• Journal of Welding and Joining
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• 제16권6호
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• pp.52-58
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• 1998

The effect of Si content in welding wires on th arc stability was investigate, in the region of short circuit transfer and spray transfer. In the region of short circuit transfer, with increasing Si content, average arcing time and average short circuit time were increased. Therefore, droplet transfer frequency was decreased, due to the increase of arcing time and peak current at the moment of arc-reiginition was increased, due to the increase of short circuit time. In the region of spray transfer, the fluctuations of arc current and arc voltage was the most stable in wire with Si content of about 00.60 wt.%.

• Journal of Welding and Joining
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• 제17권1호
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• pp.55-61
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• 1999

The effect of S content in welding wires on the arc stability was investigated, in the region of short circuit transfer and spray transfer. In the region of short circuit transfer, with increasing S content, average arcing time and average short circuit time were decreased. Therefore, droplet transfer frequency was increased, due to the reduction of arcing time and peak current at the moment of arc-reiginition was decreased, due to the decrease of short circuit time. In the region of spray transfer, the fluctuation degree of arc current and arc voltage became more stable, with increasing S content.

• Journal of Welding and Joining
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• 제12권4호
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• pp.76-84
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• 1994

Droplet transfer modes due to welding conditions and the effect of Ca in welding wire on droplet transfer were investigated. Droplet transfer mode in CO$_{2}$ welding was classified into 2 modes, that is, short circuit and globular transfer, with increasing welding current and voltage. With increasing Ca content in wire, repulsive pressure due to vaporization of Ca was considerably increased. In short circuit transfer region, arcing time was increased and droplet transfer cycle was decreased, with increasing Ca content. In globular transfer region, welding condition for globular transfer was lower current region, with increasing Ca content.

• Journal of Welding and Joining
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• 제14권5호
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• pp.106-112
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• 1996

The effects of Ti addition in welding wire on the spatter generation and the droplet transfer phenomena were investigated. With increasing Ti content the spattering rate was decreased but the ratio of large size spatter (D $\geq$ 1. 0mm) was increased in both short circuit and globular transfer mode of $CO_2$welding. In short circuit transfer region, the arcing time was increased and the droplet transfer frequency was decreased with increasing Ti content In globular transfer region, the transition current and voltage to globular transfer was lowered and the welding condition region for stable globular transfer was widened with increasing Ti content.

• Journal of Welding and Joining
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• 제19권6호
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• pp.630-635
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• 2001

The characteristics of spatter generation in the short circuit transfer region of $CO_2$ welding was investigated. Spatteriing phenomena could be classified into three types : Type I generated due to the abrupt increase of arc voltage in arcing duration. Type II by the gas ejection from molten metal and Type III generated by the arc instability at the moment of arc re-ignition just after short circuiting. Main observed types were dependent on the chemical composition of welding wires. The case of YCW12 wires was mainly composed of spatters generated by Type l and Type II, while most, spatters in YCW11 wires were generated by Type II and Type III.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1998년도 전력전자학술대회 논문집
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• pp.166-170
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• 1998

The metal transfer of CO2 arc welding machine can be devided into short-circuit(low current) metal transfer. Especially in large crrent region, the main problem of CO2 arc welding machine is much spatter generation which is caused by mainly instant short-circuit matal transfer. So in this paper descrives new current control method in large current region, which can improve welding performance and lessen spatter generation. And as a result of experiment, the effect of proposed control method is demonstrated.

• Journal of Welding and Joining
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• 제17권3호
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• pp.36-43
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• 1999

The effect of Si content in welding wires on spattering characteristics and droplet transfer phenomena was studied. In MAG welding using 80% Ar-20% $CO_2$ shielding gas, spattering characteristics and droplet transfer phenomena were varied with Si content of wire. With increasing Si content, the spattering ratio and the ratio of large size spatter $(d\geq1.0mm)$ were increased. The increase of Si content in molten metal made surface tension increase due to reduction of oxygen content, which resulted from deoxidizing action of silicon. The increase of surface tension resulted in unstable transfer phenomena and arc instability in both short circuit and spray region. With changing Si content of wire, spattering characteristics and droplet transfer phenomena was directly influenced by the variation of surface tension, compared with the effect of arc stability.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2001년도 추계학술발표대회 개요집
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• pp.60-61
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• 2001

• 대한기계학회논문집A
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• 제24권8호
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• pp.1885-1898
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• 2000

Welding quality is closely related to the arc state. So, it is very important to estimate the arc state in real time. In the short circuit transfer region of CO2 are welding, the spatter , as it is well known, is mainly generated on an instance of short circuit or on an instance that the are is ignited after short circuit, or on the cases of an instantaneous short circuit. If the short circuit period or the arc time is irregular, the spatter is generated more than it is regular. Thus there is a close relationship of the amount of the spatter generation with the arc stability. In this paper, to develop the index for estimating the arc stability in short circuit transfer range Of CO2 arc welding, the welding current and are voltage waveforms were measured and the spatter generated was captured and measured. The correlation analysis of the measured amount of the spatter with the factors (the components and the standard deviations of the components) was performed, and the factors that have a considerable influence on the spatter generation among all factors were selected. And some cases of models consisted of the factors were presented, and a mathematical index model which can make an estimation the amount of the spatter from these models with multiple regression analysis. Also, it was compared how much the amount of the spatter generated under the selected welding conditions do these index models fit, and the index model to estimate the arc stability which represent the spatter generation most appropriately was developed

• Journal of Welding and Joining
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• 제25권5호
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• pp.58-63
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• 2007

The relationship between GMA welding conditions and the bead shape of overlay weld was studied by using ${\Phi}1.6mm$ hypo-eutectic metal-cored wire designed for hardfacing against the severe metal-to-metal wear. As the welding voltage increased, the dilution also increased but the sudden drop of dilution was observed at $30{\sim}33V$. It was considered to be due to the decrease of penetration resulting from the change of transfer mode, from short circuit to spray. It was also found that the behavior of penetration with welding current was dependant on the transfer mode. The short circuit mode exerted the penetration to decrease while the spray mode did it to increase with increase of welding current. The former was considered to be responsible for the remarkable decrease in dilution at low welding voltage region. The change of transfer mode also had an effect on the behavior of bead width with welding current but it did not on the bead spreadability defined as W/H ratio. It was considered that the optimal welding conditions for multi-pass overlay welding could be obtained from the bead spreadability suitable for bead lapping and the dilution as low as possible in the spray transfer mode.