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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 32, Issue 6 - Dec 2014
Volume 32, Issue 5 - Oct 2014
Volume 32, Issue 4 - Aug 2014
Volume 32, Issue 3 - Jun 2014
Volume 32, Issue 2 - Apr 2014
Volume 32, Issue 1 - Feb 2014
Selecting the target year
Evaluation of HIC/SSCC Resistance for API-X70 Pipe Manufactured by JCO Bending Process and SA Welding
Ryoo, Hoi-Soo ; Kim, Hee Jin ; Lee, Dong-Eon ;
Journal of Welding and Joining, volume 32, issue 5, 2014, Pages 1~6
DOI : 10.5781/JWJ.2014.32.5.1
This study aims at manufacturing SA welded API-X70 line-pipe with sour gas resistance. A pipe was manufactured by JCO bending process and SA welding using the API-X70 plate guaranteed HIC resistance. SA welded pipe was expanded in order to reduce the residual stress. The evaluation of a pipe for resistance to HIC and SSCC were performed by the RS D 0004 and RS D 0005 standards. For verification that a pipe has acceptable resistance to HIC, fullscale test was carried out. Results showed no cracking for the HIC and SSCC.
The Effects of Welding Wires on the Weldabilities of API X-100 with Laser-Arc Hybrid Welidng
Kim, Sungwook ; Lee, Mok-Young ;
Journal of Welding and Joining, volume 32, issue 5, 2014, Pages 7~12
DOI : 10.5781/JWJ.2014.32.5.7
In this study, API-X100 steel pipes were welded with various kinds of welding wires in the laser-arc hybrid welding process. 10kW fiber laser source was combined to MIG arc welding process. API X-100 steel of base metal was of 16.9mm thickness, and butt welding applied. After welding, full penetration weld was acquired by 1-pass welding. A root porosity and the lack of fusion was observed in some welding conditions. By the mixing the melted wire, acicular ferrite, polygonal ferrite, pro-eutectoid, aligned side plate, and bainite structures were observed at the weld metal. From the observation of hybrid weld, unmixed zone had more Ni and Cr. The unmixed zone was a 1/3 area of the weld metal. As the mechanical test of the hybrid welding, tensile test and impact test applied. From the tensile test, all of the welding except SM70S was fractured at the base metal. The result of the impact test at -30 degree C led 60J~320J of the absorbed energy. The result of the low-absorbed energy might be from the coarse equiaxed structures of the weld metal.
A Review of Corrosion and Hydrogen Diffusion Behaviors of High Strength Pipe Steel in Sour Environment
Kim, Sung Jin ; Kim, Kyoo Young ;
Journal of Welding and Joining, volume 32, issue 5, 2014, Pages 13~20
DOI : 10.5781/JWJ.2014.32.5.13
A brief overview is given of the corrosion and hydrogen diffusion behaviors of high strength pipe steel in sour environment. Firstly, hydrogen adsorption and diffusion mechanism of the pipe steel is introduced. Secondly, the effect of iron sulfide film precipitated as a result of the corrosion reaction on the steel surface on hydrogen reduction reaction and subsequent hydrogen permeation through the steel is discussed. Moreover, the hydrogen diffusion behavior of the pipe steel under tensile stress in both elastic and plastic ranges is reviewed based on a number of experimental permeation data and theoretical models describing the hydrogen diffusion and trapping phenomena in the steel. It is hoped that this paper will result in significant academic contributions in the field of corrosion and hydrogen related problems of the pipe steel used in sour environment.
Development Trend of Sour Resistant Linepipe Steel and its Sour Characteristics in Welded Joints
Kim, Young-Hune ; Song, Woo-Hyun ; Koh, Seong-Ung ;
Journal of Welding and Joining, volume 32, issue 5, 2014, Pages 21~25
DOI : 10.5781/JWJ.2014.32.5.21
Oil and gas fields were left unexploited which deemed too deep and sour. New developing markets are emerging in this part and pipe manufacturers need demanding requirements in the combination of sour service requirements with heavier wall thickness required to cope with increasing water depths. Whilst, the strength and fracture toughness needed to meet the strict requirements In order to deliver the optimum sour properties in the final pipe, attention needs to be paid to each stage throughout the process from steel making. The main key during steel making is strengthening, securing mechanical properties and suppression of center segregation by adding proper chemical elements and controlling water cooling and plate rolling. Additionally in welding, it is required to prevent HAZ softening by high heat input during welding of heavy thick pipes and hydrogen assisted cracking in high strength steels with hard phases. In this paper, we introduce markets of sour resistant linepipe steels and in response to this, have a look in the development trend of sour resistant linepipe steels and its sour characteristics in welded joints.
Welding Characteristics of A-TIG Using Various Compositions of Active Fluxes
Kim, Bong-Hun ; Gong, Yong-Soo ;
Journal of Welding and Joining, volume 32, issue 5, 2014, Pages 26~31
DOI : 10.5781/JWJ.2014.32.5.26
Conventional TIG(C-TIG) welding process guarantees higher quality weldment when compared with other processes. However, C-TIG with inherent low penetration shows disadvantages in productivity, especially for thick-walled structure. To overcome these handicaps, active-flux TIG(A-TIG) welding has been introduced and studied widely in a motivation to improve both quality and productivity. Present study made a focus on optimum combination of oxide components to enhance arc contraction and penetration. Results indicated that arc contraction inducing enhancement of penetration could be possible when composition of active fluxes was well matched with base metal.
A Study of the Effect of Magnetic Fields Using Welding Process
Cho, Hong Seok ; Park, Ik Keun ; Lee, Wooram ;
Journal of Welding and Joining, volume 32, issue 5, 2014, Pages 32~43
DOI : 10.5781/JWJ.2014.32.5.32
Welding and joining technology has become a core field. Therefore it is more widely applied to nonferrous metals, inorganic and polymeric materials. That is because the high performance, high function and diversification trend of materials used as industrial technology develops. In the laser welding process, STS 304 and SCP1-S were used as the base materials, the output density was fixed
, the protective gas was argon(Ar) and the transfer rate was fixed 5 mm/sec. and it was progressed while the magnetic field is gradually increasing by 100 mT ranging 0 to 400 mT. The tensile test showed in average about 6 % tensile strength improvement in the case of the laser welding process using the magnetic fields. In the shielded metal arc welding process using SPHC only or the combination of SPHC+STS304 as base materials. The electric current was set at 80 Amperes and the protective gas used argon(Ar) the same as the laser welding process and the strength of magnetic fields. In the shielded metal arc welding process using the magnetic fields, the tensile tests showed about 5 % tensile strength improvement in the case of using SPHC only, 3 % tensile strength improvement in the case of using the combination of SPHC+ STS304. In comparing the results of numerical analysis to the results of experimental tests, it was revealed that the temperature, thermal stress distribution and the behavior of molten pool were similar to those of real tests. Consequently, it may be considered that the numerical assumption and the analytical model used in this study were reasonable.
Mechanical Behavior of Weldbond Joint of 1.2GPa Grade Ultra High Strength TRIP Steel for Car Body Applications
Lee, Jong-Dae ; Lee, So-Jeong ; Bang, Jung-Hwan ; Kim, Dong-Cheol ; Kang, Mun-Jin ; Kim, Mok-Soon ; Kim, Jun-Ki ;
Journal of Welding and Joining, volume 32, issue 5, 2014, Pages 44~49
DOI : 10.5781/JWJ.2014.32.5.44
The effect of weldbond hybrid joining process on the mechanical behavior of single lap and L-tensile joints was investigated for the newly developed 1.2GPa grade ultra high strength TRIP(transformation induced plasticity) steel. In the case of single lap shear behavior, the weldbond joint of 1.2GPa TRIP steel showed lower maximum tensile load and elongation than that of the adhesive bonding only. It was considered to be due to the reduction of real adhesion area, which was caused by the degradation of adhesive near the spot weld, and the brittle fracture behavior of the spot weld joint. In the case of L-tensile behavior, however, the maximum tensile load of the weldbond joint of 1.2GPa TRIP steel was dramatically increased and the fracture mode was change to the base metal fracture which is desirable for the spot weld joint. These synergic effect of the weldbond hybrid joining process in 1.2GPa TRIP steel was considered to be due to the stress dissipation around the spot weld joint by the presence of adhesive which resulted in the change of crack propagation path.
Defect Detection in Friction Stir Welding by Online Infrared Thermography
Kryukov, Igor ; Hartmann, Michael ; Bohm, Stefan ; Mund, Malte ; Dilger, Klaus ; Fischer, Fabian ;
Journal of Welding and Joining, volume 32, issue 5, 2014, Pages 50~57
DOI : 10.5781/JWJ.2014.32.5.50
Friction Stir Welding (FSW) is a complex process with several mutually interdependent parameters. A slight difference from known settings may lead to imperfections in the stirred zone. These inhomogeneities affect on the mechanical properties of the FSWed joints. In order to prevent the failure of the welded joint it is necessary to detect the most critical defects non-destructive. Especially critical defects are wormhole and lack of penetration (LOP), because of the difficulty of detection. Online thermography is used process-accompanying for defect detecting. A thermographic camera with a fixed position relating to the welding tool measures the heating-up and the cool down of the welding process. Lap joints with sound weld seam surfaces are manufactured and monitored. Different methods of evaluation of heat distribution and intensity profiles are introduced. It can be demonstrated, that it is possible to detect wormhole and lack of penetration as well as surface defects by analyzing the welding and the cooling process of friction stir welding by passive online thermography measurement. Effects of these defects on mechanical properties are shown by tensile testing.
A Study on the Production Process Management Support System for Smart Shipyard Based on Mobile
Park, Ju-Yong ; Oh, Hyoung-Seok ; Lee, Dong-Kun ;
Journal of Welding and Joining, volume 32, issue 5, 2014, Pages 58~64
DOI : 10.5781/JWJ.2014.32.5.58
The shipbuilding industry is facing the various problems of less demand and oversupply owing to the global economic crisis and the increase in shipbuilding countries. Shipyards of the industry are making effort to strengthen their ability to handle the crisis via a smartwork technology for flexible working environment. In this study, we developed a smartwork system that manages the information in shipbuilding process with mobile devices such as smart phones and tablet PCs. To successfully apply the developed smartwork system to shipyards, we analyzed several best practices and management tasks of the shipbuilding processes. The developed system was designed by CBD approach that is a branch of service-oriented software engineering for reusability and flexibility on the system. As it is designed considering the flexible working environment, it supports to increase their productivity by reducing the time required to carry out tasks and by increasing the mobility required to manage work performance in field of shipyards.
Correlation of Microstructure and Tribological Properties of Mo Blended Fe-Base Coatings Fabricated by Atmospheric Plasma Spraying
Lee, Illjoo ; Park, Hyungkwon ; Lee, Changhee ;
Journal of Welding and Joining, volume 32, issue 5, 2014, Pages 65~71
DOI : 10.5781/JWJ.2014.32.5.65
Atmospheric plasma spraying (APS) is world-widely used process in the automotive industry as a method to provide wear resistance coatings for engine cylinder bore, using various materials. The weight of engine blocks can be considerably decreased by removing cast iron liners, which can finally result in the improvement of fuel efficiency. In this study, five kinds of powder materials, 1.2C steel powder and 1.2C steel powder mixed with 5, 10, 15, 20 wt.%. molybdenum powder, were deposited by atmospheric plasma spraying in order to investigate the effect of molybdenum on the wear resistance of coatings. Microstructural analysis showed that molybdenum splats were well distributed in 1.2C steel matrix with intimate bonding. The molybdenum added coatings showed better tribological properties than 1.2C steel coating. However, above the 15 wt.%. blending fraction, wear resistance was somewhat degraded with poor roughness of worn surface due to the brittle fracture occurred in molybdenum splats. Consequently, compared to conventional liner material, gray cast iron, 10 wt. pct. molybdenum blended 1.2C steel coating showed much better tribological properties and therefore it looks very feasible to replace gray cast iron liner.
Property Evaluation of Kinetic Sprayed Al-Ni Composite Coatings
Byun, GyeongJun ; Kim, JaeIck ; Lee, Changhee ; Kim, SeeJo ; Lee, Seong ;
Journal of Welding and Joining, volume 32, issue 5, 2014, Pages 72~79
DOI : 10.5781/JWJ.2014.32.5.72
Shaped charge(SC) ammunition is a weapon that penetrates directly the target by made jet from metal liner on impacting at a target. In SC, the liner occupies significantly important role causing an explosion and penetration of the target. The Al-Ni composite coating was deposited on copper liner in a solid state via kinetic spraying to improve the explosive force. The mechanical properties, reactivity and microstructure were investigated to confirm the possibility of kinetic sprayed Al/Ni composite coating as a reactive liner material. Reactive liner using Al/Ni composite exhibited much enhanced reactivity than pure copper liner due to Self-propagating High-temperature Synthesis (SHS) reaction with significantly improved adhesive bond strength. Especially, among the Al/Ni composite coatings, AN11 (the Al versus Ni atomic percent ratio is 1:1) showed the greatest reactivity due to its widest reaction area between deposited Al and Ni.
Fabrication of the Cu-STS-Cu Clad Metal for High Strength Electric Device Lead Frame and Thermal Stability on Their Physical Properties
Kim, Il-Gwon ; Son, Moon-Eui ; Kim, Young-Sung ;
Journal of Welding and Joining, volume 32, issue 5, 2014, Pages 80~86
DOI : 10.5781/JWJ.2014.32.5.80
We have successfully fabricated high strengthening Cu/STS/Cu 3 layered clad metal of
grade for electric device lead frame, and investigated thermal effect of the mechanical and physical properties on the Cu/STS/Cu 3 layered clad metal lead frame material at different temperatures ranging from RT to
. The fabricated clad metal shows a good thermal stability under 6% degrading of mechanical tensile strength and hardness change at
and also physical properties show stable thermal and electrical conductance of over
and 58.44% IACS upto the
. The results confirm that fabricated high strengthening Cu/STS/Cu 3 layered clad metal can be applied for the high performed electrical lead frame devices.