• 한국디지털건축인테리어학회논문집
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• 제8권1호
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• pp.57-64
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• 2008

There are many problems in present truss-deck slab system for example welding defect, segregation, water leakage, rust and tarnish etc. These problems may be caused by spot welding thin galvanized steel plate and lattice bar. The TOX Joining Systems is to join metal sheets of different material and thickness with and without coating or painting without adding heat or a joining part. Newly developed TOX-deck slab system using non-welding joint is free from above mentioned problems. The objects of this study are suggestion of design strength of TOX joint by experimental and statistical analyses and development of window based program to design the TOX-deck slab system.

• 한국자동차공학회논문집
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• 제6권5호
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• pp.10-19
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• 1998

The erosion of electrode in spot welding of aluminium alloy by direct current is dependent on the electric polarity. The positive electrode is much more eroded than the negative one. To explain this phenomenon, Peltier effect has been generally accepted as a unique theory. In this study Peltier effect was evaluated by calculations on the basis of some references and experiments. The difference of heat generated by Peltier effect on both electrode surfaces was, however, only 4% of total heat generated during wel- ding. Because of insufficient explanation, Kohler theory, which is mainly affected by thin oxide film, was introduced. A theoretical calculation showed 17% of the temperature difference between the positive and negative electrode, in case "surface voltage" resulted from oxide film was 30% of total contact voltage. This revealed that the erosion of electrode could be more affected by Kohler theory than effect.an effect.

• 한국생산제조학회지
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• 제21권4호
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• pp.547-555
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• 2012

This paper focuses on the research of the anode and cathode in the Ni-MH secondary battery. In this paper, the proposed method employs a continuous wave Nd : YAG laser based on the pure Ni instead of the low carbon steel to improve the conductivity although the conventional secondary battery is based on the resistance spot welded with low carbon steel SS41. It welds a sandwich panel using the pure Ni and the porous thin plate, and the tested optimal conditions for the laser power and irradiation speed were 300 and 350 Watt, and 1.0~1.6m/min, respectively. Finally, we observed a ratio, heat input and cross-section and measured the conductivity of the welding section to test the weldability.

• 한국레이저가공학회지
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• 제8권1호
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• pp.27-37
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• 2005

During laser spot welding of the braun tube electron gun, phenomena such as serious spattering and oxidative reaction, etc. were occurred. The spatter occurred from weld pool affects the braun tube, namely it blocks up a very small hole on the shadow mask and causes short circuit between two poles of the electron gun. We guessed that high power density and oxidative reaction are main sources of these problems. So, we studied to prevent and to reduce spatter occurring in spot welding of the braun tube electron gun using pulsed Nd:YAG laser. The characteristics of laser output power was estimated, and the loss of laser energy by optical parameter and spatter was measured by powermeter. The effects of welding parameters, laser defocused distance and incident angle, were investigated on the shape and penetration depth of the laser welded bead in flare and flange joints. From these results, the laser peak power was a major factor to control penetration depth and to occur spatter. It was found that the losses of laser energy by optic parameter and sticked spatter affect seriously laser weldability of thin sheets.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 1996년도 특별강연 및 춘계학술발표 개요집
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• pp.183-185
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• 1996

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2001년도 춘계학술발표대회 개요집
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• pp.186-188
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• 2001

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2005년도 춘계학술발표대회 개요집
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• pp.285-287
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• 2005

During fabrication of deck house block in passenger ships, the problem of unexpected large deformation and distortion frequently occurs. In this case, line and spot heating method were widely used to correct the distortion of thin plate structure. Spot heating was especially used for the case under 5mm thickness. Few papers are available on the working conditions of spot heating method but only little information on deformation control. In this study, evaluation was carried out on the temperature distribution of spot heating methods using FEA and practical experiments for various heating time. IIn FEA, heat input model was established using Tsuji's double Gaussian heat input mode (Tsuji, I., 1988). This model was verified by comparing with experimental data. Also radial shrinkage and angular distortion due to spot heating were determined and compared with experimental results. Thermo elasto-plastic analysis was performed using commercial FE code, MSC/MARC. Radial shrinkage and angular distortion were measured using 3D measuring apparatus. Based on these results, simplified analysis model for deformation by spot heating was established.

• Journal of Welding and Joining
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• 제20권4호
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• pp.525-534
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• 2002

During laser spot welding of the braun tube electron gun, phenomena such as serious spattering and oxidative reaction, etc. were occurred. The spatter occurred from weld pool affects the braun tube, namely it blocks up a very small hole on the shadow mask and causes short circuit between two roles of the electron gun. We guessed that high power density and oxidative reaction are main sources of these problems. So, we studied to prevent and to reduce spatter occurring in spot welding of the braun tube electron gun using pulsed Nd:YAG laser. The characteristics of laser output power was estimated, and the loss of laser energy by optical parameter and spatter was measured by powermeter. The effects of welding parameters, laser defocused distance and incident angle, were investigated on the shape and penetration depth of the laser welded bead in flare and flange joints. From these results, the laser peak power was a major factor to control penetration depth and to occur spatter. It was found that the losses of laser energy by optic parameter and sticked spatter affect seriously laser weldability of thin sheets. The deepest penetration depth is gotten on focal position, and a "bead transition" occurred with a slight displacement of focal position relative to the workpiece surface and the absorption rate of the laser energy is affected by the shape factor of the workpiece. When we changed the incident angle of laser beam, the penetration depth was decreased a little with increasing of the incident angle, and the bead width was increased. The spattering was prevented by considering laser beam energy and incident angle.ent angle.

• 한국정밀공학회지
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• 제16권1호통권94호
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• pp.132-140
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• 1999

This paper suggests a monitoring method for the pulsed laser spot welding of the thin metal sheets using a point IR(InfraRed) sensor. A new criterion was introduced and the experimental results guaranteed the efficiency. The ideal radiation feature was derived from the mathematical model and was simulated. The radiation feature is robust to withstand the change of measuring condition and can be used to detect the absorbed laser energy. In an experiment, the radiation feature was examined for the differect laser energy. The pulse width and the laser power was variated and the radiation feature was examined. In the other experiment, the relationship between the weld strength and radiation feature was examined. Artificial Neural Network(ANN) was employed to find out the relationship. The correlation coefficient between the real strength and the estimated strength is high as 0.94 and the mean square error is low as 0.64 kgf learned parts. Another group of the welds was used to appraise the learning efficiency. The correlation coefficient between the measured and the estimated weld strength is high as 0.91.

• 대한기계학회논문집
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• 제7권3호
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• pp.313-318
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• 1983

It is required in designing a spot welding to get in advance an estimated figure of nugget diameter. A method of estimating nugget diameter of low carbon steel sheets is suggested in tesms of utilizing elastic calculation in theory and of making a sectional observation of specimen of spot welding in experiment. The resultant findings are summarized as follows: 1) A contact diameter of sheet, 2.gamma.$_{o}$=d sub e/+(1.1)t, wheer de is the electrode tip diameter and t is the thickness of sheets. 2) The practical measurement of the nugget diameter reveals that $d_{n}$=(1.05) $d_{e}$+(0.9)t, and $d_{b}$ is less by 0.8-4.3% than 2.gamma.$_{o}$. 3) The more $d_{n}$ is as compared with t, the less the difference between a theoretical value and an experimental value is. 4) In the spot welding of thin steel sheets less than 3mm in thickness that are commonly used in sheet metal works, the contact diameter equals the nugget diameter. In this case, either the theoretical or experimental approach can be used for estimating the nugget diameter.meter.ter.r.