• Journal of Welding and Joining
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• v.14 no.3
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• pp.2-11
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• 1996

용접 능률과 품질에 영향을 미치는 여러가지 요인들 중에서 용접기의 성능은 가장 중요한 요소의 하나이다. 이러한 점에서 숙련도에 주로 의존하던 종래의 용접성 에 대한 관념이 바뀌어야 하며, 품질 표준화 작업의 일환으로 용접기 제어 성능의 향상도 절실하다고 하겠다. 용접품질의 제어성능에 직접 영향을 주는 요소가 무엇인지 를 생각해 볼때, 그것은 바로 용접부에 공급되는 에너지의 제어, 용접 물리현상의 이해와 관찰을 기초로 적절한 함수의 설정과 함께 이들의 관리가 필요함을 알게된다. system화된 용접기는 이들 용접의 물리적 현상과 그 해석 결과를 어떤 방식으로든 이용하고 제어하여야 할 것이므로, 용접기 전력제어의 중요성과 함께 제어 소자의 성능은 물론 제어 algorithm의 최적화가 필수 요소임을 실감하게 된다. 따라서, 여기 에서는 제조 공정에서 가장 중요한 용접 공정의 하나인 아크 용접(GMAW, GTAW) system 의 개요와 특성 및 향후 기술개발의 과제에 대하여 기술하고자 한다.

• Journal of Welding and Joining
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• v.34 no.4
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• pp.48-54
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• 2016

The use of Zn coated steel has increased in the automotive industry due to its excellent corrosion resistance. Conventionally the BIW(body-in-white) structure and the hang-on parts have been made of Zn coated steel and more recently Zn coated steel began to be applied in the chassis parts. During gas metal arc (GMA) welding of the chassis part, lap fillet joint used to be adopted but spatter generation and porosities are most important concerns. In the industrial applications, an intentional joint gap was made to avoid the weld defects but it is not easy to control the size of joint gap. In this research, gas tungsten arc (GTA) is combined with GMA welding where GTA precedes GMA. As pulsed arc was adopted as GMA, GTA was oscillated along the longitudinal direction by pulsing GMA, but the arc oscillation did not disturb the molten droplet transfer of GMA welding. By increasing the distance between GTA and GMA, the length of weld pool increased and porosity could be reduced. Moreover porosity in the welds was fully removed when the distance between two arcs was 15 mm.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.5
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• pp.2019-2024
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• 2011

The effect of the wear of contact tips on the weld beads made by a Gas Metal Arc Welding(GMAW) process was studied. In order to correlate between the wear of tips and beads, the droplet transfer was investigated by a high speed camera and waveform shapes, and the condition of beads was examined by a low magnification camera as well. It was found that the worn contact tip had caused to shift the contact point between the tip and the welding wire which resulted in nonuniform beads. In addition, the worn contact tip had changed the welding resistance and brought about the arc instability during welding.

• Proceedings of the KWS Conference
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• 2009.11a
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• pp.50-50
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• 2009

본 연구에서는 차체 부품의 경량소재 대체에 따른 Panel Assembly Rear Seat Back 부품 제작에 최신 저입열 미그용접공정을 적용한 TWB(Tailor Welded Blank) 공정기술을 확보하기 위해 최적 용접조건 도출에 관한 연구를 진행하였다. 용접 후 성형이 이뤄지는 제조공정의 특성 상 성형강도에 중점을 둔 실험을 진행하였으며, 이를 위해 각 와이어에 따른 용접부의 기계/금속학적 특성이 평가되었다. 대상 시편은 6천계열 열처리형 합금이며, 두께는 각각 1.6t, 1.4t로 이를 맞대기 용접 후 그 특성을 평가하였다. 용접은 저입열 GMA용접 공법 중 하나인 CMT 용접법(Cold Metal Transfer)을 사용하였으며, 평가 대상 와이어로는 4043, 4047, 5183 및 5356이 사용되었다. 특성평가는 마크로 및 마이크로 조직, 경도, 인장강도, 기공 및 결함, 성형강도 등에 대해 이뤄졌으며, 희석된 와이어의 조성이 용접부 특성에 미치는 영향에 대해서도 검토되었다. 실험 결과, 5천계열 와이어가 성형강도에 비교적 더 강인한 결과를 나타냈으며 성형강도는 용접조건 및 초기 갭에 대한 영향은 받았으나, 비드형상과 강도간의 연관성은 찾을 수 없었다. 이에 따라 TWB 적용을 위한 와이어로는 5356이 가장 우수한 것으로 판명되었다.

• Journal of Welding and Joining
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• v.28 no.6
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• pp.58-62
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• 2010

In this study, the bead-on-plate welding were conducted by using GMA welding and plasma-GMA welding on Al 5052 and, Al 6061 plates. For these processes, the maximum welding speeds for full penetration were compared, and various weld qualities such as bead appearance, cross-section, cracks and porosities were examined. Faster welding speed, cleaner bead surface and more stable drop transfer could be achieved by plasma-GMA welding, compared with GMA welding.

• Proceedings of the KWS Conference
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• 2002.05a
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• pp.68-70
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• 2002

A CCD camera with a laser strip was applied to realize the automation of welding process in GMAW. The Hough transformation was used to extract the laser stripe and to obtain specific weld points. In this study, a neural network based on the generalized delta rule algorithm was adapted for the process control of GMA, such as welding speed, arc voltage and wire feeding speed.

• Journal of the Korean Society of Mechanical Technology
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• v.13 no.1
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• pp.17-22
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• 2011

As the quality of a weld joint is strongly influenced by process parameters the welding process, an intelligent algorithms that can predict the bead geometry and shape to accomplish the desired mechanical properties of the weldment should be developed. In this study, prepared by ${\Phi}1.6mm$ GMA welding of metal wire nose Advice jowelui 350A 600A grade level inverter welder and DAIHEN SCR's were carried out using welding. Welding conditions were 5.5m/min wire feed rate the welding current is rapidly transmit approximately 260A, welding voltage was about 30V. CTWD a 22mm, shielding gas was Ar 20L/min and the welding speed was a 240mm/min. Using data collected during welding equipment welding current and welding voltage waveform was analyzed by measuring the volume of the transition mode. Addition of $CaCO_3$ as a loss of the spread of the weld bead dilution rate decreased, suggesting that, GMA in the overlay welding bead shape control, dilution control and may be used as a welding flux is considered. Stabilizing effect of the arc by the Ca-containing $CaF_2$, $CaCO_3$, $CaMg(CO_3)_2$, respectively, welding flux 0.1wt.% added GMA welding and weld overlay were evaluated with dilution, $CaF_2$, and $CaMg(CO_3)_2$ added to the dilution of Seemed to increase.

• Proceedings of the KWS Conference
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• 2009.11a
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• pp.31-31
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• 2009

최근 전세계적으로 유가상승 및 환경에 대한 관심이 증대되면서 자동차 업계에서는 차량 경량화를 통한 연비향상에 대한 연구가 활발히 진행되고 있다. 대표적인 기술개발 사례로서 초경량 철강 차체의 개발을 들 수 있다. 이는 고장력강을 적용함으로써 강성을 증대시킴과 동시에 두께감소에 의한 경량화를 이루고자 추진되고 있다. 하지만 고장력강은 자체의 높은 강성을 지니고 있는 반면, 일반 강종에 비해서 스프링백이 크고 용접성도 많이 떨어지는 제약을 안고 있다. 아크 용접법 중 하나인 AC pulse MIG 용접은 DCEP (direct current electrode positive) 와 DCEN (direct current electrode positive) 구간이 주기적으로 반복하는 용접법으로 스패터 발생이 거의 없으며 특히 갭 접합성이 우수하여 자동차 차체 조립공정에 적용되고 있다. 본 연구에서는 자동차 차체용 AHSS 소재의 겹치기 용접 실험을 통해 실제 생산라인에서 용접 이음부에 발생되는 갭에 대해 강건한 용접 공정 조건을 제시하였다. 먼저 고속카메라 촬영을 통해 AC pulse MIG 용접에서 EN ratio 변화에 따른 와이어 용융현상을 분석 하였으며 단면마크로, 인장시험, 인장 파단면 분석을 통해 겹치기 용접에서 0~2mm 사이의 갭 발생에 강건한 용접 조선을 제시하였다.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.1408-1411
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• 1996

In arc welding processes, because of the complexity and nonlinearity of heat transfer phenomena, it is often difficult to design an effective control system based upon an exact mathematic model. In this paper, we simulated the welding process for various welding conditions and positions to investigate the variations of temperature distribution for those cases. Those will be used as a preinformation for developing quality control system for arc welding process.

• Proceedings of the KWS Conference
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• 1996.10a
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• pp.148-152
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• 1996

A transient two-dimensional (2D) model was developed for investigating the heat and fluid flow in old pools and determining velocity profile and temperature distribution for the Gas Metal Arc (GMA) welding process. The mathematical formulation deals with the driving farces (electromagnetic, buoyancy, surface tension and plasma drag forces) as well as energy exchange between the molten filler metal droplet and weld pools. A general thermofluid-mechanics computer program, PHOENICS, was employed to numerically solve the governing equation with the associated source terms. The results of computation have shown that the electromagnetic and surface tension farces as will as the molten filler metal droplet have major influence in shaping the weld pool geometry.