| 摘要 |
In a hot chamber method of pore-free die casting, a gas which reacts with the cast material flushes air from a passage in a nozzle, sprue bushing, and at least a portion of a gooseneck through which the material fills the die cavity, as well as from the die cavity. The reactive gas replaces the air in the passage so that air is not forced into the die cavity by the material when it fills the die cavity. Air in the die cavity would form pores in the cast material. Hot chamber apparatus for practicing the method has a bore communicating with the passage for flushing the passage with the gas. A valve closes the bore when the material fills the die cavity so that the material only enters the die cavity. A heating element heats the valve to prevent the material from solidifying about the valve and thereby interfering with its operation. |
