A comparison of methods used to assess aluminium melt quality

Abstract

This study reviews and compares the techniques such as LIMCA, PoDFA, Prefil, LIAS and RPT that are used to quantify defects in liquid aluminium alloys. in general, it is found that most of the current techniques are not fully satisfactory. Only the Reduced Pressure Test (RPT) appears to give reliable results of the number and size of bifilms (and sometimes, but not infallibly, an indication of hydrogen content). The density (or Density index) is valuable, but requires the supplement of additional quantification from the number and size of bifilms, which are recommended as additional major quality indicators. The use of a new Melt Quality chart is described.