Mould filling observations of aluminium melts in vacuum-sealed sand moulds

• In order to clarify how the ingate system design influences the mould filling behaviour of aluminium melts in vertically parted vacuum-sealed moulds, some direct observation experiments have been made. A detailed study of how the design of each component in the ingate system affects the mould filling behaviour has been made. The effect of different designs on downsprue-runner connections, runners and end-wall of the runners as well as the effect of wall friction was investigated. The mould filling process was studied through a glass wall and recorded by a video camera. Still images from the videotape are presented and evaluated. The direct observation method has been found to be a very powerful way to follow the melt behaviour during mould filling. To ensure a good filling of the downsprue the melt level in the pouring basin has to be above a certain level from the time when the stopper is removed and during the whole filling sequence. A perpendicular connection between the downsprue and the runner gives a larger flow loss than a rounded type. Due to the larger flow loss the perpendicular connection results in an earlier filling of the downsprue. A tapered runner results in almost simultaneous filling of the specimens compared to a runner with no tapering. On the other hand the tapered runner gives a more divergent melt front which increase the free melt surfaces in contact with air. An additional pocket at the end of the runner has a beneficial effect on the mould filling. A sharp angled pocket is better than a more rounded type. Decreasing the wall thickness increases the flow loss due to wall friction, and causes more significant heat losses.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Materialteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Materials Engineering (hsv//eng)

Nyckelord

Ingate system

Mould filling

Runner

Downsprue

Wall thickness

Publikations- och innehållstyp

vet (ämneskategori)

rap (ämneskategori)