Process and apparatus for metal casting
First Claim
1. Apparatus for the production of cast metal components, the apparatus comprising a mould, a casting chamber, metal melting and metal pouring means, a mould chamber adjacent said casting chamber and connected thereto by valve means of sufficient size to allow said mould to pass therethrough, vacuum pump means for producing a reduced pressure in at least said casting chamber, mould heating means, mould moving means to transport said mould between said mould chamber and said casting chamber, and pressurising means connected to said mould chamber for pressurising said mould chamber with a fluid, to a pressure sufficient to achieve at least substantial reduction in shrinkage porosity void formation during solidification of molten metal in the mould chamber wherein said valve means, said mould moving means and said pressurising means are constructed and arranged such that a mould with molten metal therein can be moved from said casting chamber to said mould chamber, said valve means closed and said mould chamber pressurized, all within a time such that said metal is still molten.
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Accused Products
Abstract
Cast components having reduced porosity levels are produced by pouring a molten metal into a mould which is in a first chamber, and withdrawing the filled mould into a second chamber. The second chamber is then isolated from the first chamber with regard to pressure, and the second chamber is then pressurized with a fluid up to a maximum pressure of 7 MPa for at least part of the time required for solidification of the metal in the mould. The pressure is preferably applied within forty seconds from the finish of pouring of the molten metal, and more preferably within twenty seconds. The still molten state of the metal permits the use of a relatively low pressure to reduce the porosity levels.
58 Citations
12 Claims
- 1. Apparatus for the production of cast metal components, the apparatus comprising a mould, a casting chamber, metal melting and metal pouring means, a mould chamber adjacent said casting chamber and connected thereto by valve means of sufficient size to allow said mould to pass therethrough, vacuum pump means for producing a reduced pressure in at least said casting chamber, mould heating means, mould moving means to transport said mould between said mould chamber and said casting chamber, and pressurising means connected to said mould chamber for pressurising said mould chamber with a fluid, to a pressure sufficient to achieve at least substantial reduction in shrinkage porosity void formation during solidification of molten metal in the mould chamber wherein said valve means, said mould moving means and said pressurising means are constructed and arranged such that a mould with molten metal therein can be moved from said casting chamber to said mould chamber, said valve means closed and said mould chamber pressurized, all within a time such that said metal is still molten.
- 7. A process for the production of castings, the process comprising the steps of at least partially melting a metal charge, pouring said metal into a mould which is in a first chamber, withdrawing the filled mould completely into a second chamber while the metal in the mould is still in a molten state, isolating said second chamber from said first chamber with regard to pressure and then pressurising said second chamber with a fluid up to a maximum pressure of 7 MPa such as to preclude shrinkage porosity void formation for at least part of the time required for solidification of the metal in the mould.
Specification