• Proceedings of the KWS Conference
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• 2004.05a
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• pp.129-130
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• 2004

The stainless steel sheet which is one of primary barrier components for membrane on LNG ship is ordinarily welded by either TIG or PAW. The weld shapes of acceptant tolerance for membrane construction are scripted by G.T.T.(Gaztransport ＆ Technigaz)‘s rules such as penetration depth, weld throat and weld length etc. This paper presents relationship between weld metal shear strength and weld penetration formed with plasma arc welding. The results show penetration depth is not decisive factor on shear strength, but weld throat and length.

• Journal of Ocean Engineering and Technology
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• v.10 no.1
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• pp.36-46
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• 1996

This paper deals with determinig the proper friction welding condition and analyzing various mechanical properties of friction welded joints of sintered carbide tool materials(K20, P25, and SKDX5 for the blade part of drill or press punch) to alloy steel (SKH4, SCM440 for the shank part of drill or press punch), the alloy steel to aluminum(A6061 for the interlayer material between the blade part and the shank) and sintered carbide tool materials to alumminum. And also acoustic emission test will be carried out during fiction welding to evaluate the weld quality.

• Journal of Mechanical Science and Technology
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• v.15 no.1
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• pp.52-60
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• 2001

In this paper, as a new measurement method to estimate the change of material condition, the simplified ultrasonic CT system, which uses the information of three directions, that is, $90^{\circ}$, $+45^{\circ}C$and $-45^{\circ}C$ about inspection plane is proposed. Use of simplified CT system has two merits: Firstly, the measurement time is very short compared with general CT. Secondly, it can detect sensitively small defect in vertical or slant direction about inspection plane because the obtained image is CT image calculated from three directions. From these merits, this method can be considered as an effective method to evaluate material conditions. The basic performance of the proposed method was confirmed through several specimens with several simple defects. In order to confirm the applicability of actual NDT, several kinds of welded specimens are investigated. The result showed that the CT image obtained had good agreement with actual defect of specimens.

• Journal of Welding and Joining
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• v.8 no.3
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• pp.53-59
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• 1990

Temperature distribution of thick plate during welding was investigated. Applied weldng process was shielded metal arc welding which was known as one of the most utilized processes in fabrication fields. Heating and cooling cycles were recorded by imploying high fidelity recorded and K-type thermocouple of 0.3mm in diameter. Both analytical and numerical calculations were preformed so as to verify the thermal cycle measurement. Results showed that the temperature of a welded points at given time could be predicted by the theoretical calculations. It was considered that methods could be applied to real structural components with slight modification.

• Journal of Welding and Joining
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• v.12 no.3
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• pp.101-108
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• 1994

The horizontal continuous casting process with the heating mold was adopted for fabricating defect-free 4043 Al alloy rods of 3.2m dia. with mirror surfaces. These rods were drawn into 2.4mm dia. rods for GTAW welding. The GTAW welding tests were carried out by use of these welding rods with 6061 Al alloy as a base metal. After welding, the X-ray tests, tensile strength tests, bending tests, and microstructural analysis of welded zone and HAZ were carried out. The results represented that the welding rods with good surfaces and welding properties could be made by the horizontal continuous casting, and followed by the drawing process.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.7
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• pp.147-155
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• 2000

To reduce the noise from wood cutting saw at the saw mill(lumber mill) or a construction area, some multi-layer sandwich saw blades which a aluminum or copper plate was inserted between the two steel plates were developed and were tested of the wood cutting noise level at various test places. From the research, it was found that the multi-layer saw blade with copper or aluminum plate between steel plates and spot welded 60 points could reduce the wood cutting sound level about 8.3 dB(97.031 dB - 88.743 dB) at indoor test and 3.8 dB(84.805 - 81.638 dB) at field test.

• Proceedings of the KWS Conference
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• 1999.05a
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• pp.215-218
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• 1999

With increasing demand of energy saving, -many efforts were made to employ aluminium alloys in the automobile industry. Especially, resistance spot welding has been widely used in the steel metal joining process because of its high productively and convenience. In this paper, spot weldability of 7075-T6 aluminium thin sheets for various welding conditions were examined by series of experiments. The tensile shear strength and microstructure of welded specimens was observed, and The optimal welding conditions were found for each welding conditions.

• Proceedings of the KWS Conference
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• 2003.05a
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• pp.84-86
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• 2003

The laser welding and its analysis of thin-sheet carbon steels were carried out with high power CO$_2$1aser. Bead on plate welding of thin sheet was examined to investigate the effect of weld variables of laser welding, and to obtain optimum welding condition. Butt-welding was also carried out to show the effect of gap on the laser weldability of thin sheet. At high welding speed, the partial penetration was obtained by low heat input. Otherwise, porosity was formed in the bead at low weld speed because of too many heat input. The maximum gap tolerance on laser welding was observed to be about 0.2mm. This gap size has good relationship with beam size of laser spot(about 0.3mm). The formability of welded sheet was about 80% value of base metal and the gap size has not affected on the formability, although weld quality is dependent on the gap size.

• Proceedings of the KWS Conference
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• 2005.11a
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• pp.189-191
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• 2005

Dissimilar joining of AI 6013-T4 alloys and austenite stainless steel was carried out using friction stir welding technique. Microstructures near the weld zone and mechanical properties of the joint have been investigated. Microstructures in the stainless steel side and AI alloy were depended on the thermo-mechanical condition which they received. TEM micrographs revealed that the interface region was composed of the mixed layers of elongated stainless steel and ultra-fine grained AI alloy and intermetallic compound layer which was identified as the $Al_{4}Fe$ with hexagonal close packed structure. Mechanical properties were lower than those of 6013 AI alloy base metal, because tool inserting location was deviated to AI alloy from the butt line, which resulted in the lack of the stirring.

• Journal of Welding and Joining
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• v.31 no.5
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• pp.41-46
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• 2013

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.