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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 15, Issue 6 - Dec 1997
Volume 15, Issue 5 - Oct 1997
Volume 15, Issue 4 - Aug 1997
Volume 15, Issue 3 - Jun 1997
Volume 15, Issue 2 - Apr 1997
Volume 15, Issue 1 - Feb 1997
Selecting the target year
The State-of-the-Art and a Prospect of Welding Information System
Journal of Welding and Joining, volume 15, issue 4, 1997, Pages 1~10
Development of management system for PQR
Journal of Welding and Joining, volume 15, issue 4, 1997, Pages 11~23
Computer Aided Spot Welding System in Automobile Industry
Journal of Welding and Joining, volume 15, issue 4, 1997, Pages 24~30
Development of Data Base System for Welding Information Management
Journal of Welding and Joining, volume 15, issue 4, 1997, Pages 31~35
Welding Expert System
Journal of Welding and Joining, volume 15, issue 4, 1997, Pages 36~41
A Study on Resistance Spot Welding of Dissimilar Sheet Metals(Aluminum Alloy - Steel Sheets)
Journal of Welding and Joining, volume 15, issue 4, 1997, Pages 42~62
Resistance spot welding has been widely used in the sheet metal joining processes because of its high productivity and convenience. Recently, automobile industries are trying to replace partly steel sheets with aluminum alloy sheets. Among currently produced aluminum alloys, Al alloy sheets of Al-Mg-Si(6000 series) are being tested. Especially, 6000 series are the most probable substitute in view of strength and weldability. In this paper, an attempt was made to apply resistance spot welding to joining of dissimilar sheet metals (KS6383+SCPZn or KS6383+SHCP). An effort was made to balance heating rate in the Al alloy with that in the steel sheets by increasing electrode tip diameter. Although resistance spot welding of Al alloy sheet and sheet metals does not produce desirable nugget, it proved to have reasonable strength if optimal weld condition is found by tensile-shear strength and fatigue life test. Since spot weld joints in automobile are always experiencing repeated load, spot welding methodology proposed in this paper is found to be not suitable to automobile body manufacturing.
A study on the estimate of the angular distortion for a fillet weldment
;;;Lee, S. H.;Cho, S. H.;
Journal of Welding and Joining, volume 15, issue 4, 1997, Pages 63~69
Welding distortion is more serious problem than any other problems caused by welding process, especially, in the heavy-industrial place. These welding distortions are caused by nonuniform heating and cooling of metal during and after welding operations. And these distortion quantities are must be known to worker in production line because distorions are important role in assembling part. Therefore an analytical model to explain and predict the welding distortion are needed. A numerical analysis of welding distortion which is inelastic behavior of weldment would require the three dimensional calculation. But computing time and memory would be very large, and the resulting cost might be unacceptable. Therefore we use a numerical technique for two dimensional analysis in the section normal to the weld direction of weldment under an assumption of quasi-stationary conditions. But the result of the calculation under two dimensional(plane strain) assumption was not satisfied as compared with experimental result. This paper proposed a technique for analysing the welding angular distortion by using a constraint boundary condition on the two dimensional finite element model. The simulation results revealed that the constraint boundary model could more reasonably describe the welding distortion than the plane strain model did.
A Study on the Optimization of Shape of Weld Joints
;;Bang, H. S.;Kim, J. M.;
Journal of Welding and Joining, volume 15, issue 4, 1997, Pages 70~77
Welding is one of the most important and popular joining techniques employed in structures. In spite of, weld designs depend on the rules and regulations. Moreover, the study to optimize a shape of welding joint not may be sufficient and systematic on the theoretical and experimental sides. Therefore, in this study, a computer program based on thermal elasto plastic theory is developed for optimizing(minimizing) shape of weld joints. By the results, study is made on the characteristics of the distributions of welding residual stresses and plastic strains, and their production mechanisms. Also, Various kinds of tests are carried out to find out mechanical characteristics due to shape of weld joints. As a result of this optimization(minimization) of weld joints, the productivity and the reliability will be improved.
A Study on the Cracking Behavior in the Welds of Ni-Cr-Fe and Ni-Fe-Cr-Mo Alloys Part I : Solidification Cracking in the Fusion Zone
Journal of Welding and Joining, volume 15, issue 4, 1997, Pages 78~89
This study has evaluated the weld metal solidification cracking behavior of several Ni base superalloys (Incoloy 825, Inconel 718 and Inconel 600). Austenitic stainless steels(304, 310S) were also included for comparison. In addition, a possible mechanism of solidification cracking in the fusion zone was suggested based on the extensive microstructural examinations with SEM, EDAX, TEM, SADP and AEM. The solidification cracking resistance of Ni base superalloys was found to be far inferior to that of austenitic stainless steels. The solidification cracking of Incoloy 825 and Inconel 718 was believel to be closely related with the Laves-austenite (Ti rich in 825 and Nb rich in 718) and MC-austenite eutectic phases formed along the grain boundaries during solidification. Cracking in Inconel 600 was always found along the grain boundaries which were enriched with Ti and P. Further, solidifidcation cracking resistance was dependent not only upon the type of love melting phases but also on the amount of the phases along the solidification grain boundaries.
Effects of Friction Pressure on Bonding Strength and a Characteristic of Fracture in Friction Welding of Cu to Cu-W Sintered Alloy
Journal of Welding and Joining, volume 15, issue 4, 1997, Pages 90~98
A copper-tungsten sintered alloy(Cu-W) has been friction welded to a tough pitch copper in order to investigate the effect of friction pressure on bonding strength and a charicteristic of fracture. The tensile strength of the friction welded joint was increased up to 90% of the Cu base metal under the condition of friction time 1.2 sec, friction pressure 4.5kgf/
and upset pressure 10kgf/
. From the results of fracture surface analysis, the increase of friction pressure could remarkably decrease the force and the time to be normally acted on weld interface. The W particles which were included in the plastic zone of Cu side could induce fracture adjacent to the weld interface because their existance in Cu induces a decrease in available section area and an increase in notch effect. Therefore, the tensile strength was decreased at high friction pressure (6kgf/
) because the destruction of W was increased by an increase in mechanical force and crack was formed at weld interface.
A Study on Thermal Analysis of Dual Beam Laser Welding of Thin Metal Sheet
Journal of Welding and Joining, volume 15, issue 4, 1997, Pages 99~108
Analytical model for the temperature distribution and the cooling rate of weld in dual beam laser welding is presented for investigating the possibility of controling the cooling rate. The model is based on the solutions to the problem of heat flow due to the distributed and line heat sources for preheating and welding respectively in plates with finite thickness. The effects of beam power, beam distribution parameter, interbeam distance, and welding speed on the resulting temperature distribution and cooling rate are presented. The cooling rates of dual beam laser weld at the weld centerline under the investigated conditions are reduced to as one third of those of welds which were produced by single beam laser. And it appeared that the cooling rate of dual beam laser weld is strongly dependent on the process parameters of preheating laser beam power and welding speed.
Cladding of Cu and Bronze/Al Alloy by
Journal of Welding and Joining, volume 15, issue 4, 1997, Pages 109~115
Laser cladding is a technique for modification of metal surface. In this laser cladding experiment a metal powder feeding system was developed for more efficient laser cladding. This system can reduce processing time and be used simpler than the conventional method. The feeding of metal powder has given a rise to the process for sequential buildup of bulk rapidly solidified materials in the form of fine powder stream to the laser cladding process. The parameters of laser cladding have been investigated using this experimental equipment. Bronze on aluminum alloy and copper on aluminum alloy were experimented by using defocused beam, powder feeding system, and gas shielding. Good cladding was achieved in the range of beam travel speed of 2.25m/min. In the case of copper/aluminum and bronze/aluminum substrate, the absorption of laser beam was too high to produce low diluted clad. In the case of copper/1050 aluminum, the optimal laser cladding condition was of laser power of 2.8kW, powder feed rate of 0.31g/s and beam travel speed of 2.25m/min. In the case of bronze/aluminum the optimal condition is of laser power of 2.5kW, powder feed rate of 0.31g/s, and beam travel speed of 2.36m/min.
A Study on electron beam veldability of 9%Ni steels (III) - Microstructures and mechanical properties of welded joints -
Journal of Welding and Joining, volume 15, issue 4, 1997, Pages 116~125
Electron beam weldability of 9%Ni steels has been investigated to apply EBW to the construction of LNG storage tank. While mechanical properties of welded joints were satisfied by ASTM specification, impact energy of weld metal was as low as 27 - 55J at
. As the result of Ni wires inserted at the joint to be welded, Ni content of weld metal was increased to about 10%, resulting on the improvement of impact toughness to 110 ~ 120J at
. This improvement of impact toughness in weld metal was due to the formation of tempered martensite and retained austenite. Above results indicate that, if Ni content of weld metal was increased about 10% by Ni wires addition, electron beam welded 9%Ni steels weld metal had sufficient impact energy necessary for a LNG storage tank.
Characteristics and oxidation behavior of the hybrid-HVOF sprayed
-7wt%(NiCr) coatings depending on
Journal of Welding and Joining, volume 15, issue 4, 1997, Pages 126~135
비에 따른 Hybrid HVOF 용사된
-7wt%(NiCr) 용사층의 특성 및 산화거동 This study was performed to investigate the influence of fuel/oxygen ratio (F/O=3.2, 3.0, 2.8) on the characteristics and the oxidation behavior of the hybrid-HVOF sprayed
-7wt%NiCr coatings. Decomposition and the oxidation of the
was occured during spraying. The degree of transformation from
was increased with decreasing the F/O ratio. The microstructural differences of the as sprayed coating with F/O ratio can not be distinguished, However, large pores were diminished and then the coatings became dense by heat treatment. Microhardness of the as-sprayed specimen which sprayed with F/O=3.0 condition was hightest (
=1140) and the hardness was increased to 1500 after heat treatment at
for 50hrs in air. It was supposed that hardness was increased due to the formation of
matrix and the densification of coating layer during heat treatment. Apparent activation energy for oxidation was varied from 21.2 kcal
to 23.8 kcal
with respect to the F/O ratio. The surface morphology was changed to porous and oxide chusters were grown after oxidation
for 50 hours by the aggressive evolution of gas phase (
). The oxide cluster was composed of Ni and Cr.
A Study on Liquid Phase Diffusion Bonding of STS304 using Cu-Mn-Si Insert alloy
Journal of Welding and Joining, volume 15, issue 4, 1997, Pages 136~142
In this study, the amorphous foil filler, thickness of 20 -
was made to develop Cu-7.5wt%Mn-7.5wt%Si insert alloy(melting point temperature : solidus line 1003K, liquidus line 1070K). Liquid phase diffusion bonding of 304 stainless steels (STS304), is carried out successfully by using developed Cu-7.5Mn-7.5Si insert alloy. Bonding conditions are taken from bonding pressure of 5MPa, bonding temperatures from 1073K to 1423K varied within 50K and brazing holding times of 0, 30, 60 and 240 minutes. As the results, the tensile strength in the liquid phase diffusion bonding is a little bit lower than that in the solid phase diffusion bonding. The authors find out that the liquid phase diffusion bonding needs lower bonding pressure than the others. Therefore, the liquid phase diffusion bonding had an excellent brazability in which the bonding process showed the typical mechanism of diffusion bonding. In corresponding, the new developed insert alloy of low melting pointed Cu-7.5Mn-7.5Si makes possible brazing between the STS304.
A Study on the Bending Strength of a Built-up Beam Fabricated by the
Arc Spot Welding Method
Journal of Welding and Joining, volume 15, issue 4, 1997, Pages 143~153
In this study, bending test was performed on the real-scale, built-up beam test model fabricated by the
arc spot welding to evaluate the applicability of the welding method to the production of the stiffened plate in car-carrying ship. The built-up beam models which were fixed at both ends in longitudinal direction or simply supported to the rigid foundation, depending on the restraint condition of the corresponding car decks considered, were subjected to simulated design vehicle loads or concentrated point loads. During the test, the central deflection and the longitudinal bending stresses were measured from several points on the longitudinal flange face to predict the section properties of the built-up beams. The longitudinal bending stress on each spot weld were also measured to calculate the average horizontal shear force subjected to spot welds. Test results revealed that the shear strength of spot welds with their current weld nugget size and welding pitch was adequate enough to withstand the horizontal shear forces under the design vehicle loads. Although the built-up beam fabricated by the arc spot welding was a discontinuous beam, its mechanical behavior was well explained by the continuous beam theory using the effective breadth of plate. Based on test results, the criterion for the size of spot weld of which the average shear stress might meet the allowable stress requirement of AWS Code could be established.
Abrasive wear characteristics of high Cr cast iron hardfacing
Journal of Welding and Joining, volume 15, issue 4, 1997, Pages 154~165
Abrasive wear characteristics of high Cr white cast iron-based hardfacing were investigated using the rubber wheel abrasion wear test method according with the ASTM G65-85. Mild steel was also tested for comparison with high Cr cast iron hardfacing. Wear experiments, where the applied force, wheel revolution rate and abrasive powder feed rate were selected as test valuables, were planned and analyzed by response surface method to evaluate wear statistically and quantitatively. Weight loss of high Cr cast iron hardfacing was mostly affected by the applied force and wheel revolution rate, and little by the powder feed rate. Weight loss of mild steel was greatly affected by the wheel revolution rate and powder feed rate, and slowly and steadily increased with the applied force. Abrasive wear mechanism of high Cr cast iron and mild steel was discussed in the light of the wear test results.
Investigations on electron beam weldability of AlZnMgCu0.5 alloys
Journal of Welding and Joining, volume 15, issue 4, 1997, Pages 166~177
The high strength AlZnMgCu0.5 alloy is a light metal with good age hardenability, and has a high tensile and yielding strength. Therefore, it can be used for structures requiring high speciple strength. Even though high strength AlZnMgCu alloy has good mechanical properties, it has a lot of problems in TIG and MIG welding processes. Since lots of high heat absorption is introduced into the weldment during TIG and MIG processes, the microstructural variation and hot cracks take place in heat affected zone. Therefore, the mechanical properties of high strength AlZnMgCu0.5 alloy can be degraded in weldment and heat affected zone. Welding process utilizing high density heat source such as electron beam should be developed to reduce pore and hot cracking, whichare usually accompanied by MIG and TIG welding processes. In this work, electron beam welding process were used with or without AlMg4.5Mn as filler material to avoid the degradation of mechanical properties. Mechanical and metallurgical characteristics were also studied in electron beam weldment and heat affected zone. Moreover hot cracking mechanism was also investigated.
Evaluation of J-R Curve for Aluminum 5083 Alloy Weldment by Load Ratio Analysis
Journal of Welding and Joining, volume 15, issue 4, 1997, Pages 178~186
The purpose of this study is to evaluate the J-R curve characteristics for the 5083 aluminum alloy weldment by the load ratio analysis. The results of the load ratio analysis are compared with those of the J-R curve which are obtained by the ASTM unloading compliance method. The crack length calculated by the load ratio analysis is agrees well with the measured final crack length. The slope of the exponential J-R curve estimated by the load ratio analysis is slightly smaller than that by the ASTM unloading compliance method. The exponential correlation of the J-R curve for the 5083 aluminum alloy base metal by the load ratio analysis is J = 93.88
. That for the weld metal and HAZ is J = 69.87
and J = 70.59
respectively. The J-R curve obtained by the ASTM unloading compliance method is overpredicted and should be offsetted due to the initial negative crack. On the other hand, the load ratio analysis method can evaluate the J-R curve by only load displacement curve without particular crack measurement equipment.
Effect of Residual Stress on Fatigue Crack Growth Rate at Welds of SUS-304 Steel
Journal of Welding and Joining, volume 15, issue 4, 1997, Pages 187~193
In the weldmentsm the crack propagation rate is changed due to the residual stress. The crack propagation rate is high in the region with the residual stress. However it shows rhw same behavior with the base metal in the region that does not include the residual stress. The fatigue crack growth rate for the material with residual stresses can be predicted more precisely by using the effective stress ratio. The difference between experimental results and prediction results in the initial stage seems to be due to the redistribution of residual stresses and microstructural change.