• Title/Summary/Keyword: MIAB Welding

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A Study on an Electro-Magnetic System far Arc Rotating in MIAB Welding (MIAB용접에서 아크 회전을 위한 전자기 시스템에 관한 연구)

  • 최동혁;김재웅
    • Journal of Welding and Joining
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    • v.19 no.4
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    • pp.391-398
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    • 2001
  • MIAB welding method uses a rotating arc as its heat source and is known to be efficient in pipe butt welding. The arc is rotated around the weld line by the electro-magnetic force resulting from the interaction of arc current and magnetic field. This paper is concerned with the experiment of initial stage for process control, monitoring for weld quality, and the design of coil system which is efficient of flux generation and concentration. A coil system for the generation of magnetic flux was designed and constructed. Magnetic flux density and arc rotating behavior are important factors in MIAB welding, so the relations between these factors and process parameters were investigated. Various experiments were performed for the steel pipes(48.1mm O.D and 2.0mm thickness). The magnetic flux density is increased by increasing exciting current and decreasing gap size. The maximum of arc rotating frequency is affected by exciting current and gap size. However, the variations of arc rotating frequency during welding and then the melting process are mainly influenced by welding current. Thus, it is considered that the results of this study can be used as important data on the monitoring for weld quality and the design of efficient coil system.

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A Study on the Numerical Analysis of Magnetic Flux Density by a Solenoid for MIAB Welding (MIAB용접에서 코일에 의한 자속밀도 분포의 수치적 해석에 관한 연구)

  • Choe, Dong-Hyeok;Kim, Jae-Ung
    • Journal of the Korean Society for Precision Engineering
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    • v.18 no.12
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    • pp.73-81
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    • 2001
  • The MIAB welding uses a rotating arc as its heat source and is known as an efficient method fur pipe butt welding. The arc is rotated around the weld line by the electro-magnetic force resulting from the interaction of arc current and magnetic field. The electro-magnetic force is affected by magnetic flux density, arc current, and arc length. Especially, the magnetic flux density is an important factor on arc rotation and weld quality. This paper presents a 2D finite element model for the analysis of magnetic flux density in the actual welding conditions. The magnetic flux density is mainly dependent on gap between two pipes, the position of coil from gap center, exciting current, and relative permeability. Thus, the relations between magnetic flux density and main factors were investigated through experiment and analysis. Experiments were performed for the steel pipes(48.1mm O.D and 2.0mm thickness). The analysis results of magnetic flux density reveal that it increases with increasing exciting current, increasing relative permeability, decreasing distance from gap center to coil, and decreasing gap size. It is considered that the results of this study can be used as important data on the design of coil system and MIAB welding system.

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Numerical Analysis of Magnetic Flux Density Distribution by an Openable Magnetic Flux Generator for MIAB Welding (MIVB 용접용 개폐형 자속발생기에 의한 자원밀도분포의 수치해석)

  • Ku Jin-Mo;Kim Jae-Woong
    • Journal of Welding and Joining
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    • v.22 no.6
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    • pp.50-56
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    • 2004
  • MlAB(magnetically impelled arc butt) welding is a sort of pressure welding method by melting two pipe sections with high speed rotating arc and upsetting two pipes in the axial direction. The electro-magnetic force, the driving force of the arc rotation, is generated by interaction of arc current and magnetic field induced from the magnetic flux generator in the welding system. In this study, an openable coil system for the generation of magnetic flux and a 3-dimensional numerical model for analyzing the electro-magnetic field were proposed. Through the fundamental numerical analyses, a magnetic concentrator was adopted for smoothing the magnetic flux density distribution in the circumferential direction. And then a series of numerical analysis were performed for investigating the effect of system parameters on the magnetic flux density distribution in the interested welding area.. Numerical quantitative analyses showed that magnetic flux density distribution generated from the proposed coil system is mainly dependent on the exciting current in the coil and the position of coil or concentrator from the pipe outer surface. And the gap between pipe ends and arc current are also considered as important factors on arc rotating behavior.