The Waveform Control and Blowhole Generation in the Wave Pulse MIG Welding for Galvanized Steel Sheets

Cho, Sang-Myung; Kim, Ki-Jung; Lee, Byung-Woo

Journal of KWJS 2005;23(1):69-76.
Published online April 29, 2005.

[연구논문] 아연도금강판에 대한 중첩펄스 MIG 용접에서의 파형제어와 기공 발생 특성

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The Waveform Control and Blowhole Generation in the Wave Pulse MIG Welding for Galvanized Steel Sheets

Sang-Myung Cho, Ki-Jung Kim, Byung-Woo Lee

Abstract

Recently, application of arc welding to galvanized carbon steel sheet is on the increasing trend in the fields of automobile and construction industries. In arc welding process, zinc is evaporated in weld pool, even under the appropriate welding condition and produce blowhole and/or pit. Zinc gas cause instability of arc and increase spatter and fume. This research is purposed to minimize the heat-input and the formation of porosities in the welded joint of the galvanized carbon steel sheet using variable polarity AC wave pulse MIG welding system. An appropriate welding condition which showed low spatter and good bead appearance was acquired by applying the AC pulse MIG welding machine to DC duplicated MIG welding with the solid wire. When oxygen gas was added to shield gas of MIG welding for galvanized steel sheet, arc length was increased and arc stability was improved. In the AC duplicated welding, the loss of galvanized layer was decreased as the amount of heat-input was decreased when the EN ratio was increased under the condition that average welding current was evenly set.