• Title/Summary/Keyword: 저항용접

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Characterization of Primary Dynamic Resistance in Resistance Spot Welding (저항 점 용접의 1차 동저항 특성에 관한 연구)

  • 조용준;이세헌;신현일;배경민
    • Journal of Welding and Joining
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    • v.17 no.2
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    • pp.97-103
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    • 1999

  • The dynamic resistance monitoring in primary circuit is one of the important issues. Because in-process and real time quality assurance of resistance spot weld is needed to increase the product reliability. In this study, new dynamic resistance detecting method is proposed as a practical manner of weld quality assurance using instantaneous current and voltage measured at the primary circuit. and also, various patterns of primary dynamic resistance curve are characterized with the macro photograph and the weldability lobe curve. It is found that the primary dynamic resistance patterns are basically similar to those of the secondary, but there is evident advantage such as no extra devices are needed to obtain the quality information and eventually real time feedback control will be possible.

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The Effect of Weld Line on the Mechanical Strengths and its Elimination Process in the Zr-4 Resistance Upset Welds (지르칼로이-4의 저항업셋용접에서 용접선이 기계적성질에 미치는 영향과 그 소멸과정)

  • Koh, Jin-Hyun;Lee, Jung-Won;Jung, Sung-Hoon
    • Nuclear Engineering and Technology
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    • v.23 no.1
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    • pp.1-11
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    • 1991

  • The objective of this study is to investigate the effect of weld line on the mechanical strengths and the process of weld line elimination in the Zircaloy-4 resistance upset welding for the fabrication of heavy water reactor fuel rods. The weld current and the amount of upset increased linearly with the main heat, in which two relations between them were derived. It was found that the threshold to obtain sound weld was 50% of main heat in terms of weld upset size, mechanical strengths and weld line elimination. The weld microstructure of resistance upset welds of Zircaloy-4 comprsied basketweave, Widmanstatten and martensite respectively by changing the main heats. Dimples on uniaxially fractured surface at weld line in the Zr-4 welds were larger and deeper compared with those on biaxially fractured surface. It was also found that the process of the weld line elimination in the resistance upset weld of Zircaloy-4 could be divided into three stages in terms of the presence of many pores, their shrinkage and elimination, and the shrinkage of the original weld interface with increasing weld currents.

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