Effect of degassing treatment on the quality of Al-7Si and A356 melts

In melting aluminum alloys, inclusion particles suspended in melt can be effectively reduced by floatation and/or sedimentation. Nevertheless, few researchers have focused on the effect of degassing bubbles on inclusion particles entrapped in the Al melt and the poured casting as well. The degassed bubbles evolved from a diffuser, floated up and collapsed on free surface of the melt. After explosion, the splashed droplets dropped on surface and then sank into melt following the movement of convection loop induced near the free surface of melt. Consequently, after degassing treatment, Al-7Si melts increased the inclusion particle counts and foggy marks revealing on the section of chilled samples. The A356.2 melts decreased the inclusion particle counts but increased the foggy marks on the poured chilled samples.