Abstract
In this paper, lapped spot welding of Al plates is examined and the influence of experimental conditions on the weldability is discussed. The microstructure and the microhardness in welded part are investigated. The obtained results are as follows : (1) Welding strength is able to be summarized by power density (W) independent of welding conditions. Welding begins at W=300 kW/cm2 and the maximum strength is obtained in the range of W=700-800 kW/cm2. (2) The molten configuration depends upon irradiating conditions regardless of the thickness of two plates. Therefore, the welded area and the welding strength depend upon only the thickness of upper plate. (3) The microstructure of welded part shows the fine cast structure. The welded part has high microhardness and shearing strengh equivalent to cold rolled bulk. After annealing, the welded part does not become soft and the welding strength does not decrease.
