Effects of casting parameters on fluidity of cast LM24 aluminum alloy

The thin section castings suffer from such defects as misrun and cold lap due to rapid solidification of molten metal during mould filling. This limitation can be overcome to some extent by controlling the casting design and casting parameters. In this work, effects of section thickness, pouring temperature and mould surface roughness on fluidity of LM24 aluminium alloy were studied. A six cavity sand mould made by CO2 process was used in the experiments. Cavities were consisted of square cross section channels with thicknesses ranging from 2 to 12mm. Thepouring temperatures in the range of 600-645C and sand grain fineness number (GFN) in the range of 60-170 were used. The length of solidified metal in each channel was recorded as a criterion for melt fluidity. The results indicated a nearly linear rising trend for fluidity length against section thickness at a given pouring temperature and surface roughness. The fluidity was slightly increased by reduction of surface roughness but the maximum casting fluidity was achieved at a medium GFN. The fluidity length was highly increased by rising pouring temperature. The contourgraphs of fluidity length versus section thickness and pouring temperature showed the maximum at the uppermost region of both variables. An optimized range of pouring temperature and section thickness for gaining the maximum fluidity length at any sand roughness could be distinguished.

کلیدواژه ها:

Fluidity length ، LM24 alloy ، pouring temperature ، sand roughness ، section thickness