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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 - Principle and Feature of Semi-Automatic
Journal of Welding and Joining, volume 19, issue 1, 2001, Pages 6~7
Reliability of Micro Joint and Its Application
Journal of Welding and Joining, volume 19, issue 1, 2001, Pages 8~14
Research Trends of Sn-Ag Based Pb-Free Solders
Journal of Welding and Joining, volume 19, issue 1, 2001, Pages 15~20
Analysis of Failure and Solution in BGA/CSP - Blow Hole -
Journal of Welding and Joining, volume 19, issue 1, 2001, Pages 21~23
Mounting Technology-Current State and Future Trends
Journal of Welding and Joining, volume 19, issue 1, 2001, Pages 24~26
A Study on the Welding Conditions of Weldability of Team Welding for Galvanized Steel Sheets of Automotive
Journal of Welding and Joining, volume 19, issue 1, 2001, Pages 27~32
This paper is studied about welding conditions and weldability of seam welding for galvanized steel sheet of automotive. The fuel tank of automobile is made by seam welding to be required of airtight or oiltight. This method have required a short time for welding, simplicity operation progress and little HAZ. Especially, it has more less residual stress and transformation than different welding progress. So, this study is for decreasing the leakage occurrence rate and to make standard operating condition table anyone can operate easily. Therefore, this study is analyzed the optimum conditions of seam welding for making the automobile with galvanized steel sheets by means of observing the microstructure and configuration back projection, RT, tensile-shear strengths test and SEM. Optimum conditions of seam welding obtained as follows, current 17.2-17.6kA speed 1.0m/min weld time 4:10:6 and current 16.5-17.4kA, speed 0.83m/min, weld time 4:10:4 at t1.0, and current, 18.5-18.9kA, speed 0.8m/min, weld time 4:10:4 and current 16.5-17.4kA, speed 0.68m/mi, weld time 4:10:2 at t1.6.
The Effect of Configuration and Surface Polishing in Tungsten Electrode Tip for Gas Tungsten Arc Welding on the Arc Characteristics
Journal of Welding and Joining, volume 19, issue 1, 2001, Pages 33~39
The welding quality by Gas Tungsten Arc Welding shows very high level, but the welding speed is lower than that of gas metal arc welding. Also, the welding quality by automatic GTAW is variable as the arc characteristics is changed by the consumption of electrode tip. The purpose of this study is to investigate the relation between the properties of tungsten electrode tip and the various arc characteristics at high current region. In this study, the high welding current 200A was applied to the repeated arc start test and long term arcing test using the
3.2 tungsten electrodes with cone angle 30
sharp tip, and 60
surface polished (S.P.) sharp tip. It was confirmed that the maximum arc pressure by the initial electrode condition was highest in 45
sharp tip, and the next in 60
sharp tip, the last was in 30
sharp tip and 60
S.P.. But, the maximum arc pressure after the repeated arc start test and long term arcing test was decreased considerably. But, the maximum arc pressure was highest also in 45
sharp tip after the tests, the next was in 30
sharp tip, and the last was in 60
sharp tip and 60
S.P.. The arc start characteristics was the most excellent in 60
S.P., By long term arcing test, the lanthania included in tungsten electrode was extinguished at tip surface preferentially, therefore the arc characteristics of electrode tip got worse.
Ultrasonic Test Criterion for the Explosively Welded Fe-Naval Brass Bonding Quality
Journal of Welding and Joining, volume 19, issue 1, 2001, Pages 40~48
An ultrasonic test method, as a nondestructive test is applied to ensure the clad interface quality assessment. According to the reference codes and standards, not only korea Industrial Standard(KS) but also American Society for Testing and Materials (ASTM) Standard, ultrasonic examination procedures use the pulse-echo, A-scan, back reflection signal drop method and/or side drilled reference hole used to establish the acceptance criteria of clad material test. But the variety of bonding materials and sizes makes it difficult to produce the reference blocks, or thus the criteria. In order to overcome these practical difficulties, new ultrasonic testing criterion is suggested. In this new method, the theoretical interface reflection signal amplitude level is calculated and suggested as an acceptance criteria with the back reflection signal set to 100% FSH(Full Screen Height) which is based on acoustic impedance mismatch at the clad interface for the explosive clad ultrasonic inspection. Applicability of suggested criterion, for the explosive clad Fe-Naval Brass with different bonding quality is confirmed to the pre-existed KS and ASTM specifications and verified by using SEM (Seanning Electron Microscope) micrograph. The results obtained by the suggested method is more conservative than the results according to the KS B 0234 and ASTM A 578 specifications The suggested method could be applicable to any other combination of explosive clad ultrasonic inspection.
The Effects of Geometrical Shape and Post Weld Treatment on Welding Residual Stress Distribution of Weldment in Multi-pass Welded Pipe
Journal of Welding and Joining, volume 19, issue 1, 2001, Pages 49~57
In this study, the residual stress fields of multi-pass welded were analyzed by FEA under various geometrical conditions. In order to estimate the effects of pipe geometries on residual stress distribution, welding processes of each model were performed under the same heat cycles. And then, the influence of cutting off the weld bead on the residual stress redistribution was also estimated. From the results, in the range of t/D=0.05, axial residual stresses on the outer surface of the welded pipe were linearly decreased with pipe diameter increase. On the other hand, hoop residual stresses were not influenced by them. And both axial and hoop residual stresses on the outer surface of the welded pipe were increased with pipe diameter increase. But, when t/D was smaller than 0.05, they were converged in the nearly same value. The maximum residual stresses were generated at around HAZ. It in therefore necessary to consider them in welding design, strength evaluation, and analysis of fracture characteristics.
Fatigue Life Evaluation of Spot Weldment Using DCPDM
Journal of Welding and Joining, volume 19, issue 1, 2001, Pages 58~64
The initiation and propagation lives of fatigue crack were studied for spot weldments composed of cold rolled steel plates(SPC
SPC) and galvanized steel plates(GA
GA) using DC potential drop method(DCPDM). Through the various test results, it was known that the fatigue crack initiation and propagation behaviors in all specimens could be definitely detected by DCPDM. The fatigue crack initiation life(
) detected by DCPDM in SPC
SPC and GA
GA spot weldments increased as the welding current and the nugget diameter(
) increased. The fatigue crack propagation life(
) declined as the difference of
and the fatigue fracture life(
) also increased according to the decrease of fatigue load,
P and the increase of nugget diameter. In the same spot weldments, the increase of nugget diameter came to increase fatigue crack propagation life owing to a decrease of stress concentration in front of nugget, especially the increasing extent for GA
GA spot weldment was very high. In the welding current 6kA,
GA spot weldment decreased more than that of SPC
SPC specimen due to zinc layer coated in steel plate and undersized nugget diameter. On the other hand, in 8kA and 10kA, the GA
GA spot weldment showed higher
in spite of lower
, than that of SPC
SPC specimen except 3,000N fatigue load.ue load. load.d.
A Study on the Post-Weld Heat Treatment Effect Affecting Corrosion Behavior and Mechanical Property of Welding Part of RE36 Steel for Marine Structure
Journal of Welding and Joining, volume 19, issue 1, 2001, Pages 65~74
A study on the corrosion behavior in case of As-welded and PWHT temperature 55
of welding part of RE36 steel for marine structure was investigated with parameters such as micro-Vickers hardness, corrosion potential measurement of weld metal(WM), base metal(BM) and heat affected zone(HAZ), both Al anode generating current and Al anode weight loss quantity under sacrificial anode cathodic protection conditions. And also we carried out slow strain rate test(SSRT) in order to research both limiting cathodic polarization potential for hydrogen embrittlement and optimum cathodic protection potential as well as mechanical properties by post-weld heat treatment(PWHT) effect. Hardness of HAZ was the highest among three parts(WM, BM and HAZ) and the highest galvanic corrosion susceptibility was HAZ. And the optimum cathodic polarization potential showing the best mechanical properties by SSRT method was from -770mV to -875mV(SCE). In analysis of SEM fractography, applied cathodic potential from -770mV to -875mV(SCE) it appeared dimple pattern with ductile fracture while it showed transgranular pattern (Q. C : quasicleavage) under -900mV(SCE). However it is suggested that limiting cathodic polarization potential indicating hydrogen embrittlement was under -900mV(SCE).
Metallurgical Study of Microconstituents in Transient Liquid Phase Bended Joints of Ni Base Superalloy
Journal of Welding and Joining, volume 19, issue 1, 2001, Pages 75~81
The metallurgical study of microconstituents in transient liquid phase bonded joints of Ni-base single crystal superalloys, CMSX-2 and CMSX-4 was investigated employing MBF-80 insert metal. TLP bonding of specimens was carried out at 1,373~1,523K for 0~19.6ks in vacuum. Three types of microconstituents ; needle-like constituent, dot-like constituent and abnormal shape constituent were formed in the bonded interlayer during TLP bonding operation. All these microconstituents were identified as boride. Microconstituents contain a large percentage of Cr in the early stage of bonding. As increasing the holding time, the amount of Cr was decreased and the amount of W, Co and Re were increased. From the analysis results of electron diffraction pattern by TEM, composition of elements in microconstituents were into MBlongrightarrowM
B type with the increased in holding time. It can be explained by the fact that the relative amount of boron in microconstituents was decreased when the holding time was increased.d.
Creep-Rupture and Fatigue Properties of Transient Liquid Phase Bonded Joints of Ni-Base Single Crystal Superalloy
Journal of Welding and Joining, volume 19, issue 1, 2001, Pages 82~87
The creep-rupture and low cycle fatigue properties of transient liquid phase bonded joints of Ni-base single crystal superalloy, CMSX-2 was investigated using MBF-80 insert metal. The (100) orientation of bonded specimen was aligned perpendicular to the joint interface. CMSX-2 was bonded at 1523K for 1.8ks in vacuum, optimum bonding condition. The creep rupture strength and rupture lives of the joints were the almost identical to ones of the base metal. SEM observation of the fracture surfaces of joints after creep rupture test revealed that the fracture surfaces classified three types of region, ductile fracture surface, cleavage fracture surface and interfacial fracture surface. The low cycle fatigue properties of the joints were also the same level as those of base metal. The elongation and reduction of area values of joints were comparable to those of base metal while fell down on creep rupture condition of high temperature.
A Study on the Micro-Focus X-Ray Inspection for Confirming the Soundness of End Closure Weld of DUPIC Fuel Elements
Journal of Welding and Joining, volume 19, issue 1, 2001, Pages 88~94
DUPIC (Direct use of spent PWR fuel in CANDU reactors) nuclear fuel is a CANDU fuel fabricated remotely from spent PWR fuel materials in a hot cell. The soundness of the end closure welds of nuclear fuel elements is an important factor for the safety and performance of nuclear fuel. To evaluate the soundness of the end closure welds of DUPIC fuel element, a precise X-ray inspection system is developed using a micro-focus X-ray generator with an image intensifier and a real time camera system. The fuel elements made of Zircaloy-4 and stainless steel by an Nd:YAG laser welding and a TIG welding aye inspected by the developed inspection system. The soundness of the welds of the fuel elements was confirmed by the X-ray inspection process, and the irradiation test of DUPIC fuel elements has been successfully completed at the HANARO research reactor.
A Study on the Erosion-Resistant Cermet Film Coating using the Detonation Spray Method
Journal of Welding and Joining, volume 19, issue 1, 2001, Pages 95~103
The properties of the detonation sprayed cermet coating are investigated through the mechanical, corrosion and erosion test. The test results are also compared with the properties of the substrate materials, STS 329J1, dual phase stainless steel and the plasma sprayed cermet coatings. The two kinds of carbide cermet power, WC+NiCr, Cr
+NiCr were used in this experiment. The experimental results showed that the anti-corrosive and anti-erosive properties of the detonation sprayed cermet coatings are superior to the plasma sprayed cermet coatings. The WC+NiCr cermet coating appears to be more effective than Cr
+NiCr cermet coating in abrasive erosion environment, whereas the Cr
+NiCr cermet coatings are more effective in cavitation erosion environment.
Analysis of Heat Flow and Deformation in Laser Welding of Small Gas Pressure vessel
Journal of Welding and Joining, volume 19, issue 1, 2001, Pages 104~111
This study presents an analysis method for heat flow and deformation of sheet metal laser welding. A heat source model for 2-dimensional heat flow analysis of laser welding process was suggested in this paper. To investigate the availability of the heat source model, the analysis results were compared and estimated with the results of previous researches. We could get a good agreement between the results of numerical analysis and experiments in the temperature distribution of weldment. Due to the characteristics of welding process, some kinds of deformations are usually generated in a welded structure. Generally, the degree of deformation is dependent on the welding sequence constraints as well as input power Therefore, in this paper we evaluate the deformation of gas pressure vessel according to the welding sequence and input power. In the analysis of weld deformation, 2-dimensional thermo-elasto-plastic analysis was performed for the gas pressure vessel by using a commercial FE program package.
A Study on the Effect of Fatigue and Crack Propagation Behavior in Spot Weld of High Strength Steel( I ) - Experimental Examination -
Journal of Welding and Joining, volume 19, issue 1, 2001, Pages 112~117
The factor affecting on the fatigue strength of spot welded specimen have been studied. To analyze and predict crack initiation position and propagation directions on the spot welded area are very important for strength design of the automobile body structure. In fact, there are a various of loads in running automobile but, it is impossible to replay like an actual conditions in the laboratory. So, in this study tensile-shear type and in-plane bending type specimens were used in fatigue test and includes an analysis of fatigue crack initiation position and propagation directions about earth specimens. The results obtained in the present study are summarized as follows: 1. In tensile-shear type fatigue test, the region of fatigue crack initiation position was affected by out-of-plane bending deformation due to bending angle. 2 In in-plane bending type fatigue test, the behavior of fatigue crack initiation position and propagation derections due to angle between upper plate and lower plate was dominated by magnitude of in-plane bending moment.