Go to the main menu
Skip to content
Go to bottom
REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Journal of Welding and Joining
Journal Basic Information
Journal DOI :
The Korean Welding and Joining Society
Editor in Chief :
Volume & Issues
Volume 21, Issue 7 - Dec 2003
Volume 21, Issue 6 - Oct 2003
Volume 21, Issue 5 - Sep 2003
Volume 21, Issue 4 - Aug 2003
Volume 21, Issue 3 - Jun 2003
Volume 21, Issue 2 - Apr 2003
Volume 21, Issue 1 - Feb 2003
Selecting the target year
Spraying Technology (II)
Journal of Welding and Joining, volume 21, issue 3, 2003, Pages 1~3
New Failure of Electronic Components
Journal of Welding and Joining, volume 21, issue 3, 2003, Pages 4~10
Failure Analysis of Electronic Components
Journal of Welding and Joining, volume 21, issue 3, 2003, Pages 11~16
Reliability Tests of Solder Joints
Journal of Welding and Joining, volume 21, issue 3, 2003, Pages 17~21
Reliability Tests of Solder Joints
Journal of Welding and Joining, volume 21, issue 3, 2003, Pages 22~29
Heat Distribution Characteristics of High Tensile Steel for Ship Structures in Laser Welding
Journal of Welding and Joining, volume 21, issue 3, 2003, Pages 30~34
This paper describes the heat distribution characteristics of ASTM A131DH36 high tensile steel for ship structures in 5㎾
laser welding. In general, high energy of laser beam concentrates on the small area of the weldment instantaneously; therefore, this heat transfer mechanism induces the rapid changes of temperature and mechanical characteristics in laser welds this mechanism. So temperature distribution analysis is important to understand mechanical characteristics of laser welds. Authors have conducted finite element simulation to analyze the heat distribution characteristics in laser welds. The result of simulation has been verified by comparing with the metallurgical experiment result. From the result of this study, we can accurately predict the heat distribution characteristics in laser welds by using numerical simulation.
Welding Residual Stresses Distribution Characteristics of High Tensile Steel for Ship Structures in Laser Welding
Journal of Welding and Joining, volume 21, issue 3, 2003, Pages 35~39
Laser welding has good characteristics such as high density energy, high speed and short heating time, as compared with conventional arc welding. The joint of laser welding also has good mechanical characteristics in general. However, relevant research is not sufficient to understand laser welding in the view point of mechanics until a recent date. In this paper, numerical simulation has been conducted to analyze distribution of welding residual stresses. Welding residual stresses of specimen have been measured by using sectioning method to compare the results between simulation and experiment.
A Study on Horizontal Fillet Welding by Using Rotating Arc (I) - Relation Between Welding Parameters and Weld Bead Shape
Journal of Welding and Joining, volume 21, issue 3, 2003, Pages 40~45
The high-speed rotating arc process forms a flat bead surface with decreased penetration depth because the molten droplets are deflected by centrifugal force. Therefore the rotating arc welding for horizontal fillet welding increases the leg length with the increase of rotation frequency and prevents the deflection of weld bead and overlap. In this study, the relationship between the welding parameters and the weld bead shape - leg length and undercut - are investigated experimentally. Consequently, the weld quality could be improved by rotating arc welding, and sound weld bead was achieved when applied to horizontal fillet welding with 4mm gap by avoiding the undercut which is inevitable for the conventional GMA welding methods.
A Study on Horizontal Fillet Welding by Using Rotating Arc (II) - Development of High-speed Welding Process -
Journal of Welding and Joining, volume 21, issue 3, 2003, Pages 46~50
The horizontal fillet joint is one of the most important weld joints in the shipbuilding industry. High-speed rotating arc welding, which can increase the leg length, is an effective way to improve the weld productivity and quality for the horizontal fillet welding. Based on the Taguchi method, the effects of welding parameters on bead characteristics - leg length, asymmetry, undercut, overlap - are investigated fur high-speed welding process. As a result, the adequate welding parameters are selected for the required leg length, symmetric bead and no undercut. Besides, considerably consistent leg length is observed for the horizontal fillet welding with gap variation up to 3mm.
A Study on the Metal Transfer and Spatter Generation in High Current
Journal of Welding and Joining, volume 21, issue 3, 2003, Pages 51~57
The metal transfer in
welding shows the transition of transfer mode from short-circuiting to repelled transfer will the increase of welding current. While the short-circuiting mode in
welding has been studied very extensively relating with droplet formation and spatter generation, the repelled transfer has little been understood. In this study, high current
welding has been performed with bead-on-plate welds along with the waveform analyzer and high speed camera. The image of high speed camera was synchronized with its waveform so that the moment of spatter generation could be realized during drop detachment. As a results of this study, it was found that welding arc changes its location either once or three times and thus single or double pulse signals were developed in the voltage waveform. Whenever the arc moved its location, new arc was developed in a explosive way and thus it caused spatter generation. Specially severe spattering took place when the waveform showed a double-peak pattern. As a consequence of these results, new waveform control techniques could be suggested for suppressing the spatter generation in the high-current
A Study on the Formation Mechanism of Discontinuities in
Laser Fusion Zone of Fe-Co-Ni Sintered Segment and Carbon Steel
Journal of Welding and Joining, volume 21, issue 3, 2003, Pages 58~67
In this study, the formation mechanism of discontinuities in the laser fusion zone of diamond saw blade was investigated.
laser weldings were conducted along the butt between Fe base sintered tip and carbon steel shank with sets of variable welding parameters. The effect of heat input on irregular humps, outer cavity, inner cavity and bond strengh was evaluated. The optimum heat input to have a proper humps was in the range of 10.4~
. With increasing heat input, both outer and inner cavities were reduced. The outer cavity was caused by insufficient refill of keyhole, while inner cavity was caused by trapping of bubble in molten metal. The bubble came from sintered tip and intensive vaporization at bottom tip of the keyhole. A gas formation and low melting point element vaporization were not occurred during welding. We could not find any relationship between bond strength and amount of discontinuities. Because the fracture were occurred in not only sintered tip but also carbon steel shank due to hardness distributions.
Thermal Elastic-Plastic Analysis of Strength Considering Temperature Rise due to Plastic Deformation by Dynamic Leading in Welded Joint
Journal of Welding and Joining, volume 21, issue 3, 2003, Pages 68~77
It is important to understand the characteristics of material strength and fracture under the dynamic loading like as earthquakes to assure the integrity of welded structures. The characteristics of dynamic strength and fracture in structural steels and their welded joints should be evaluated based on the effects of the strain rate and the service temperature. It is difficult to predict or measure temperature rise history with the corresponding stress-strain behavior. In particular, material behaviors beyond the uniform elongation can not be precisely evaluated, though the behavior at large strain region after the maximum loading point is much important for the evaluation of fracture. In this paper, the coupling phenomena of temperature and stress-strain fields under the dynamic loading was simulated by using the finite element method. The modified rate-temperature parameter was defined by accounting for the effect of temperature rise under the dynamic deformation, and it was applied to the fully-coupled analysis between heat conduction and thermal elastic-plastic behavior. Temperature rise and stress-strain behavior including complicated phenomena were studies after the maximum loading point in structural steels and their undermatched joints and compared with the measured values.
Transient Liquid Phase Bonding of Directionally Solidified Ni Base Superalloy, GTD-111(III) - The Effect of Homogenizing and Aging on the Microstructures and Mechanical Properties -
Journal of Welding and Joining, volume 21, issue 3, 2003, Pages 78~84
The changes of microstructure and hardness of TLP bonds of directionally solidified Ni base superalloy, GTD-111, with variation of homogenizing and aging treatment were investigated. The specimens were bonded at 1403K for 7.2ks using different insert metals such as MBF-50, MBF-80 and MBF-90 and they were homogenized at 1393K with various holding time. At center of bonded interlayer homogenized for hold time 30h, the contents of aluminum and titanium were approximately 90% and 95% of base metal, respectively. In this study, aging was performed at three different kinds : one step aging ; 1113K
16h, two step aging ; 1113K
10h ⇒ 1103K
10h, three step aging ; 1113K
10h ⇒ 1103K
8h ⇒ 922K
' volume fraction and hardness of joints were high in the sequence of one step, two step and three step aging, whereas
' volume fraction and hardness of joints obtained by three step aging treatment were higher than those of raw material. Tensile properties of joints bonded with MBF-80 and MBF-90, homogenized at 1393K for 30h and then three step aged became excellent than those of raw material, however, joint bonded with MBF-50 was poor.
Effect of Up-and-Down Torch Oscillation for Providing Uniform Heat Input along the Sidewall of Gap on Ultra Narrow Gap Welding
Journal of Welding and Joining, volume 21, issue 3, 2003, Pages 85~91
Narrow gap welding has many advantages over conventional V-grooved butt welding such as high productivity, small deformation and improved mechanical property of joints. With narrower groove gap, less arc heat input is expected will all the other advantages of narrow gap welding. The main defects of narrow gap welding include the lack of root fusion, convex bead surface and irregular surface, all of which have negative effects on the next welding pass. This paper suggests an up-and-down torch oscillation for ultra narrow gap welding with gap size of 5mm and investigates the proper welding conditions to fulfill the reliable and high welding quality. First, GMA welding model was suggested for ultra narrow gap welding system with Halmoy's model referenced for wire melting modeling. And the arc length in ultra narrow gap was defined. Secondly, based on the experimental results of up-and-down torch oscillation welding, phase shift of current and wire extension length were simulated for varying oscillation frequency to show that weld the bead shape in ultra narrow gap welding can be predicted. As the result, it was confirmed that reliable weld quality in ultra narrow gap welding can be achieved with up-and-down torch oscillation above 15Hz due to its ability to provide uniform heat input along the sidewall of gap.
Prediction of Thermal Fatigue Life on
BGA Solder Joint Using Sn-3.5Ag, Sn-3.5Ag-0.7Cu, and Sn-3.5Ag-3.0In-0.5Bi Solder Alloys
Journal of Welding and Joining, volume 21, issue 3, 2003, Pages 92~98
This paper describes the numerical prediction of the thermal fatigue life of a
BGA(Micro Ball Grid Array) solder joint. Finite element analysis(FEA) was employed to simulate thermal cycling loading for solder joint reliability. Strain values, along with the result of mechanical fatigue tests for solder alloys were then used to predict the solder joint fatigue life using the Coffin-Manson equation. The results show that Sn-3.5mass%Ag solder had the longest thermal fatigue life in low cycle fatigue. Also a practical correlation for the prediction of the thermal fatigue life was suggested by using the dimensionless variable
, which was possible to use several lead free solder alloys for prediction of thermal fatigue life. Furthermore, when the contact angle of the ball and chip has 50 degrees, solder joint has longest fatigue life.