Resistance Spot Welding Characteristics of Mg Alloy Applying Current Waveform Control

Choi, Dong-Soon; Hwang, In-Sung; Kim, Dong-Cheol; Ryu, Jae-Wook; Kang, Moon-Jin

doi:2014.32.2.196

J Weld Join > Volume 32(2); 2014 > Article

Research Paper

Journal of Welding and Joining 2014;32(2):196-201.
DOI: https://doi.org/10.5781/JWJ.2014.32.2.70 Published online May 14, 2014.

Resistance Spot Welding Characteristics of Mg Alloy Applying Current Waveform Control

Dong-Soon Choi^*, In-Sung Hwang^*, Dong-Cheol Kim^*, Jae-Wook Ryu^**, Moon-Jin Kang^*

Correspondence: In-Sung Hwang,
Email: hisman@kitech.re.kr

Abstract

In automotive industry, applying of Mg alloy to autobody has been issued recently as a light metal. But poor resistance spot weldability of Mg alloy is blocking commercialization. So studies on improving resistance spot weldability of Mg alloy is increasing continuously. For reduce loss of heat input during welding, inverter DC power source is considered because of short rise time to target welding current. But rapid rising of welding current can increase temperature rapidly in nugget and oxide film between electrode and base metal, and that causes generating expulsion on low welding current range. In this study, for increase optimum welding current range and prevent generating expulsion, applicate various types of welding current waveform controls during resistance spot welding. For analysis effects of each current waveform control, acceptable welding current regions according to electrode force and welding time is determined and lobe diagram is derived. In result, pre heat is proposed as optimum type of welding current waveform control.

Key Words: Resistance spot welding, Mg alloy, Current waveform control, Weldability