ISSUE 2/2011

/// 03
Kantorík, R.; Bolibruchová, D.
Free melt surface monitoring with the help of metal flow simulation in casting mould

The article deals with monitoring of free melt surface during flow in casting mould. Used simulation software was ProCast. New function of this software is “fluid front tracking indicator” which helps monitor the free surface of melt. Units of this indicator are cm2 · s which means that the indicator monitors time during which was free surface in contact with the atmosphere in the cavity of casting mould. Various types of gating systems have been designed. With the help of flow simulation and indicator Junction free melt surface during metal flow was observed in gating system. Experimental material was aluminium alloy AlSi7Mg0.3 (EN AC-42 100) which is used in automotive industry. Aluminium alloys have great oxygen affinity and immediately react with oxygen. Oxide films can form in 0.01 s as fragments in melt. Their thickness can be several nanometers, if in longer contact with air they become thicker. During the metal flow in gating system the entrainment of originated oxide films could occur. Turbulent flow can transport these films into casting cavity. Gating systems were designed for 10 s filling time. Velocity of flow was also monitored because overrunning the critical velocity causes turbulence, which is unacceptable.

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