Development of aluminum alloy/galvanized steel joining method using refill friction stir spot welding

Abstract

Friction stir spot welding (FSSW) is one of the solid-state welding method and dissimilar material joining by FSSW has been investigated. However, a removable coating is required to form a clean surface on the lower plate in conventional FSSW method. Therefore, we have developed a new dissimilar material joining method – scrubbing refill FSSW (Sc-RFSSW) – and Sc-RFSSW provides higher joint strength than conventional FSSW methods in joining the aluminum alloy and non–coated mild steel. In this study, the mechanical properties and metallurgical joining interface of an aluminum alloy and a hot-dip galvanized (GI) coated steel joint by Sc-RFSSW were investigated. In addition, a new tool tip shape was examined to improve the interfacial cleaning effect.

Keywords:

• Dissimilar metal joining
• friction stir spot welding
• refill friction stir spot welding
• joint strength
• galvanized steel

Acknowledgments

The joint test specimens in this study were provided by the Robot Division of Kawasaki Heavy Industries, Ltd. We hereby express our gratitude.

Additional information

Funding

The evaluation and analysis of the joints in this study were conducted under contract with the New Energy and Industrial Technology Development Organization (NEDO) [No. P14014].