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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 31, Issue 6 - Dec 2013
Volume 31, Issue 5 - Oct 2013
Volume 31, Issue 4 - Aug 2013
Volume 31, Issue 3 - Jun 2013
Volume 31, Issue 2 - Apr 2013
Volume 31, Issue 1 - Feb 2013
Selecting the target year
Specification of Governing Factors for High Accurate Prediction of Welding Distortion
Lee, Jae-Yik ; Chang, Kyong-Ho ; Kim, You-Chul ;
Journal of Welding and Joining, volume 31, issue 5, 2013, Pages 1~6
DOI : 10.5781/KWJS.2013.31.5.1
In carrying out the elastic-plastic analysis, four conditions (equilibrium equation, constitutive equation, condition of compatibility and yield condition) should be satisfied. In welding, the temperature largely changed from a melting temperature to a room temperature. So, yield stress of materials largely changed, too. In particular, yield stress becomes about zero over
. The analysis should be carried out under the condition that equivalent stress generated in temperature increment
did not exceed yield stress of materials at high temperature over
. It should be sufficiently recognized that the obtained results were not reliable if this condition was not satisfied.
Verification of Validity of Governing Factors in High Accurate Prediction of Welding Distortion
Lee, Jae-Yik ; Chang, Kyong-Ho ; Kim, You-Chul ;
Journal of Welding and Joining, volume 31, issue 5, 2013, Pages 7~14
DOI : 10.5781/KWJS.2013.31.5.7
The legitimacy of dominating factor in the high accuracy prediction of welding distortion was investigated for butt welding and fillet welding. When out-of-plane distortion was measured by the experiment objecting to butt welding, if tack welding was easily performed, the position of a neutral axis was variously changed by the irregularity. Then, there have been a case that out-of-plane distortion was generated in the unexpected direction. This case should be especially noted. New model for the experiment was proposed so as to solve this problem. As it was elucidated by the case of fillet welding, it was verified that the analysis should be carried out with satisfying the yield condition (especially at high temperature above 700 degree Celsius) and with closely simulating the penetration shape (heat input in weld metal) in order to solve the proposition that is the high accuracy prediction of welding distortion. It was confirmed that residual stress is highly predicted because welding distortion is highly predicted, too.
Prediction of Welding Imperfection with Idealization of Welding and Their Accuracy
Lee, Jae-Yik ; Chang, Kyong-Ho ; Kim, You-Chul ;
Journal of Welding and Joining, volume 31, issue 5, 2013, Pages 15~19
DOI : 10.5781/KWJS.2013.31.5.15
In order to reduce a grand compute time in prediction of welding distortion and residual stress by 3D thermal elastic plastic analysis, idealization of welding that is methods to heat input simultaneously in all weld metal on the same welding direction is carried out on two weld joints(butt welding and fillet welding). Then, the accuracy of acquired results is investigated through the comparison of the high accuracy prediction results. The thermal conduction analysis results by idealization of welding, the temperature is raised accompany with beginning of heat input because all of weld metal is heated input at the same time. On the other side, the temperature witch predicted with high accuracy is raised at the moment heating source passes the measuring points. So, there is difference of time between idealization of welding and considering of moving heat source faithfully. However, temperature history by idealization of welding is well simulated a high accuracy prediction results.
Heat Treatment Effect on Pitting Corrosion of Super Duplex Stainless Steel UNS S32750 FCA Welds
Jang, Bok-Su ; Moon, In-June ; Kim, Se-Cheol ; Koh, Jin-Hyun ;
Journal of Welding and Joining, volume 31, issue 5, 2013, Pages 20~25
DOI : 10.5781/KWJS.2013.31.5.20
This study was carried out to investigate the influence of a sigma phase precipitation on the pitting corrosion resistance and microstructural change of super duplex stainless steels(UNS S32750). The welds made by FCAW (Flux Cored Arc Welding) were heat treated (
) and quenched. Based on the microstructural examination, it was found that the
phase was formed in base metals and welds heat treated at
while there were little
phases formed in base metals and weld metal experienced the relatively fast cooling from
. On the other hand, the most weight loss due to pitting corrosion occurred in base and weld metals heat treated at
. It was confirmed that the pitting corrosion occurred in the phase boundaries of ferrite/sigma and austenite/sigma. The pitting corrosion resistance decreased owing to an increase in Cr, Mo depleted areas adjacent to the intermetallic phases such as
phases. The hardness was greatly increased due to the precipitation
A Study on Mechanical Properties Changes to Improve the Confidence of Remaining Life Evaluation for the Weldment of Power Plant Boiler Tube
Oh, Byungjin ; Jang, Joong Soon ;
Journal of Welding and Joining, volume 31, issue 5, 2013, Pages 26~34
DOI : 10.5781/KWJS.2013.31.5.26
Boiler equipment in power plant is always being operated in harsh conditions and severely exposed to the extreme environment of high temperature. Therefore periodically the state of devices should be checked, diagnosed, and analyzed to ensure the reliability of the equipment. Traditionally, such a diagnosis is based one or two physical properties of the sample taken from the equipment like hardness, microstructure, etc.. However, to enhance the confidence of the diagnosis, it is necessary to synthesize those properties together. This paper is to propose such a synthetic procedure for T23 which was developed to be used in
condition. Creep test and accelerated degradation test were performed simultaneously, and the physical properties such as microstructure, tensile strength, yield strength, hardness, and indentation properties were measured. This paper proposes a method of determining the remaining life by quantitative comparison. It will provide the basis of evaluating life assessment more objective and reliable.
Using Neural Network Algorithm for Bead Visualization
Koo, Chang-Dae ; Yang, Hyeong-Seok ; Kim, Jung-Yeong ; Shin, Sang-Ho ;
Journal of Welding and Joining, volume 31, issue 5, 2013, Pages 35~40
DOI : 10.5781/KWJS.2013.31.5.35
In this paper, we propose the Tangible Virtual Reality Representation Method to using haptic device and feature to morphology of created bead from Flux Cored Arc Welding. The virtual reality was started to rising for reduce to consumable materials and welding training risk. And, we will expected maximize virtual reality from virtual welding training. In this paper proposed method is get the database to changing the input factor such as work angle, travelling angle, speed, CTWD. And, it is visualization to bead from extract to optimal morphological feature information to using the Neural Network algorithm. The database was building without error to extract data from automatic robot welder. Also, the Neural Network algorithm was set a dataset of the highest accuracy from verification process in many times. The bead was created in virtual reality from extract to morphological feature information. We were implementation to final shape of bead and overlapped in process by time to using bead generation algorithm and calibration algorithm for generate to same bead shape to real database in process of generating bead. The best advantage of virtual welding training, it can be get the many data to training evaluation. In this paper, we were representation bead to similar shape from generated bead to Flux Cored Arc Welding. Therefore, we were reduce the gap to virtual welding training and real welding training. In addition, we were confirmed be able to maximize the performance of education from more effective evaluation system.
Measurement of Weld Material Properties of Alloy 617 Using an Instrumented Indentation Technique
Song, Kee-Nam ; Hong, Sung-Deok ; Ro, Dong-Seong ; Lee, Joo-Ha ; Hong, Jung-Hwa ;
Journal of Welding and Joining, volume 31, issue 5, 2013, Pages 41~46
DOI : 10.5781/KWJS.2013.31.5.41
Different microstructures in the weld zone of a metal structure such as a fusion zone or heat affected zone are formed as compared to the parent material. Thus, the mechanical properties in the weld zone are different from those in the parent material. As the basic data for reliably understanding the structural characteristics of a welded PCHE specimen to be made of Alloy 617, the mechanical properties in the weld zone and parent material for a Alloy 617 plate are measured using an instrumented indentation technique in this study.
Evaluation of Corrosion Resistance and Weldability for the Butt Welding Zone of Hot Rolled Clad Steel Plates
Park, Jae-Won ; Lee, Chul-Ku ;
Journal of Welding and Joining, volume 31, issue 5, 2013, Pages 47~53
DOI : 10.5781/KWJS.2013.31.5.47
We have investigated the traits of clad metals in hot-rolled clad steel plates, including the sensitization and mechanical properties of STS 316 steel plate and carbon steel (A516), under various specific circumstances regarding post heat treatment, multilayered welds, and thick or repeated welds for repair. For evaluations, sectioned weldments and external surfaces were investigated to reveal the degree of sensitization by micro vickers hardness, tensile, and etching tests the results were compared with those of EPR tests. The clad steel plates were butt-welded using FCAW and SAW with the time of heat treatment as the variable, a that was conducted at
, for 80, 160, 320, 640, and 1280 min. Then, the change in corrosion resistance was evaluated in these specimens. With carbon steel (A516), as the heat treatment time increased, the annealing effect caused the tensile strength to decrease. The micro-hardness gradually increased and decreased after 640 min. The elongation and contraction of the area also increased gradually. The oxalic acid etch test and EPR test on STS316 and the clad metal showed STEP structure and no sensitization. From the test results on multi-layered and repair welds, it could be concluded that there is no effect on the corrosion resistance of clad metals. The purpose of this study was to suggest some considerations for developing on-site techniques to evaluate the sensitization of stainless steels.
Joint Property of Sn-Cu-Cr(Ca) Middle Temperature Solder for Automotive Electronic Module
Bang, Junghwan ; Yu, Dong-Yurl ; Ko, Yong-Ho ; Kim, Jeonghan ; Lee, Chang-Woo ;
Journal of Welding and Joining, volume 31, issue 5, 2013, Pages 54~58
DOI : 10.5781/KWJS.2013.31.5.54
Joint properties of vehicle ECU (Electric Control Unit) module which was manufactured by using Sn-Cu-Cr-Ca alloy were investigated. A new solder which has a middle melting temperature about
was fabricated as the type of 300um solder ball and paste type. The prototype modules were made by reflow process and measured spreadability, wettability shear strength and estimated interface reaction. The spreadability of the alloy was about 84% from the measurement of contact angle of the solder ball and the wetting force was measured 2mN. The average shear strength of the module which was manufactured by using the solder paste, was 1.9
. Also, the thickness of IMC(intermetallic compound) was evaluated with various aging temperature and time in order to understand Cr effect on Sn-0.7Cu solder.
IMC was formed between Cu pad and the solder alloy and the average thickness of the
IMC was measured about 4um and it was about 50% of thickness of
IMC in Sn-0.7Cu. It is expected to have a positive effect on reliability of the solder joint.
Failure Mechanism of Bendable Embedded Electronic Module Under Various Environment Conditions
Jo, Yun-Seong ; Kim, A Young ; Hong, Won Sik ;
Journal of Welding and Joining, volume 31, issue 5, 2013, Pages 59~63
DOI : 10.5781/KWJS.2013.31.5.59
A bendable electronic module has been developed for a mobile application by using a low-cost roll-to-roll manufacturing process. In flexible embedded electronic module, a thin silicon chip was embedded in a polymer-based encapsulating adhesive between flexible copper clad polyimide layers. To confirm reliability and durability of prototype bendable module, the following tests were conducted: Moisture sensitivity level, thermal shock test, high temperature & high humidity storage test, and pressure cooker tester. Those experiments to induce failure of the module due to temperature variations and moisture are the experiment to verify the reliability. Failure criterion was 20% increase in bump resistance from the initial value. The mechanism of the increase of the bump resistance was analyzed by using non-destructive X-ray analysis and scanning acoustic microscopy. During the pressure cooker test (PCT), delamination occurred at the various interfaces of the bendable embedded modules. To investigate the failure mechanism, moisture diffusion analysis was conducted to the pressure cooker`s test. The hygroscopic characteristics of the encapsulating polymeric materials were experimentally determined. Analysis results have shown moisture saturation process of flexible module under high temperature/high humidity and high atmosphere conditions. Based on these results, stress factor and failure mechanism/mode of bendable embedded electronic module were obtained.
Weldability of SUS304 and Ti Dissimilar Welds with Various Welding Speed using Single Mode Fiber Laser
Lee, Su-Jin ; Katayama, Seiji ; Kim, Jong-Do ;
Journal of Welding and Joining, volume 31, issue 5, 2013, Pages 64~70
DOI : 10.5781/KWJS.2013.31.5.64
The joining of Ti and SUS304 dissimilar metals is one of the effective measures to save rare metal. But Ti and SUS304 have differences in materials properties, and Ti and Fe intermetallic compounds such as TiFe and
are easily formed in weld fusion zone between Ti and SUS304. Nevertheless, in this study, full penetration lap dissimilar welding of Ti and SUS304 using single-mode fiber laser with ultra-high welding speed was tried, and it was found out that ultra-high welding speed could control the generation of intermetallic compound. To recognize the formation of intermetallic phase in the weld fusion zone and the compound zone of interface weld area were observed and analyzed using energy dispersive X-ray spectroscopy (EDX). And it was confirmed that the ultra-high welding speed could reduce amount of intermetallic compounds, but the intermetallic compounds were existed in the weld fusion zone under the all conditions.
The Effect of Zirconate Addition on the Joint Properties of Epoxy Adhesive for Car Body Assembly
Jeung, Eun-Taek ; Lee, Hye-Rim ; Lee, So-Jeong ; Lim, Chang-Young ; Seo, Jong-Dock ; Kim, Mok-Soon ; Kim, Jun-Ki ;
Journal of Welding and Joining, volume 31, issue 5, 2013, Pages 71~76
DOI : 10.5781/KWJS.2013.31.5.71
The effect of zirconate having - NH functional group on the T-peel and lap shear strength of
containing structural epoxy adhesive for car body assembly was investigated. Curing behavior of epoxy adhesive samples were investigated by differential scanning calorimeter (DSC) techniques. The addition of zirconate up to 7.5 phr did not affect the curing mechanism of epoxy adhesive. While the small amount of zirconate addition less than 1.1 phr increased the cross-linking density, the excess addition of zirconate resulted in the increase of uncross-linked impurity. From the increase of T-peel and lap shear strength and the change of fracture mode from the adhesive failure to the mixed one, it was considered that the small addition of zirconate was effective in improving the adhesion strength of epoxy adhesive to the adherend and inorganic filler surfaces. The formation of uncross-linked impurity with the excess addition of zirconate was considered to decrease the joint strength by decreasing the cohesive strength of the cured epoxy.
Thermal Stability of the Mechanical and Thermal Conductive Properties on Cu-STS-Cu Clad Metal for LED Package Lead Frame
Kim, Young-Sung ; Kim, Il-Gwon ;
Journal of Welding and Joining, volume 31, issue 5, 2013, Pages 77~81
DOI : 10.5781/KWJS.2013.31.5.77
We have investigated thermal stability of the mechanical and thermal conductive properties of Cu/STS/Cu 3 layered clad metal lead frame material for a LED device package at different temperatures ranging from RT to
. The fabricated Cu/STS/Cu clad metal has a good thermal stability for the mechanical tensile strength and thermal conductivity of the over 50
, respectively. This clad metal lead frame material at a high temperature of
shows a reinforced mechanical tensile strength by 1.5 times to conventional pure copper lead frame materials and also a comparable thermal conductivity to typical copper alloy lead frame materials.