• Laser Solutions
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• v.3 no.2
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• pp.45-51
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• 2000

In this paper, the possibilities and the limits of the laser seam welding were studied to utilize the advantageous properties of amorphous metal foils. For the conventional welding method, the high heat transfer makes the crystallized zone of the work material unavoidable. The laser is able to weld the amorphous metal without a crystallized zone, because heat transfer is limited within a very small restricted volume. The crystallized zone is restricted in the neighbor of welding spot and not in the melting area. This can be proved directly by the etching and indirectly by the tensile shear test, micro hardness test and bending test. The overlapping of welding bead could form the formation of wider and thicker amorphous zone.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.6 no.3
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• pp.73-81
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• 1997

This study was to find the best adhesive condition comparing mechanical property in case of hot-melt adhesion using glue-gun, ultrasonic welding with adhesion and only ultrasonic welding in order to adhere thermoplastic resin of polyethylene (PE) in which reliable adhesion was resulted in case of ultrasonic welding with same materials of PE. The best welding condition were acquired at welding time 1 second, welding pressure 250kPa for PE-PE where welding time and welding pressure were increased in accordance with the increase of material strength. At the best ultrasonic welding conditions, bonding strength of PE-PE welding was about 21MPa of which material have tensile strength of 24MPa. Through the analysis of microscophic test for ultrasonic welding structure, it was distinguished between well welded structure with higher intermolecule flow and bad welded structure with lower flow, of which result is mostly correspond with the result of tensile strength test.

• Journal of Welding and Joining
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• v.33 no.1
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• pp.87-93
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• 2015

This study was performed to develop repair technology for J-Groove dissimilar metal weld of pressurizer heater sleeve in nuclear power plants. Pad, J-Groove automatic welding and mechanical machining equipments to develop repair technology using 'Half Nozzle Repair' were designed and manufactured. To obtain the optimum welding process parameters during Pad temperbead overlay welding, several welding experiments using Taguchi method were conducted. Weldability of Pad overlay weld specimens was estimated by PT/RT test, FE-SEM, EDS and Vickers hardness test. Also, J-Groove welding to adjust weld shape conditions requiring in ASME Code was carried out and its integrity of weld specimens was evaluated through PT/RT test and optical microscope. Consequently, it was revealed that Pad and J-Groove overlay welding for dissimilar metal weld of pressurizer heater sleeve could be possible to meet Code standard without weld defect.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1377-1380
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• 2008

An irradiation test of a nuclear fuel rod having external and internal tube structure was planned for a performance. To establish fabrication process satisfying the requirements of irradiation test, micro-TIG welding system for fuel rods was developed, and preliminary welding experiments for optimizing process conditions of fuel rod was performed. Fuel rods with 15.9mm diameter and 0.57mm wall thickness of cladding tubes and end caps have been used and optimum conditions of endcap welding have been selected. In this experiment, the qualification test was performed by tensile tests, helium leak inspections, and metallography examinations to qualify the endcap welding procedure. The soundness of the welds quality of a dual cooled fuel rods has been confirmed by mechanical tests and microstructural examinations.

• Proceedings of the KWS Conference
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• 2005.06a
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• pp.106-108
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• 2005

The instrumented fuel irradiation test at a research reactor is needed to evaluate the performance of the developed nuclear fuel. The fuel elements can be designed to measure the center line temperature of fuel pellets during the irradiation test by using temperature sensor. The thermal sensor was composed of thermocouple and sensor sheath. Micro-laser welding technology was adopted to seal between seal tube and sensor sheath with thickness of 0.15 mm. The soundness of welding area has to be confirmed to prevent fission gas of the fuel from leaking out of the element during the fuel irradiation test. In this study, fundamental data for micro-laser welding technology was proposed to seal temperature sensor sheath of the instrumented fuel element. And, micro-laser welding for dissimilar metals between sensor sheath and seal tube was characterized by investigating welding conditions. Moreover, the micro-laser welding technology is closely related to advanced industry. It is expected that the laser material processing technology will be adopted to various a pplications in the industry.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.5
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• pp.771-777
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• 2006

Recently regulations which make it mandatory to use the environment-friendly goods are increaing in automobiles. In this study the TIG autogenous welding process was developed by solving the problem of previous spot welding of side part and the ceramic protection Jig was developed for the welding of fragile glass ball. And the optimal process parameter was selected by complementing the demerit of the previous filler material welding to fill up the bottom part. Finally the lamp aging test and earthquake resistant test was done to check the reliability of welded brake lamp.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.20 no.4
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• pp.484-489
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• 2011

Nowadays, the automobile manufactures make a great efforts to reduce manufacturing cost, body weight and to develop eco-environmental parts in order to be more competitive and solve global warming. For these reasons, materials of automobile's parts are changed over from general carbon steel and stainless steel to plastic and Aluminum. And, laser welding technology is introduced to apply welding between aluminum parts. In this paper, the data of laser welding parameters is collected through lots of the experiment according to the material, welding speed and laser power to apply laser welding in Aluminum fuel filler neck assembly. After manufacturing prototype of aluminum fuel filler neck, vibration durability test, tensile strength test and salt water test are applied to verify product's satisfied function.

• Transactions of Materials Processing
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• v.7 no.4
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• pp.400-406
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• 1998

The press formability analysis of welding parts was studied in the current work by the tailor welded blank. The press formability was tested by means of the flash weldability and the formability for two kinds of materials (SPCC & S35C). The results indicate that SPCC & S35C steel sheets showed good weldability and formability after an optimum welding conditions. The independent operation variables were characterized by strength of welding parts, deformation after the welding, press formability of welding parts and productibility of welding. The weldability and the quality of welding parts of the flashed SPCC steel sheet was superior to those of the S35C steel sheet, since a higher carbon content in steel sheet led to a higher hardness. The experimental results were discussed by the evaluation of the results obtained from tensile test, hardness test, micro-structure and V bending test.

• Journal of the Korea institute for structural maintenance and inspection
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• v.1 no.2
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• pp.107-113
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• 1997

Nondesructive test and structural analysis have been conducted to assess the safety of weld defective steel bridges in service. In the nondestructive test, using the radioactive ray and ultrasonic, the defective welding patterns in the steel bridges are identified. A major defective welding pattern is identified as the lack of welding area due to the insufficient welding penetration. By considering the welding defect in the above, structural analysis is conducted to evaluate the influence of welding defect on the safety of steel bridges. The results indicate that, due to the insufficient welding penetration, the stress obtained in the analysis is over the allowable fatigue stress level, and its influence on safety of the bridges is significant.

• Corrosion Science and Technology
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• v.10 no.3
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• pp.80-86
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• 2011

Welding was widely used in shipbuilding industries as a joining method. In present study, the effects of welding fume contaminated on steel surface on corrosion protection were examined by water ballast simulation test and condensation chamber test. Pull-off adhesion test, blistering test and cathodic disbondment test were carried out to evaluate the effects of residual welding fume. Consequently, it was clearly indicated that the residual welding fume didn't affect the corrosion protection of epoxy coated on steel when surface was treated by light sweep blasting to heavy sweep blasting which was applied in this study.