A Study on Weld Defect and Their Alternatives during Lap Welding of AZ31B Magnesium Alloy by Pulsed Nd: YAG Laser

Kim, Jong-Do; Lee, Jung-Han; Kim, Young-Sik

Journal of KWJS 2011;29(3):82-88.
Published online July 7, 2011.

Nd:YAG 펄스 레이저를 이용한 AZ31B 마그네슘 합금의 겹치기 용접에서 발생하는 용접결함과 그 대책에 대한 연구

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A Study on Weld Defect and Their Alternatives during Lap Welding of AZ31B Magnesium Alloy by Pulsed Nd: YAG Laser

Jong-Do Kim, Jung-Han Lee, Young-Sik Kim

Abstract

With a tendency for the application of thin magnesium alloy plates in portable electronic equipment such as cell phone and notebook PC, there is a requirement to develop a welding technology for the lap welding of these thin magnesium alloy. This paper presents the single pulsed laser welding of AZ31B magnesium alloy. The effects of fiber types and parameters such as peak power and pulse width on laser weldability were investigated. The results show that weld defects, especially solidification crack, were always generated in the weld. These defects couldn"t be controlled by the simple square pulse, but could be improved through the application of variable pulse. It is because that variable pulse has effect of solidification delay by dropping peak power gradually.

Key Words: AZ31B magnesium alloy, Pulsed Nd:YAG laser, Lap welding, Weld defects, Pulse control