• Korean Journal of Materials Research
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• v.13 no.12
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• pp.850-854
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• 2003

The abrasion wear behavior on the hardfacing weld was investigated by performing abrasion wear, hardness, and microstructural tests. The gas metal arc(GMA) weld was produced by using the cored wire which was filled with the hard metal, i.e., the recycled tungsten carbide (WC) reinforced metal matrix composite. For 30% addition of the hard metal, the abrasion wear resistance was significantly improved comparing with that for 20% addition of the hard metal. Above 30% addition of the hard metal, however, there was no significant improvement of the wear resistance. The improvement of the wear resistance was due to the increased amount of eutectic carbides(W$_{6}$C) which was formed during GMA welding. For the weld in which the hard metal was added to 30-40%, an optimum level of abrasion wear resistance was performed.

• Proceedings of the KAIS Fall Conference
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• 2003.06a
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• pp.122-124
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• 2003

본 연구는 사출성형공정 후 조립공정에서 발생하고 있는 사출성형물의 Weld line에 의한 사출성형물의 파괴현상을 해석하고 개선된 품질을 얻기 위한 시도이다. 사출성형 관련 설계는 사출금형설계 전문가의 축적된 지식과 경험을 활용하여 수행되어 왔으며, 설계에 필요한 설계자의 경험이 전무한 경우 많은 시행 오차를 유발하고 있는 실정이다. 본 연구에서는 글라스 홀더 플레이트를 사출성형하고 조립공정을 수행함에 있어 생산 중 발생되고 있는 Weld line에 의한 제품의 강도 문제를 수치해석을 통하여 시뮬레이션함으로써 제품 품질을 향상 하고자 해석과 평가를 시도 하였다.

• Proceedings of the KAIS Fall Conference
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• 2003.06a
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• pp.133-135
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• 2003

본 연구는 사출성형공정상에서 발생하고 있는 사출성형물의 Weld line에 의한 외관 불량을 해석하고 개선된 품질을 얻기 위한 시도이다. 사출성형 관련 설계는 사출금형설계 전문가의 축적된 지식과 경험을 활용하여 수행되어 왔으며, 설계에 필요한 설계자의 경험이 전무한 경우 많은 시행 오차를 유발하고 있는 실정이다. 본 연구에서는 Window Panel의 사출성형을 수행함에 있어 생산 중 발생되고 있는 Weld line에 의한 제품 외관의 문제를 수치해석을 통하여 시뮬레이션함으로써 제품 품질을 향상 하고자 해석을 시도하였다.

• Journal of the Institute of Convergence Signal Processing
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• v.21 no.4
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• pp.209-215
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• 2020

In this paper, we propose an algorithm for segmenting weld bead images using edge enhancement and active contours. In the proposed method, high-frequency filtering and contrast improvement are performed for edge enhancement, and then, by applying the active contour method, only the weld bead region can be obtained. The proposed algorithm detects an edge through high-frequency filtering and reinforces the detected edge by using contrast enhancement. After the edge information is improved in this way, the weld bead area can be extracted by applying the active contour method. The proposed algorithm shows better performance than the existing methods for segmenting the weld bead in the image. For the objective reliability of the proposed algorithm, it was compared with the existing high pass filtering methods, and it was confirmed that the welding bead segmentation of the proposed method is excellent. The proposed method can be usefully used in evaluating the quality of the weld bead through an additional procedure for the segmented weld bead.

• Design & Manufacturing
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• v.9 no.2
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• pp.10-15
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• 2015

The water has been the suitable for the cooling medium until now. But the water as cooling medium seem to have the limit for high speed injection. The steam plastic molding injection use the steam as the medium when raise the mold temperature. The weld line has been the major quality problems in a plastic injection parts to be difficult to be solved. These problems in injection-molded plastic parts are difficult to find the reason because these issues are usually in tradeoff realtions with each other. The purpose of this paper is to obtain the optimum injection moulding condition for improving the quality of plastic injection parts and to inquire the productivity improvement with the measured cycle time by steam plastic moluding injection. Based on these numerical results, the guidelines of mould design and injection processing condition were established. As a result, the improvement of quality and the reduction of cycle time was achieved.

• Journal of Ocean Engineering and Technology
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• v.22 no.2
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• pp.58-64
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• 2008

Large-scale tests of welded tubular K-joint sunder balanced in-plane bending braces were carried out to observe the fatigue behavior of the API 2W Gr.60 steel plate produced by POSCO. Toe grinding and weld profiling were used to improve the fatigue life of a tubular K-joint. The effects of the steel grade and chord wall thickness on the fatigue life were also investigated. The present results were compared with the UK DEn design curve.

• Journal of Welding and Joining
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• v.30 no.1
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• pp.5-7
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• 2012

• Journal of Welding and Joining
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• v.23 no.4
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• pp.66-72
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• 2005

An electromagnetic inductive sensor consisted of one exciter and three separated (triple) detectors has been developed for both tracking the weld seam of a workpiece and controlling the sensor-to-workpiece distance (height) simultaneously. The left and right detectors are used to track the seam, while the fore and the other two detectors allow the sensor to determine the height and the gap width by being coupled their outputs together. A series of experiments with the proposed sensor located above a mild steel plate containing a weld seam of gap are carried out to examine the feasibility of the sensor. The results revealed that the proposed sensor could fairly well track the desired seam and also well control the height to be constant even when the gap width of the seam varied. The gap width can be also determined during the seam tracking by using the sensor outputs. As a consequence, these can provide the developed sensor with substantial improvement for industrial uses with respect to the previous electromagnetic sensors being used for the weld seam tracking.

• Journal of Korean Society of Steel Construction
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• v.23 no.2
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• pp.137-146
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• 2011

In the fabrication of steel bridges, blast cleaning prior to painting is carried out on the steel members to clean the forged surface and to increase the adhesive property of the applied painting systems. The effect of blast cleaning on the fatigue strength improvement of the weld joints, however, is not clear. In this study, Almen strips and steel specimens were blast-treated, conforming to ten types of blast-cleaning conditions deducted from the blast-cleaning conditions of seven steel structure fabrication companies. The arc height, roughness, hardness, and compressive residual stress were measured before and after the implementation of the ten blast-cleaning methods, and the relationship between the blast conditions and the measured values was studied. The geometry of the weld toe and the compressive residual stress near the weld toe were also measured before and after the blast cleaning of the butt-welded joints, and fatigue tests were carried out on the butt weld joints. The test results showed that blast cleaning significantly increases the fatigue strength and limit.

• Proceedings of the KWS Conference
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• 2005.06a
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• pp.256-258
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• 2005