Variation of Toughness and Porosity Formation in Weld Metal with Al Content in Self-Shielded Arc Welding Wire

Bang, Kook-soo; Park, Chan; Woong, Kil; Chang, Woong-Seong

Journal of KWJS 2011;29(1):74-79.
Published online March 4, 2011.

셀프실드용접 와이어의 Al 첨가량에 따른 용접금속 인성 및 기공형성 변화

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Variation of Toughness and Porosity Formation in Weld Metal with Al Content in Self-Shielded Arc Welding Wire

Kook-soo Bang, Chan Park, Kil Woong, Woong-Seong Chang

Abstract

Three different welding wires were used to study the effects of Al content on weld metal toughness and porosity formation in self-shielded arc welding. Weld metal microstructure showed that while wire with 1.3% Al content contains coarse δ-ferrite, wires with less than 0.5% Al content showed no such phase. In addition to the microstructural differences, cleanliness in weld metal was also different among wires. It showed that weld metal toughness was influenced by the δ-ferrite formation, cleanliness and Ni addition. Even though wires with less than 0.5% Al content showed higher weld metal toughness, they showed relatively poor workability, forming porosities in weld bead in lower arc voltages.

Key Words: Self-shield arc welding wire, Al content, Weld metal microstructure, Toughness, porosity