Laser-roll welding of a dissimilar metal joint of low carbon steel to aluminium alloy using 2 kW fibre laser

Abstract

Recently, lightening, speed-up and decreasing vibration of the transport vehicles have been discussed for improving of environmental problems. As one solution, the material hybrid concept using aluminum alloys and high strength steels has been proposed. Therefore, new welding processes by which these dissimilar materials can be joined in high reliability and productivity are demanded. Laser roll welding was developed for joining of dissimilar metals by M. Kutsuna, M. Rathod and A. Tsuboi in 2002. Up to now, a CO₂ laser has been used as a heat source. In the present work, laser roll welding of low carbon steel and aluminum alloy using a 2 kW fibre laser was investigated to improve the joint properties due to the effective heating characteristics. Effects of the process parameters were studied. Otherwise, the influences of process parameters on the weldability, the formation of intermetallic compound layer and the mechanical properties have been investigated. As a result, various types of intermetallic compound layer were confirmed at the laser roll welded joint interfaces. When intermetallic compound layer thickness was less than 10 μm, the specimen was a failure in the base metal of low carbon steel in the tensile shear test.

Keywords:

• laser roll welding
• dissimilar metal joint
• low carbon steel
• aluminum alloy
• intermetallic compound ( = 1MC) layer thickness

Acknowledgements

The fibre lasers used in this study were purchased for the researches of Nagoya University, Mie University, Lasax, Chuo Seiki, Horie Metal Industries and Daido Metals (selected by the Ministry of Economy, Trade and Industry as the ‘New regional consortium of research enterprises’) and we would like to express our gratitude to all those involved.