• 제목/요약/키워드: welding process

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CD 스터드 용접의 해석 및 결함 분석 Part 1 : 공정 모델링과 해석 (Analysis of CD Stud Welding Process and Defects Part 1: Process Modeling and Analysis)

  • 오현석;유중돈
    • Journal of Welding and Joining
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    • 제24권3호
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    • pp.34-41
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    • 2006
  • The CD (Capacitor Discharge) stud welding utilizes the arc heat and pressure to attach the stud to the workpiece, which consists of the arc. ignition, arcing and pressure welding stages. In order to predict the dynamic behavior of the CD stud welding process, mechanical and electrical models are employed in this work. While the mechanical model estimates the duration of each stage, the electrical model predicts the voltage and current waveforms using the RLC circuit. Effects of process parameters such as the electric components and spring force are analyzed through simulation. It is found that the contact resistance and gap between the stud and base metal influence the tip fusing and arcing duration. The calculated results showed reasonably good agreements with the experiment results.

연료탱크 제작시 시뮬레이션을 통한 용접변형 해석 (Analysis of Welding Distortion during the Production of Fuel Tanks for Excavators)

  • 양영수;김덕윤;배강열
    • 한국기계가공학회지
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    • 제15권6호
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    • pp.24-34
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    • 2016
  • To attach a fuel tank to an excavator, two sets of mounting plates on which three bosses are attached are welded onto the tank. In this study, the welding process of a fuel tank for an excavator was modeled using a finite element numerical method. The tank was modeled as a simple plate to which the mounting plate or bosses were attached by fillet welding. Thermal and thermo-elasto-plastic analyses of the welding process were carried out to predict the temperature distribution and material distortion during welding, respectively. Three different welding sequences for the tank were also modelled to compare the deformation that occurred due to each welding sequence. The results of the analysis predicted that changing the welding sequence around the mounting plate could not position the boss within the allowable dimensional range. The results also revealed the sequence in which the maximum distortion of the bosses welded onto the tank was 30% less than the maximum distortion due to the other sequences.

고에너지 열원에 따른 스테인리스강의 제살용접특성 비교 (Comparison on Autogenous Weldability of Stainless Steel using High Energy Heat Source)

  • 김종도;이창제;송무근
    • Journal of Advanced Marine Engineering and Technology
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    • 제36권8호
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    • pp.1076-1082
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    • 2012
  • 오늘날 LNG선의 용접에는 아크와 플라즈마가 사용되고 있으나 아크용접은 에너지 밀도가 낮아 후판에 대해서 다층용접이 불가피하며, 고밀도 열원인 레이저 용접에 비하여 용접속도에도 한계가 있다. 따라서 후판 용접시 다층용접에 의한 용접부의 조직적 결함이나 과대 입열로 형성된 열영향부 등의 문제를 해소하기 위하여 키홀용접에 의한 원패스 용접이 고려되고 있다. 키홀용접이 가능한 열원은 레이저, 전자빔, 플라즈마가 있으며, 현재 플라즈마 용접이 아크를 대체하여 LNG선 카고탱크의 멤브레인 용접에 적용되고 있다. 최근에는 멤브레인의 용접에 레이저를 적용하기 위한 많은 연구가 진행 중에 있다. 본 연구에서는 LNG선용 스테인리스강에 대한 파이버 레이저 및 플라즈마 아크 용접의 용접성, 기계적 성질 및 미세조직을 비교하였다. 그 결과 레이저 용접이 더 빠른 용접속도에서 좁은 용접부와 열영향부를 얻을 수 있었다. 따라서 LNG선의 용접에서는 파이버 레이저가 보다 우수한 용접법이라는 것을 알 수 있었다.

초내열합금의 대형마찰용접 공정해석 및 평가 (Evaluation and Process Analysis of the Superalloy Friction Welding for Large Shaft)

  • 정호승;김윤환;조종래;박희천;이낙규
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 2004년도 추계학술대회논문집
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    • pp.301-304
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    • 2004
  • Friction welding was used to weld the turbine wheel and shaft and have a good welding quality. Friction welding was conducted an the two dissimilar material, Nimonic 80A and SNCrW. The control of friction welding process parameter such as flywheel energy, interface temperature, amount of upset have an effect on the mechanical properties of the welded joint. FE simulation can be a useful tool to optimize the weld geometry and process parameters. Flash shape and thickness weld is consistent with the simulated results. Process analysis was performed by the commercial code DEFORM 2D. Mechanical property of weld joints was evaluated by microstructure, chemical component, tensile, impact, hardness test so on.

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자동차 차체 제조 공정에서 용접 공정 오류 검출을 위한 지능형 모니터링 시스템 개발 (Development of Intelligent Monitoring System for Welding Process Faults Detection in Auto Body Assembly)

  • 김태형;유지영;이세헌;박영환
    • Journal of Welding and Joining
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    • 제28권4호
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    • pp.81-86
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    • 2010
  • In resistance spot welding, regardless of the optimal condition, bad weld quality was still produced due to complicated manufacturing processes such as electrode wear, misalignment between the electrode and workpiece, poor part fit-up, and etc.. Therefore, the goal of this study was to measure the process signal which contains weld quality information, and to develop the process fault monitoring system. Welding force signal obtained through variety experimental conditions was analyzed and divided into three categories: good, shunt, and poor fit-up group. And then a monitoring algorithm made up of an artificial neural network that could estimate the process fault of each different category based on pattern was developed.

50kg급 고장력강 레이저용접부의 용접잔류응력 및 파괴인성 특성 (The Characteristic of Residual Stress and Fracture Toughness on The Welded Joint of HT50 by Laser Welding)

  • 노찬승;방한서;고민성;김성주;김하식
    • 한국해양공학회:학술대회논문집
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    • 한국해양공학회 2003년도 추계학술대회 논문집
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    • pp.93-96
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    • 2003
  • Laser beam welding process is a relatively new process in comparison with arc welding process, but it is expected to apply widely because of the many advantages, and research and development of that process is being progressed actively for the practical use. the application of this welding process has been restricted due to the high initial investment and the need of precise processing against the material, but cost reduction and thick plate welding in high speed have become practial by recent technological development, and this welding process to not only small parts in automobile, machinery and physicochemical field, but also a large structure and pipe line are being applied. In order to utilize this welding process appropriately to a steel structure, the properties of welding residual stresses and fracture toughness in welded joints are to be investigated for relibilty. On this study, after performing the finite element analysis, thermal and residual stress properties have been examined to the general structural steel (HT50) by laser beam welding. Besides, the property of fracture toughness has been investigated by the Charpy impact test and 3-points bending CTOD test carried out in the range of temperature between $-60^{\circ}C$ and $20^{\circ}C$. From the research results it is revealed that the maximum residual stress appears in the center of plate thickness and the fracture toughness is influenced by strength mis-match.

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PLACKETT-BURMAN MODEL을 이용한 Cu-Ni합금의 PULSE MIG 용접 변수해석 (Application of Plackett-Burman model in welding experiments : effects of welding parameters on bead shape in Cu-Ni PULSE MIG process)

  • 문영훈;이기학;허성도
    • Journal of Welding and Joining
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    • 제5권4호
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    • pp.47-53
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    • 1987
  • The purpose of this study is to reexamine our test method in the light ofstatistical methods for data interpretation. Our trial to apply Plackett-Burman statistical model in multifactorial welding experiments shows that is saves much time and cost and extracts very accurate results. In this study, the parametric effects of bead shape on pulse MIG process in Cu-Ni alloy are investigated for verifying our trial.

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유전자 알고리즘을 이용한 GMA 필릿 용접 비드형상 예측에 관한 연구 (A Study on Bead Geometry Prediction the GMA Fillet Welding using Genetic Algorithm)

  • 김영수;김일수;이지혜;정성명;이종표;박민호
    • Journal of Welding and Joining
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    • 제30권6호
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    • pp.126-132
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    • 2012
  • The GMA welding process involves large number of interdependent variables which may affect product quality, productivity and cost effectiveness. The relationships between process parameters for a fillet joint and bead geometry are complex because a number of process parameters are involved. To make the automated GMA welding, a method that predicts bead geometry and accomplishes the desired mechanical properties of the weldment should be developed. The developed method should also cover a wide range of material thicknesses and be applicable for all welding position. For the automatic welding system, the data must be available in the form of mathematical equations. In this study a new intelligent model with genetic algorithm has been proposed to investigate interrelationships between welding parameters and bead geometry for the automated GMA welding process. Through the developed model, the correlation between process parameters and bead geometry obtained from the actual experimental results, predicts that data did not show much of a difference, which means that it is quite suitable for the developed genetic algorithm. Progress to be able to control the process parameters in order to obtain the desired bead shape, as well as the systematic study of the genetic algorithm was developed on the basis of the data obtained through the experiments in this study can be applied. In addition, the developed genetic algorithm has the ability to predict the bead shape of the experimental results with satisfactory accuracy.

탠덤 GMAW의 품질확보를 위한 용접이음부위의 성능평가에 대한 연구 (A Study on the Performance Evaluation of the Welded Joint to Maintain the Quality of the Tandem GMAW)

  • 박철균;이종표;박민호;김일수
    • Journal of Advanced Marine Engineering and Technology
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    • 제39권3호
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    • pp.230-237
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    • 2015
  • 산업의 생산성 향상 및 용접공정의 개선을 위해 용접공정에 탠덤 용접의 적용가능성을 확인하고자 실험을 통한 용접이음부위의 성능평가를 실시하였다. 1전극 용접과 탠덤 용접의 실험을 통해, 비드의 형상을 비교 분석하고, 용접실험의 결과시험편에 대하여 3가지 시험(인장시험, 경도시험, 굽힘시험)을 실시하였다. 또한 결과시험편에 대한 기계적 성질을 분석하여 탠덤 용접이음부위에 대한 성능평가를 수행 하였다. 본 연구는 탐뎀 용접이음부위에 대한 기계적 성질 및 안전강도 보증을 목적으로 하고 있으며, 인장시험, 굽힘시험 및 경도시험을 통해 탠덤 GMAW 의 신뢰성과 효율성을 확인하고자 한다.

오스테나이트계 스테인리스강과 SM45C의 연속파형 Nd:YAG 레이저 용접특성비교 (Comparison of Welding Characteristics of Austenitic 304 Stainless Steel and SM45C Using a Continuous Wave Nd:YAG Laser)

  • 유영태;오용석;노경보;임기건
    • 한국공작기계학회논문집
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    • 제12권3호
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    • pp.58-67
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    • 2003
  • Welding characteristics of austienite 304 stainless and SM45C using a continuous wave Nd:YAG laser n experimentally investigated Laser beam welding is increasingly being used in welding of structural steels. The laser welding process is one of the most advanced manufacturing technologies owing to its high speed and deep penetration. The thermal cycles associated with laser welding are generally much Inter than those involved in conventional welding processes, leading to a rather small weld zone. Experiments are performed for 304 stainless steel plates changing several process parameter such as laser power, welding speed, shielding gas flow rate, presence of surface pollution, with fixed or variable gap and misalignment between the similar and dissimilar and plates, etc. The Nd:YAG laser welding process is one of the most advanced manufacturing technologies owing to its high speed and penetration. This paper describes the weld ability of SM45C carbon steel for machine structural use by Nd:YAG laser. The follow conclusions can be drawn that laser power and welding speed have a pronounced effect on size and shape of the fusion zone. Increase in welding speed resulted in an increase in weld depth/aspect ratio and hence a decrease in the fusion zone size. The penetration depth increased with the increase in laser power.