| 摘要 |
Method for the production of castings, for example motor vehicle wheels, from aluminium, magnesium or similar light metals in low-pressure casting machines consisting essentially of a crucible for keeping the melt hot, a casting mould arranged above the crucible, and a riser which emanates from the casting mould, passes through the top of the crucible and projects into the melt, the metal used up by the production of the casting being made up by the introduction of an extra charge of metal into the casting machine. In this method, a metal ingot (pig) with a mass corresponding essentially to the cast weight is introduced into the gas space above the molten metal level of the casting machine before each casting operation and, after the drawing or ejection of the casting, is introduced into the pool of molten metal in the casting machine. During the solidification stage, the mould is vibrated, preferably at between 15,000 and 25,000 Hz. The charging opening of the crucible is designed as a charging hopper with a height which exceeds the thickness of the pigs only insignificantly and a width such that the pigs can be held next to one another in the hopper with the majority of their length projecting freely above the pool of molten metal. The bottom of the charging hopper is provided with webs which form guide channels for the pigs. A preheating chamber is formed in the top of the casting machine.
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