| 摘要 |
<p>The invention provides a process and a machine for casting metal parts in a mould (3, 4) comprising a mould cavity (10, 11) formed by a surrounding wall and internal cores defining said mould cavity (10, 11) with the shape of said cast part, a system of sprues, runners or ingates defining a flow channel (7) through which said molten metal (M) flows to fill said mould cavity (10, 11) from the bottom (16) up; said mould (3, 4) further comprising a riser cavity (8) wherein a certain amount of molten metal is maintained in fluid communication with said mould cavity (10, 11) while said molten metal (M) in said mould cavity (10, 11) solidifies for supplying more molten metal (M) according to the shrinkage effect of solidification of said metal in said mould cavity (10, 11). According to the invention said process comprises two sequencing pouring steps: - a first pouring step wherein a first portion of molten metal (M) is fed to said flow channel (7) to fill said mould cavity (10, 11) and - a second pouring step wherein another portion of molten metal (Μ') is poured directly to the riser cavity (8). By these measures porosity defects are avoided which otherwise could be effected due to the shrinkage of the cast part by the metal solidification.</p> |
