The introduction of titanium and boron as inoculating agents of crystal nuclei for the grain refinement of aluminum and its alloys is a well developed casting pratice.However,the grain refining effect fades away while holding the aluminum melt for a long period.The present work has investigated the variation of chemical composition of titanium and boron in the melt during the holding time.It was found that the composition of these two elements decreased with the holding time and the resulting grain size in the casting ws increased.On agitating the melt after prolonged holding time,the compositions of titanium and borom increased to the original values,along with the recovery of the grain refining effect.It indicates that the settling of inoculating elements and crystal nuclei is the primary reason and is responsible for the fading phenomenon of the grain refinement.The agitation brings the settled inoculating elements and crytal nuclei from the bottom melt back into the bulk melt and also recovers the grain refining effect of the melt.
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