• Journal of Welding and Joining
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• v.9 no.3
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• pp.1-9
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• 1991

근래에 들어 국민들의 소득이 높아지고 생활수준이 향상됨에 따라 어려운 일은 하지 않으려고 하는 풍조가 사회전반에 걸쳐 만연되고 있다. 용접공정은 우리사회에서 가장 어렵고, 고된 일종의 하나로 인식되어 있고, 그 중에서도 특히 수도용 대형 강관의 용접시공은 열악한 작업현장 환 경과 전자세 용접등의 어려움 때문에 매우 높은 임금을 제시해도 용접공들사이에서 기피되는 대표적 사례이다. 따라서 앞으로의 원활한 상수도 공급을 위해서 긴급하게 요구되는 대형강관의 설치를 위해서는 용접공정의 자동화가 절실히 요구되는 실정이다. 이와 같은 문제의 해결을 위한 연구의 일환으로 선진국의 수도용 대형 강관 용접시공 방법 및 자동화의 현황을 파악하고, 우리나라의 용접시공 현황과 비교, 검토하여 현실에 적합한 수도용 강관의 용접시공 방법 및 자동화기법을 도출하기 위해서 미국, 이태리, 일본의 관계되는 회사들을 방문하였다. 이와 같은 해외방문목적을 요약하면 아래와 같다. 1) 선진국 대형 강관 용접시공의 현황파악 2) 수도용 대형 강관 용접시공자동화의 가능성 조사. 3) 대형 강관 용접시공 자동화를 위해서 필요한 장치들의 성능조사.

• Journal of Korean Association for Spatial Structures
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• v.11 no.4
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• pp.37-47
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• 2011

This article aims to analytically research for influence of residual stresses on bending moment responses against welded steel pipes subjected to quasi -static or dynamic loadings. The residual stresses of the welded steel pipe are computed by three-dimensional welding simulation. The bending moment responses of the welded and seamless steel pipes are determined by using three-dimensional dynamic elastoplastic FE analysis as a function of loading rate. It is seen from analytical results that the welded steel pipe shows lower moment response comparing to the seamless steel pipe, and moment difference between seamless and welded steel pipes tends to decrease as loading rate increases.

• Journal of Korean Society of Steel Construction
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• v.21 no.5
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• pp.515-526
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• 2009

There are three main production processes in the manufacture of concrete-filled square steel columns. The first process is known as the 'box-type process' or 'four-seam method,' wherein four beams are welded together at the seams. The second is the 'cold-forming process' or 'two-seam method,' wherein the seams of two channel beams are welded together. The third is the 'pressing process' or 'one-seam method,' wherein a circular column is pressed until it becomes a square column. In calculating the production cost for the making of a steel tube, it is very important to consider the welding process to be used and the desiredthickness of the steel tube, such as a square column that was developed under a new method, formed through the four-seam flare welding method at the center of the steel column width, following the L-shape formation. Certain tests were suggested in this study to evaluate the welding amount of concrete-filled square steel columns. With the parameters of the production method of a square steel column, the thickness of the steel square columns, and the welding amount, six specimens were produced. A structural test and finite-element analysis were conducted to assess the behavior of the steel column according to the water pressure inside the steel columns.

• Journal of Korean Society of Steel Construction
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• v.20 no.5
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• pp.645-653
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• 2008

Welded built-up square tubes are manufactured by flare welding at the center of the column width for cold-formed L-shaped four-piece plates and improved composite effect of concrete and steel by vertical inner anchor. Also, the axial resistance of concrete is increased by the thinness of the steel column, and the composite effect of concrete and steel prevents the steel column from local buckling. In this study, we introduced a manufacturing method of built-up square column steel square concrete-filled tubular column with vertical inner anchor and superior structural performance of the square stub column verified by the structural test for 15 specimens with parameters of shape of tube (built-up square tube, general steel tube), width over thickness of the steel tube (B/t=50, 58, 67) and the strength of concrete (f'c=10MPa, 50MPa).

• Journal of Welding and Joining
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• v.19 no.3
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• pp.261-266
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• 2001

본 고에서는 배관 재료일반과 용접공정에 대해 ERW강관을 중심으로 알아보았다. 국내 가스배관에서 ERW강관이 사용되는 것은 외경 24인치 이하 배관이며 그 이상 크기의 배관에서는 SAW강관이 사용된다. 배관의 안전성 및 건전성 확보를 위하여 가장 주의를 가지고 평가해야 할 대상은 손상 및 결함의 발생 비율이 가장 높은 심용접부 및 원주용접부 이다. 이들 배관 용접부의 건전성 확보를 위해서는 모재와는 다른 특성을 지닌 용접부위에서 다양한 금속학적, 역학적 인자들의 영향에 대한 정확한 분석과 평가를 실시하여야 한다. 용접부위 품질확보는 가스배관의 안전과 안정적운용에 반드시 필요한 부분이다.

• Journal of Welding and Joining
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• v.10 no.4
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• pp.98-102
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• 1992

이 글에서는 1. 강관제조 공정, 2. 적용용접기술, 3.국내외 용접기술 적용 현황 등에 관하여 다루었다.

• Journal of Welding and Joining
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• v.16 no.5
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• pp.45-47
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• 1998

고주파 전기 저항 용접법에 대한 연구는 매우 초보적인 단계에 머무르고 있어, 국내 강관 제조 업체의 국제 경쟁력을 확보하는데 장애가 되고 있는 상황이다. 그러나 최근 국내 강관제조 업체들이 많은 연구 노력을 경주하고 있고, 고주파 전기 저항 용접 공정의 모사 장치를 설치하여 연구 환경이 개선되고 있는 상황이다. 고주파 전기 저항 용접 공정의 신뢰성을 증가시키기 위해서는 고주파 전기 저항 용접 현상에 대한 기초적인 연구가 진행되고, 이에 근거한 공정의 자동화가 필수적으로 요구된다 하겠다.

• Journal of Korean Society of Steel Construction
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• v.13 no.4
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• pp.327-335
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• 2001

The characteristics and production mechanism of residual stress generated by multi-pass welding of the steel pipe were elucidated from the results of three-dimensional thermal elastic-plastic FEM analysis. When the steel pipe was jointed by multi-pass welding, the stress components of circumferential direction and radial direction near welded joints on the inner surface and the outer surface of the pope were tensile. The stress component of axial direction on the inner surface was tensile and on the outer surface was compressive. On the other hands, the production mechanism of residual stress generated by multi-pass welding of the steel pipe was investigated. Residual stress generated by welding of the steel pipe was investigated not only by the thermal history but also by geometrical shape. Then, the generality of the production mechanism of residual stress generated by multi-pass welding was confirmed.

• Journal of Korean Society of Steel Construction
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• v.28 no.2
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• pp.75-83
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• 2016

Existing tubes for concrete filled tubular structure are made through welding of four plates irrespective, but the production performance is poor and special welding technique is needed to weld the internal or through diaphragm. Accordingly, We developed a welded built-up square steel tube having a welding lines and a stiffeners at location out of stress concentration. The welded built-up square steel tube occurred a interference with stiffeners at the internal or through diaphragm, therefore researches of a external diaphragm for welded built-up square CFT column connections are needed for the purpose of avoidance of a interfere with stiffeners. In this study we suggest a design formulation for external diaphragm of the welded built-up square CFT external diaphragm connections. Four specimens were manufactured for a experimental test, then we analyzed the behaviors of the specimens.

• Journal of Korean Society of Steel Construction
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• v.20 no.6
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• pp.711-722
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• 2008

Existing tube for concrete filled tubular structure is made through welding of four plates irrespective of tube thickness, so production performance is poor and special welding technique is needed to weld the internal diaphragm and through the diaphragm. Therefore, through manufacturing by cold forming development of beam to column connections that is no welding in position of stress concentration is needed. In this study the proposal of beam to column connections details and to making tube specimens by method of bending steel plates, we want to know the compositeeffect between internal anchor and concrete by processing on stress distribution and internal force evaluation of concrete filled tube beam to column connections with a variable of flange welding existence between column and beam, welding quantity between column and diaphragm, existence of concrete in tube, column with diaphragm and general column.