Journal of Welding and Joining

The Korean Welding and Joining Society (대한용접접합학회)
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The Effects of Start Block and Arc Length on Melt Through and Unmelted Zone at Welding Start in High Speed Plasma Arc Welding of Thin Plate

박판 고속 플라즈마 맞대기 용접에서 용접 시작부의 용락과 미용융에 미치는 시작블록과 아크길이의 영향

  • Chu, Yong-Su (Dept. of Materials Processing Eng., Graduate School, Pukyong National Univ.) ;
  • Hong, Seong-Joon (Productivity Research Institute, LG Electronics) ;
  • Jung, Jae-Pil (Dept. of Materials Sci. and Eng., University of Seoul) ;
  • Cho, Sang-Myung (Div. of Advanced Materials Sci. and Eng., Dept. of Materials Processing Eng., Pukyong National Univ.)
  • 추용수 (부경대학교 대학원 소재프로세스공학과) ;
  • 홍성준 (LG전자 생산성연구원) ;
  • 정재필 (서울시립대학교 신소재공학) ;
  • 조상명 (부경대학교 신소재공학부 소재프로세스공학)
  • Published : 2008.04.30
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Abstract

In welding of thin plate, some defects such as melt through and unmelted zone occur easily at welding start, however there is a limited study on those problems. Therefore the effects of start block and arc length on melt through and unmelted zone at start were investigated in this study. When start block height was lower than base metal, there was melt through at start. And when the height was even with base metal, no unmelted zone existed. Unmelted zone was increased as start block height increased from 0mm to 0.5mm. However unmelted zone was not much changed as the height increasing from 0.5mm to 1.0mm. When gap existed between start block and base metal, melt through occurred. However, unmelted zone was increased as the contact force of start block on base metal was increased from 0kgf to 7.5kgf. And when arc length was decreased from 3.8mm to 3.0mm, unmelted zone was decreased. It was concluded that the optimum condition to prevent melt through and to minimize unmelted zone would be with start block height 0.25mm, contact force 3.0kgf, and arc length 3.4mm. This optimum condition was applied to the mass production line and resulted in satisfied outcome.

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References

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