ASSESSMENT OF THE HYDROGEN LEVEL IN 319 ALUMINUM ALLOY MELTS USING THE THERMAL ANALYSIS TECHNIQUE

摘要

One of the major problems associated with cast aluminum components is the formation of porosity. Porosity is associated with a reduction of mechanical properties, loss of pressure tightness and poor surface integrity in cast components. Porosity formation is usually attributed to the following factors: the shrinkage process, a lack of interdendritic feeding during the mushy zone solidification and the evolution of hydrogen bubbles during the solidification process. This paper presents the results of studies aimed at developing a new procedure for on-line assessment of the hydrogen level in 319 aluminum melts using the Aluminum Thermal Analysis System (AlTAS). The results suggest that the level of dissolved hydrogen (as measured by the AlSCAN unit) can be predicted on the basis of cooling curve characteristics, melt temperature and chemistry with a relatively high degree of accuracy (R~2 = 0.82).