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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 33, Issue 6 - Dec 2015
Volume 33, Issue 5 - Oct 2015
Volume 33, Issue 4 - Aug 2015
Volume 33, Issue 3 - Jun 2015
Volume 33, Issue 2 - Apr 2015
Volume 33, Issue 1 - Feb 2015
Selecting the target year
High efficient welding technology of the offshore wind power plants
Kim, Youngsik ; Kil, Sangcheol ;
Journal of Welding and Joining, volume 33, issue 3, 2015, Pages 4~11
DOI : 10.5781/JWJ.2015.33.3.4
The offshore wind power plants are watched as a new market to accomplish the needed energy, bringing technical and economical challenges. Advanced countries in the field of wind industry are now appling the 600 MPa, 150~200 mm thick high strength steel to offshore wind power plants. Moreover, the high efficient welding methods which is weldable ultra tick high strength steel with 1 pass welding are developed and applied in manufacturing the offshore wind tower. This article deals with the present world wide status of offshore power plants and the tendency of the development of high efficient welding technology for constructing the offshore wind tower. This article intends to offer the materials for development and raising of the domestic offshore wind power technology.
Mechanical fastening and joining technologies to using multi mixed materials of car body
Kim, Yong ; Park, Ki-Young ; Kwak, Sung-Bok ;
Journal of Welding and Joining, volume 33, issue 3, 2015, Pages 12~18
DOI : 10.5781/JWJ.2015.33.3.12
The ultimate goal of developing body is revealed the "lightweight" at latest EuroCarBody conference 2012 and the most core technology is joining process to make lightweight car body design. Accordingly, in this study, the car body assembly line for the assembly process applies to any introduction, particularly in the assembly of aluminum alloy and composite materials applied by the process for the introductory approached. Process were largely classified by welding (laser, arc, resistance, and friction stir welding), bonding (epoxy bonding) and mechanical fastening (FDS, SPR, Bolting and clinching). Applications for each process issues in the case and the applicable award was presented, based on the absolute strength of the test specimens and joining characteristics for comparative analysis were summarized. Finally, through this paper, we would tried to establish the characteristics of the joint for lightweight structure.
A study of joint properties of Sn-Cu-(X)Al(Si) middle-temperature solder for automotive electronics modules
Yu, Dong-Yurl ; Ko, Yong-Ho ; Bang, Junghwan ; Lee, Chang-Woo ;
Journal of Welding and Joining, volume 33, issue 3, 2015, Pages 19~24
DOI : 10.5781/JWJ.2015.33.3.19
Joint properties of electric control unit (ECU) module using Sn-Cu-(X)Al(Si) lead-free solder alloy were investigated for automotive electronics module. In this study, Sn-0.5Cu-0.01Al(Si) and Sn-0.5Cu-0.03Al(Si) (wt.%) lead-free alloys were fabricated as bar type by doped various weight percentages (0.01 and 0.03 wt.%) of Al(Si) alloy to Sn-0.5Cu. After fabrications of lead-free alloys, the ball-type solder alloys with a diameter of 450 um were made by rolling and punching. The melting temperatures of 0.01Al(Si) and 0.03Al(Si) were 230.2 and
, respectively. To evaluation of properties of solder joint, test printed circuit board (PCB) finished with organic solderability perseveration (OSP) on Cu pad. The ball-type solders were attached to test PCB with flux and reflowed for formation of solder joint. The maximum temperature of reflow was
for 50s above melting temperature. And then, we measured spreadability and shear strength of two Al(Si) solder materials compared to Sn-0.7Cu solder material used in industry. And also, microstructures in solder and intermetallic compounds (IMCs) were observed. Moreover, thickness and grain size of
IMC were measured and then compared with Sn-0.7Cu. With increasing the amounts of Al(Si), the
thickness was decreased. These results show the addition of Al(Si) could suppress IMC growth and improve the reliability of solder joint.
Validation of sequence test method of Pb-free solder joint for automotive electronics
Kim, A Young ; Oh, Chul Min ; Hong, Won Sik ;
Journal of Welding and Joining, volume 33, issue 3, 2015, Pages 25~31
DOI : 10.5781/JWJ.2015.33.3.25
Due to environmental regulations (RoHS, WEEE and ELV) of the European Union, electronics and automotive electronics have to eliminate toxic substance from electronic devices and system. Specifically, reliability issue of lead-free solder joint have an increasing demand for the car electronics caused by ELV banning. The authors prepared engine control unit and cabin electronics soldered with Sn-3.0Ag-0.5Cu (SAC305). To compare with the degradation characteristics of solder joint strength, thermal cycling test (TC), power-thermal cycling test (PTC) and series tests were conducted. Series tests were conducted for TC and PTC combined stress test using the same sample in sequence and continuously. TC test was performed at
and soak time 10 min for 1000 cycles. PTC test was applied by pulse power and full function conditions during 100 cycles. Combined stress test was tested in accordance with automotive company standard. Solder joint degradation was observed by optical microscopy and environment scanning electron microscopy (ESEM). In addition, to compare with deterioration of bond strength of quad flat package (QFP) and chip components, we have measured lead pull and shear strength. Based on the series test results, consequently, we have validated of series test method for lifetime and reliability of Pb-free solder joint in automotive electronics.
Epoxy solder paste and its applications
Moon, Jong-Tae ; Eom, Yong-Sung ; Lee, Jong-Hyun ;
Journal of Welding and Joining, volume 33, issue 3, 2015, Pages 32~39
DOI : 10.5781/JWJ.2015.33.3.32
With the simplicity of process and high reliability in chip or package bonding, epoxy solder paste (ESP) has been recently considered as a competitive bonding material. The ESP material is composed of solder powder and epoxy formulation which can remove oxide layers on the surface of solder powder and pad finish metal. The bonding formed using ESP shows outstanding bonding strength and suppresses electrical short between adjacent pads or leads owing to the reinforced structure by cured epoxy after the bonding. ESP is also expected to suppress the formation and growth of whisker on the pads or leads. With the mentioned advantages, ESP is anticipated to become a spotlighted bonding material in the assembly of flexible electronics and electronic modules in automotive vehicles.
A study on the analysis effectiveness of the virtual welding simulator for welding manpower development
Choi, Eugene ; Kim, Jung-Yeong ; Shin, Sang-Ho ; Kim, Sang-Yeol ;
Journal of Welding and Joining, volume 33, issue 3, 2015, Pages 40~46
DOI : 10.5781/JWJ.2015.33.3.40
Welding is one of the most fundamental and necessary work in the industry that demand sophistication of skilled workers. This study is to introduce welding simulator as a training tool, to verify its effectiveness and to measure satisfaction of the trainees. A group of freshman students at a Korea Polytechnics College in their twenties with less experience of welding participated in the study. They were divided into two groups and took a traditional training course (comparison group) and a training course with welding simulator applied reality/haptic technology (experimental group) for same hours respectively. To evaluate training effect, a national certificate test and a survey based on Phillips' ROI (Return on Investment) methodology were conducted by the students and the college respectively. And satisfaction survey among the students based on Kirkpatrick's Four-Level Evaluation Model was also carried out. The results showed that all students in the experimental group passed the national certificate test and the ROI of the experimental group for five years were 110% higher than the comparison group. Furthermore, 25% more students in the experimental group replied "very satisfied" about the overall training course and 75% more students in the same group found that the simulation was very similar to the real welding.
Chlorine effect on ion migration for PCBs under temperature-humidity bias test
Huh, Seok-Hwan ; Shin, An-Seob ;
Journal of Welding and Joining, volume 33, issue 3, 2015, Pages 47~53
DOI : 10.5781/JWJ.2015.33.3.47
By the trends of electronic package to be more integrative, the fine Cu trace pitch of organic PCB is required to be a robust design. In this study, the short circuit failure mechanism of PCB with a Cl element under the Temperature humidity bias test (
/85%RH/3.5V) was examined by micro-structural study. A focused ion beam (FIB) and an electron probe micro analysis (EPMA) were used to polish the cross sections to reveal details of the microstructure of the failure mode. It is found that
were formed and grown on Cu trace during the
/3hrs and that
was decomposed into Cu dendrite and
gas during the
/85%RH/3.5V. It is suggested that Cu dendrites formed on Cu trace lead to a short circuit failure between a pair of Cu traces.
Effects of laser power on hardness and microstructure of the surface melting hardened SKD61 hot die steel using Yb:YAG disk laser
Lee, Kwang-Hyeon ; Choi, Seong-Won ; Kang, Chung-Yun ;
Journal of Welding and Joining, volume 33, issue 3, 2015, Pages 54~61
DOI : 10.5781/JWJ.2015.33.3.54
In this study, effect of laser power on hardness and microstructure of SKD61 Hot Die steel of which surface was melted and hardened with Yb:YAG disk laser was investigated. Beam speed was fixed at 70 mm/sec and distance between them was 0.8 mm about Laser surface melting. The only thing that was changed laser power. Laser powers were 2.0, 2.4 and 2.8 kW. No defect was found under all conditions. As the laser power increased, the penetration depth were deepened and the bead width was also widened. There was no hardness deviation of fusion zone at same laser power and it was higher than that of heat affected zone. In addition, the more laser power increased, the more hardness in fusion zone decreased. Fusion zone was macroscopically dendrite structure. However, core matric in dendrite was lath martensite of 100 nm size. There were
of 500 nm and the VC and
of a nano meters on boundary of dendrite.
A weld-distortion analysis method of the shell structures using ultra structural FE model
Ha, Yunsok ; Yi, Myungsu ;
Journal of Welding and Joining, volume 33, issue 3, 2015, Pages 62~67
DOI : 10.5781/JWJ.2015.33.3.62
A very large shell-structure built in shipyards like ship hulls or offshore structures are joined by welding through full process. As the welding contains a high thermal cycle at a local area, the welded structures should be distorted unavoidably. Because a distorted ship block should be revised to the designed value before the next stage, the ability to predict and to control the weld distortion is an accuracy level of the yard itself. Despite the ship block size, several present thermal distortion methodologies can deal those sizes, but it is a different story to deal full ship size model. Even a fully constructed ship hull not remaining any welding can have an accuracy issue like outfitting installation problems. Any present thermal distortion methodology cannot accept this size for its recommended element size and the number. The ordinary welding breadth at erection stage is about 20~40 mm. It can hardly be a good choice to make finite element model of these sizes considering human effort and computational environment. The finite element model for structure analysis of a ship hull is prepared at front-end engineering design stage which is the first process of the project. The element size of the model is as fine as the longitudinal space, and it is not proper to obtain a weld distortion at the erection stage. In this study, a methodology is suggested that a weldment can be shrunk at original place instead of using structural finite element model. We cut the original shell elements at erection weld-line and put truss elements between the edges of cut elements for weld shrinkage. Additional truss elements are used to facsimile transverse weld shrinkage which cannot be from the weld-line truss element shrink. They attach to weld-line truss element like twigs from barks. The capacity of developed elements is verified through an accuracy check of erection process of a container vessel at the apt. hull. It can be a useful tool for verifying a centering accuracy after renew and for block-separating planning considering accuracy.
A study of model for nitrogen permeation in TIG welding of super duplex stainless steel
Lee, Jae-Hyoung ; Jung, Byong-Ho ; Cho, Sang-Myung ; Jun, Jae-Ho ;
Journal of Welding and Joining, volume 33, issue 3, 2015, Pages 68~74
DOI : 10.5781/JWJ.2015.33.3.68
Superduplex stainless steels are important materials to the oil and gas industry, especially for off-shore production. TIG welding of super duplex stainless steels to obtain the optimal phase balance between austenite and ferrite is mainly achieved by controlling the cooling rate and the weld chemistry. The latter depends on the filler wire chosen and the shielding gas used. If TIG welding of superduplex stainless steels is performed with argon shielding gas only, then nitrogen gets lost from the weld pool, which can result in a ferrite-rich weld metal, with an inferior corrosion resistance than parent metal. In the present study, nitrogen permeation model from the shield gas which gets into the weld metal in DCEN-TIG welding has suggested. This plasma stream model shows characteristics of permeation of nitrogen ions into the molten metal due to the strong physical effect of plasma stream which formed by the arc pressure rather than the permeation of nitrogen ions caused by electric effect.
Design of self-piercing rivet to joint in advanced high strength steel and aluminium alloy sheets
Kim, Dongbum ; Qiu, Yuangen ; Cho, Hae-Yong ;
Journal of Welding and Joining, volume 33, issue 3, 2015, Pages 75~80
DOI : 10.5781/JWJ.2015.33.3.75
Self-piercing riveting is an joining method of advanced high strength steels (AHSS) and other dissimilar materials. It has attracted considerable interest from the automotive industry. The SPR has become an interesting alternative joining technique for difficult to weld materials such as steels and aluminium alloys. In this paper, self-piercing rivet and anvil for SPR were designed for the joining conditions with AHSS and aluminium alloy. Various conditions of SPR were simulated for the design of rivets and anvils. The simulated results were in good agreement with experimental ones. As a result, over HV500 rivet is desirable to joint SPFC780 AHSS and aluminum alloy.