• Title/Summary/Keyword: Surface Bead Width

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A study on the monitoring and control of the back bead width in arc welding with consumable blectrode (소모성 전극의 아크 용접에서 이면비-드 폭의 모니터링과 제어에 관한 연구)

  • 부광석;오준호;조형석
    • 제어로봇시스템학회:학술대회논문집
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    • 1987.10b
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    • pp.329-334
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    • 1987
  • The purpose of this study is to monitor and control the back bead width in arc welding with consumable electrode for reduction of the occurrence of weld defect. The temperature of a point on the weldment surface is selected, as a monitoring parameter, and measured by an optical infra-red sensor. The correlation between the back bead width and the surface temperature is experimentally obtained for various thicknesses of the weldment. The welding travel speed and the surface temperature are taken, respectively, as an input and an output of the welding process under the stable condition of arc. A PI control scheme to maintain the surface temperature at the desired level is proposed by the experimental study.

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Selection of Optimal Welding Condition in Root-pass Welding of V-groove Butt Joint (맞대기 V-그루브 이음 초층 용접에서 최적의 용접조건 선정)

  • Yun, Seok-Chul;Kim, Jae-Woong
    • Journal of Welding and Joining
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    • v.27 no.1
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    • pp.95-101
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    • 2009
  • In case of manufacturing the high quality welds or pipeline, the full penetration weld has to be made along the weld joint. Thus the root pass welding is very important and has to be selected carefully. In this study, an experimental method for the selection of optimal welding condition was proposed in the root pass welding which was done along the V-grooved butt weld joint. This method uses the response surface analysis in which the width and height of back bead were chosen as the quality variables of the weld. The overall desirability function, which is the combined desirability function for the two quality variables, was used as the objective function for getting the optimal welding condition. In the experiments, the target values of the back bead width and the height are 6mm and zero respectively for the V-grooved butt weld joint of 8mm thickness mild steel. The optimal welding conditions could predict the back bead profile(bead width and height) as 6.003mm and -0.003mm. From a series of welding test, it was revealed that a uniform and full penetration weld bead can be obtained by adopting the optimal welding condition which was determined according to the method proposed.

Three-dimensional numerical simulation for the prediction of product shape in sheet casting process

  • Chae, Kyung-Sun;Lee, Mi-Hye;Lee, Seong-Jae;Lee, Seung-Jong
    • Korea-Australia Rheology Journal
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    • v.12 no.2
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    • pp.107-117
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    • 2000
  • Prediction of the product shape in sheet casting process is performed from the numerical simulation. A three-dimensional finite element method is used to investigate the flow behavior and to examine the effects of processing conditions on the sheet produced. Effects of inertia, gravity, surface tension and non-Newtonian viscosity on the thickness profile of the sheet are considered since the edge bead and the flow patterns in the chill roll region have great influence on the quality of the products. In the numerical simulation with free surface flows, the spine method is adopted to update the free surface, and the force-free boundary condition is imposed along the take-up plane to avoid severe singularity problems existing at the take-up plane. From the numerical results of steady isothermal flows of a generalized Newtonian fluid, it is shown that the draw ratio plays a major role in predicting the shape of the final sheet produced and the surface tension has considerable effect on the bead thickness ratio and the bead width fraction, while shear-thinning and/or tension-thickening viscosity affect the degree of neck-in.

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Selection of an Optimal Welding Condition for Back Bead Formation in GMA Root Pass Welding (GMA 초층용접에서 이면비드 생성을 위한 최적용접조건의 선정)

  • Yun, Young-Kil;Kim, Jae-Woong;Yun, Seok-Chul
    • Journal of Welding and Joining
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    • v.28 no.5
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    • pp.86-92
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    • 2010
  • In GMAW processes, bead geometry is a criterion to estimate welding quality. Bead geometry is affected by welding current, arc voltage, welding speed, shielding gas and so on. Thus the welding condition has to be selected carefully. In this paper, an experimental method for the selection of optimal welding condition was proposed in the root pass welding which was done along the GMA V-grooved butt weld joint. This method uses the response surface analysis in which the width and height of back bead were chosen as the quality variables of the weld. The overall desirability function, which is the combined desirability function for the two quality variables, was used as the objective function for getting the optimal welding condition. Through the experiments, the target values of the back bead width and the height were chosen as 4mm and 1mm respectively for the V-grooved butt weld joint. From a series of welding test, it was revealed that a uniform weld bead can be obtained by adopting the optimal welding condition which was determined according to the method proposed.

A Study on the Optimal Welding Condition for Root-Pass in Horizontal Butt-Joint TIG Welding (수평자세 맞대기 TIG 초층용접에서 최적용접조건의 선정에 관한 연구)

  • Jung, Sung Hun;Kim, Jae-Woong
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.41 no.4
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    • pp.321-327
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    • 2017
  • In this study, to investigate the shape of the back bead as a weld quality parameter and to select the optimal condition of the root-pass TIG welding of a horizontal butt-joint, an experimental design and the response surface method (RSM) have been employed. Three parameters are used as input variables, which include the base current, peak current, and welding speed. The back bead width is selected as an output variable representing the weld quality, the target value of the width is 5.4 mm. Conducting the experiments according to the Box-Behnken experimental design, a $2^{nd}$ regression model for the back bead width was made, and the validation of the model was confirmed by using the F-test. The desirability function was designed through the nominal-the-best formula for the appropriate back bead width. Finally, the following optimal condition for welding was selected using the RSM: base current of 0.9204, peak current of 0.8676, and welding speed of 0.3776 in coded values. For verification, a test welding process under the optimal condition was executed and the result showed the back bead width of 5.38 mm that matched the target value well.

A study on the Optimum Conditions of Nd:YAG LBW for Zircaloy-4 End Cap Closure By Optical Fiber Transmission (광섬유전송에 의한 Zircaloy-4 봉단마개밀봉의 Nd:YAG LBW의 최적조건에 관한 연구)

  • 김수성;김웅기;이영호
    • Journal of Welding and Joining
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    • v.15 no.6
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    • pp.85-95
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    • 1997
  • This study is to investigate the optimum conditions of Nd:YAG laser beam welding for Zircaloy-4 end cap closure by optical fiber transmission. Laser welding parameters which affect the penetration depth and bead width were experimentally examined using the various beam radius by the beam quality analyzer, joint geometries of end cap and the laser parameters which mean pulse width, repetition rate and pulse energy. Also, an optimum welding speed and the effect of assistant gas with varying the flow rate of He were investigated. We found that the laser average power for the end cap welding will be 230W and rotation speed must not exceed 8 RPM, the best position of focus using optical fiber with 600.mu.m will be 2 to 3mm below the surface of the material.

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A Study of the Infrared Temperature Sensing System for Surface Temperature Measurement in Laser Welding(I) - Surface Temperature Profile According to Bead Shape - (레이저용접부 온도측정을 위한 적외선 온도측정장치의 개발에 관한 연구(I) -용융부 형상에 따른 표면온도분포-)

  • 이목영;김재웅
    • Journal of Welding and Joining
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    • v.20 no.1
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    • pp.62-68
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    • 2002
  • This study investigated the feasibility of penetration depth measurement using infrared temperature sensing on the weld surface. The detection point was optimized by FEM analysis in the laser keyhole welding. The profile of the weld surface temperature was measured using infrared detector array. Surface temperature behind the weld pool is proportional or exponentially proportional to penetration depth and bead width. From the results, the monitoring device of surface temperature using infrared detector array was applicable fur real time penetration depth control.

A Study of the Infrared Temperature Sensing System far Measuring Surface Temperature in Laser Welding(II) - Effect of the System Parameter on Infrared Temperature Measurement - (레이저용접부 온도측정을 위한 적외선 온도측정장치의 개발에 관한 연구 (II) - 적외선 온도측정에서 제인자의 영향 -)

  • 이목영;김재웅
    • Journal of Welding and Joining
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    • v.20 no.1
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    • pp.69-75
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    • 2002
  • This study investigated the effect of the system parameters on penetration depth measurement using infrared temperature sensing system. The distance from focusing lens to detector was varied to diminish the error in measuring weld bead width. The effect of bead surface shape on measured surface temperature profile was evaluated using specimen heated by electric resistance. The measuring distance from laser beam was changed to optimize the measuring point. The results indicated that the monitoring device of surface temperature using infrared detector array was applicable to real time penetration depth control.

Development of Automatic Filet Welding Torch System with High Speed Rotating Arc Sensor

  • Lee, W.K.;Lee, G.Y.;Kim, J.H.;Kim, S.B.
    • 제어로봇시스템학회:학술대회논문집
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    • 2001.10a
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    • pp.94.1-94
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    • 2001
  • Arc sensor gives important groove information during welding. Automatic seam tracking control system with arc sensor has significant characteristics such that bead formation is given as decentralization of penetration and formation of concave bead profile and that a turning point of transverse weaving with constant arc length control is decided whether or not torch height reaches to a specified setting level. Furthermore, the rotating action of the arc prevents hanging of weld bead and forms flat bead surface under high speed welding condition. The variation of groove and deposition area can be detected from the trace of weaving. The area and width of weaving trace has close correlation with the area of groove and deposition. In this paper, main object of this system is to realize an adaptive microprocessor based controller ...

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ANALYSIS OF TRANSIENT TEMPERATURE DISTRIBUTION IN ROTATING ARC GMA ELDING BY CONSIDERING DROPLET DEFLECTION

  • Kim, Cheolhee;Na, Suck-Joo
    • Proceedings of the KWS Conference
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    • 2002.10a
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    • pp.763-768
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    • 2002
  • This paper presents a mathematical model predicting the temperature distribution in rotating GMA welding. The bead width increases with rotation frequency at the same rotation diameter because the molten droplets are deflected by centrifugal force. The numerical solution is obtained by solving the transient three-dimensional heat conduction equation considering the heat input from the welding arc, cathode heating and molten droplets. Generally in GMA welding the heat input may be assumed as a normally distributed source, but the droplet deflection causes some changes in the heat input distribution. To estimate the heat flux distribution due to the molten droplet, the contact point where the droplet is transferred on the weld pool surface is calculated from the flight trajectory of the droplets under the arc plasma velocity field obtained from the arc plasma analysis. The numerical analysis shows a tendency of broadened bead width and shallow penetration depth with the increase of rotating frequency. The simulation results are in good agreement with those obtained by the experiments under various welding conditions.

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