of input energy on fume formation ratios based on electrode(FFR$_{electrode}(g/kg_{electrode})),\;deposited\;metal(FFR_{weld}(g/kg_{weld}))\;and\;slag(FFR_{slag}(g/kg_{slag}))\;at\;CO_2$ flux cored arc welding on stainless steel. Experiments were run in well designed welding fume box. Six types of flux cored wires were used and three levels of current and voltages were given. The measured values of $FFR_{electrode},\;FFR_{weld},\;FFR_{slag}\;are\;7.90{\pm}1.47\;g/kg_{electrode},\;9.18{\pm}1.65\;g/kg_{\electrode},\;71.8{\pm}24.2\;g/kg_{slag}$ respectively. Fume formation ratios are not increased dramatically by input energy because of simultaneous increasing of melted electrodes, deposited metal and slag. The results indicate that the test of fume formation ratios in the research on production of low fume welding wire can be run at the fixed condition of input energy rather than various condition.

• Journal of Welding and Joining
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• 제7권2호
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• pp.60-69
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• 1989

The present study was aimed at investigating the effect of welding parameters such as welding current, electrode force(or squeeze force) and parts cleaning on the sound weld, and establishing the most reliable weld conditions for HWP(Heavy Water Reactor) fuel end capping with the resistance upset butt welding. Major results obtained are as follows. 1. The amount of sound weld was increased with increasing weld current(5.0-11KA) because the activated diffusion with increasing heat generation played an important role in eliminating the porosity and weld line in the weld interface. 2. It was found that weld current was not significantly influenced by the electrode force although the increase of it caused a slight increase of weld current and upset deformation. 3. Acetone rinsing before drying for the Zircaloy-4 end cap cleaning produced the reliable sound weld because it would remove the remaining solvent and surface films, and provided the uniform contact between the end cap and the tube. 4. The optimum welding conditions for fuel end capping by a resistance upset hytt welding are obtained as follows. weld current: 10-11KA, electrode force: 62-90KPa parts cleaning: vapor degreasing.rarw.water, acetone rinsing.rarw.drying.

• Journal of Advanced Marine Engineering and Technology
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• 제18권3호
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• pp.68-77
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• 1994

TIG welding process is applied for the active metal such as aluminum and titanium, also sometimes for overlay welding of superalloy. However the welding speed to be applied is very low because of the unstable bead formed in the region of high current and high welding speed. The present study was carried out to examine the basic phenomena of high speed TIG melt run welding by the 2% Th - W electrode(dia.3.2mm) of various tip shapes.

• Journal of Welding and Joining
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• 제12권4호
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• pp.127-140
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• 1994

Resistance spot welding has been widely used in the sheet metal joining processes because of its high productivity and convenience. In the resistance spot welding processes the size of molten nugget is a criterion to assess weld quality. Many research have founded on measuring weld nugget size at the same time monitoring welding process parameters such as dynamic resistance and electrode movement. With increasing demand of energy saving, many efforts were made to employ aluminum alloys that are lighter than steel and have relatively equivalent strength to steel in the automobile industry. In this paper, spot weldability of aluminum alloys for various welding conditions were examined by series of experiments. One of the 6000 series (Mg-Si) aluminum alloy, 6383-T4 was chosen, which is currently considered as a substitute for the galvanized steel. Dynamic resistance, electrode movement and corresponding nugget size were observed and compared to the case of steel. Finally, resistance spot welding of dissimilar material (galvanized steel-aluminum alloy) was attempted.

• Journal of Welding and Joining
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• 제28권4호
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• pp.73-80
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• 2010

In this work, the effect of welding variables on weldability of gas tungsten arc(GTA) welding was investigated with experimental analysis for a commercial pure(CP) titanium (Grade.1). The GTA welding tests on sheet samples with 0.5mm in thick were carried out at different process variables such as arc length, welding speed and electrode shape. In order to search an optimum arc length with full penetration, bead- on-plate welding before butt-welding were performed with different arc length conditions. From the bead- on-plate welding results, the optimum condition considering arc stability and electrode loss was obtained in the arc length of 0.8mm. Butt-welding tests based on the arc length of 0.8mm were carried out to achieve the optimum conditions of welding speed and electrode shape. Optimum conditions of welding speed and electrode shape were suggested as 10 mm/s and truncated electrode shape, respectively. It was successfully validated by the microstructural observation, tensile tests, micro-hardness tests and formability tests.

• Journal of Welding and Joining
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• 제26권2호
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• pp.75-84
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• 2008

With the development of surface roughness textured steel for automotive body-in-white assemble, one of key issues is to understand the role of the surface roughness in textured steel sheets. To investigate effect of surface roughness on weldability in prepared steels, electrode force was varied. Steel sheets (T-H) with high surface roughness ($Ra\;=\;1.94\;{\mu}m$) reduced electrode life. It was attributed to the higher contact resistance at the electrode-sheet interface in the presence of the high surface roughness. The increased electrode diameter decreased current density, therefore reducing weld electrode life due to small weld button size. When an increased electrode force was used, a significant increase in the electrode life was observed in welding of high surface roughness steel sheet. This study suggested that contact resistance at the electrode-sheet interface was the dominant factor, as compared to the sheet-sheet interface for determining electrode life in welding of surface roughness textured steel.

• 소성∙가공
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• 제23권5호
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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.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2001년도 춘계학술대회 논문집
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• pp.276-281
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• 2001

Wet Underwater arc welding process is inverstigated by using experimentally developed flux coated underwater arc welding electrode and SS400 steel plate of 12mm thickness as base metal. Two kinds of different flux covered wet arc welding electrode of 3.2mm diameter (UW-1, UW-2) are individually developed and one of the improved underwater welding electrode (UW-2) may be put to practical use for underwater arc welding process.

• Journal of Welding and Joining
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• 제30권6호
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• pp.49-55
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• 2012

The tandem welding process is one of the most efficient welding processes widely used in material joining technique such as manufacturing of strong and durable structures. It facilitates high rate of joint filling with little increase in the overall rate of heat input due to the simultaneous deposition from two electrode wires. The two electrodes in tandem welding process helps in high-efficiency and high productive of welding process. In this study a automated tandem welding system is developed to determine the correlation between cathode and anode and compared with current ratio of the two electrode torch. Three different inter-electrode distances were chosen, 25mm, 35mm and 45mm to perform the experiment with three different current ratio. From the experiment results, the current ratio between two torch has a large impact on width, height and depth of penetration. In addition, a stable bead geometry is obtained when inter-electrode distance is 35mm.