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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 19, Issue 6 - Dec 2001
Volume 19, Issue 5 - Oct 2001
Volume 19, Issue 4 - Aug 2001
Volume 19, Issue 3 - Jun 2001
Volume 19, Issue 2 - Apr 2001
Volume 19, Issue 1 - Feb 2001
Selecting the target year
Fundamentals of Fusion Welding(IV) - Characteristics of Flux for Submerged Arc Welding
Journal of Welding and Joining, volume 19, issue 4, 2001, Pages 363~365
Development of Power Feedback Nd:YAG Laser with Waveform Control Function
Journal of Welding and Joining, volume 19, issue 4, 2001, Pages 366~370
Nd:YAG Laser Welding for Side Panel
Journal of Welding and Joining, volume 19, issue 4, 2001, Pages 371~374
Surface Hardening Technology of the Metal by High Temperature Pulsed Plasma Flux
Journal of Welding and Joining, volume 19, issue 4, 2001, Pages 375~378
The new development of the surface hardening technology has been attracted to machine designer and materials scientist in the view point of improvement in the lifetime and performance of the machine. The heat-treatment process has been a well-known technology to make harden the metal surface despite of its inefficiency in productivity and its inherent environmental pollution problem. Therefore, the plasma technology has been applied to the conventional process to improve the above issues and become successful in diminishing the ecological harmfulness. However, the drastic short processing time has been sought to increase the productivity by means of new plasma technology so-called, high temperature pulsed plasma flux (HTPPF). The basic principle and features of this HTPPF will be introduced and the present status of this technology will be described in this paper.
The Quality Evaluation on Resistance Spot Welding of 2024 Aluminum Alloy and Zinc Coated Steel
Journal of Welding and Joining, volume 19, issue 4, 2001, Pages 379~383
Resistance spot welding has been widely used in the sheet metal joining processes because of low cost, high productivity and convenience. Recently, automobile and aerospace industries are trying to replace partly steel sheets with aluminum alloy sheets. But in the case of dissimilar materials, to apply resistance spot welding has been known to be very difficult owing to the effect of melting temperature. On this study, an effort was made to apply spot welding of dissimilar sheet metals, 2024 aluminum alloy and zinc coated steel sheet, evaluate the spot weld quality with tensile-shear strength test and nondestructive evaluation technique, C-scan image methodology. In this study results, as the current below 11 kA, melting of materials is not achieved well. Also as the current exceeds to 13.5 kA, the more spatters happen at welded zone and tensile-shear strength lowered. So, the feasibility of C-scan image technique proposed in the study is found to be suitable evaluation method for resistance spot weldability.
A Study on the Temperature Distribution and Deformation of Case in Shrinkage Fit Process(I) - Temperature Monitoring and Heat Transfer Analysis Model -
Journal of Welding and Joining, volume 19, issue 4, 2001, Pages 384~390
There have been many problems due to deformation in industry field. Especially, it is severe in parts with small size and thin thickness and in products that must have excellent airtightness and anti-noise. The countermeasures for this deformation in field have mainly been dependent on the rule of trial and error by operator's experience because of productivities. Systematic study about this product with deformation is also insufficient that deformation is complex problem with shape, size, material of product, joining method and conditions, etc.. It is efficient to apply CAE technique without influence on productivity to this problem. There is, however much difference between the result analyzed by CAE and appearances in working field because of the insufficiency of communication between simulator and worker and of sensing data for boundary condition in analysis. In this study, to solve this deformation problem, we intend to make a simulation model that is adapted from working conditions by tuning and feedback between sensing data and simulation results. This paper include temperature monitoring and make a heat transfer model using sensing data in product as previous step for deformation analysis. The heat transfer analysis of shrinkage fit process is considerably difficult due to contact heat transfer between case and core. To solve this contact problem, gap element is used in present study.
A Study on an Electro-Magnetic System far Arc Rotating in MIAB Welding
Journal of Welding and Joining, volume 19, issue 4, 2001, Pages 391~398
MIAB welding method uses a rotating arc as its heat source and is known to be efficient in pipe butt welding. The arc is rotated around the weld line by the electro-magnetic force resulting from the interaction of arc current and magnetic field. This paper is concerned with the experiment of initial stage for process control, monitoring for weld quality, and the design of coil system which is efficient of flux generation and concentration. A coil system for the generation of magnetic flux was designed and constructed. Magnetic flux density and arc rotating behavior are important factors in MIAB welding, so the relations between these factors and process parameters were investigated. Various experiments were performed for the steel pipes(48.1mm O.D and 2.0mm thickness). The magnetic flux density is increased by increasing exciting current and decreasing gap size. The maximum of arc rotating frequency is affected by exciting current and gap size. However, the variations of arc rotating frequency during welding and then the melting process are mainly influenced by welding current. Thus, it is considered that the results of this study can be used as important data on the monitoring for weld quality and the design of efficient coil system.
Analysis of Metal Transfer using Dynamic Force Balance Model in GMAW
Journal of Welding and Joining, volume 19, issue 4, 2001, Pages 399~405
A dynamic force balance model is proposed in this work as an extension of the previous static force balance model to predict metal transfer in arc welding. Dynamics of a pendant drop is modeled as the second order system, which consists of the mass, spring and damper. The spring constant of a spherical drop at equilibrium is derived in the closed-form equation, and the inertia force caused by drop vibration is included in the drop detaching condition. While the inertia force is small in the low current range, it becomes larger than the gravitational force with current increase. The inertia force reaches half of the electromagnetic force at transition current, and has considerable effects on drop detachment. The proposed dynamic force balance model predicts the detaching drop size more accurately than the static force balance model.
Thermal Fatigue Life Prediction of
Solder Joint Using Sn-37mass%Pb Solder and Sn-3.5mass%Ag Lead-free Solder
Journal of Welding and Joining, volume 19, issue 4, 2001, Pages 406~412
This study is focussed on the numerical prediction of the thermal fatigue life of a
(Micro Ball Grid Array) solder joint. Numerical method is used to perform three-dimensional finite element analysis for Sn-37mass%Pb. Sn-3.5mass%Ag solder alloys during the given thermal cycling. 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. In this study, a practical correlation for the prediction of the thermal fatigue life is suggested by using the dimensionless variable
. As a result. it could be found that Sn-3.5mass%Ag has longer fatigue life than Sn-37mass%Pb in low cycle fatigue. In addition. the result with
a good agreement with the FEA results.
A Study of Heat Flow and Residual Stress Analysis in Pipe-plate Gas Metal Arc Brazing
Journal of Welding and Joining, volume 19, issue 4, 2001, Pages 413~422
In this study. two-dimensional heat flow and residual stress in arc brazing to join the pipe and plate structure were analyzed by using a commercialized FEM package. Advantages offered by arc brazing are that strong joints can be produced with lower heat input than that of previous gas metal arc welding and narrower heat affected zone can usually be obtained than that in the case of torch brazing. To investigate the effects of process variables and minimize the thermal effects on the structure, this study presents a method for analyzing the heat flow and residual stress in arc brazing process according to variables such as traveling speed, torch angle and position. The simulation results were compared with the experimental ones to verify the numerical analysis method. The experiments include the measurement of HAZ size from the section of joints and residual stresses by using strain gages named 'section method'. A comparatively good agreement between the results of numerical analysis and experimental ones could be obtained in both of the temperature distribution and residual stress of the brazed structure. Using the proposed numerical analysis method, the process parameters were evaluated to get proper arc brazing conditions.
Bonding Phenomena during Transient Liquid Phase Bonding of CMSX-4, High Performance Single Crystal Superalloy
Journal of Welding and Joining, volume 19, issue 4, 2001, Pages 423~428
The bonding phenomena of Ni base single crystal superalloy. CMSX-4 during transient liquid phase(TLP) bonding was investigated using MBF-80 insert metal. Bonding of CMSX-4 was carried out at 1,373∼1,548K for 0∼19.6ks in vacuum. The (001) orientation of each test specimen was aligned perpendicular to the bonding interface. The dissolution width of base metal was increased when the bonding temperature and holding time were increased. The eutectic width diminished linearly with the square root of holding time during isothermal solidification process. Borides were formed in the bonded layer during TLP bonding operation. The solid phase grew epitaxially into the liquid phase from substrates and single crystallization could be readily achieved during the isothermal solidification.
Microstructural Features of Al Alloy 7N01 Welded by
Laser - Microsturctural Features of Full Penetration Joints -
Journal of Welding and Joining, volume 19, issue 4, 2001, Pages 429~436
The effect of welding condition on the microstructures of the weld metal in A7N01 welded by
laser was investigated. The number of ripples was increased with decreasing power and increasing welding speed. In the bead without ripple lines, the subgrain microstructures distribution from the fusion line toward the center of the bead were in the order of cellular, dendritic and equiaxed dendrite. However, in the bead with ripple lines, cellular and dendritic were formed between the fusion boundary and the ripple line. Inaddition, those structures were also observed between the ripple line. Equiaxed dendrites were formed only at the center line region. Cellular and dendritics formed near the ripple line were larger than those formed near the fusion boundary. The cooling rates estimated by the dendrite arm spacing were in the range of 200 to 1150oC/s. Cooling rate was increased with decreasing the power and increasing the welding speed. Mg and Zn segregated at the boundaries of cellulars and dendritics, Mg was segregated more than Zn. The segregation of Mg and Zn decreased with increasing cooling rate. Hardness of the weld metal was lower than that of the base metal in all welding conditions and increased as the cooling rate increased.