The quality improvement of welded joints of die-cast Al alloys using oscillation and current modulation of the electron beam

Abstract

The issues of the difficult weldability of the high-pressure die-cast aluminum alloys - AlSi10Mg(Fe) were studied within the presented paper. The metallographic, CT, and EDX analyses of castings were performed to identify potential origins of weld joint imperfections and deteriorated weldability. A comparative welding test of welding gravitation die-cast alloys was accomplished to review the influence of the melting process on the weld quality. The casting process was analyzed and several mediums were evaluated as potential sources of material contamination. The selected contaminants were intentionally introduced into the weld joints. The research on welding process improvement and the reduction of the susceptibility to the presence of impurities was accomplished in the next step. The aim of the experiments was the use of dynamic deflection of the electron beam and pulse modulation of its power. The influence of different oscillation frequencies, amplitudes, and patterns was examined. The verified technology was developed, based on the achieved results.