Method of squeeze forming metal articles

Claim 1

A method of manufacturing a light metal article in a squeeze forming press by squeeze forming molten metal in a mould of the press wherein: a core comprising a non-sintered soluble salt cure, defining a required shape in the squeeze formed article, produced solely by isostatic compaction of a fine grained salt mixture to such a density and surface finish that it retains its integrity under the conditions of sustained temperature and pressure transmitted thereto by the metal during the squeeze forming operation, is located in a first mould part of the press prior to the introduction of molten metal thereto; molten metal is introduced into said first mould part; the mould is closed under pressure by a second mould part of the press to displace the molten metal to fill a die cavity defined between said first and second mould parts and the metal is maintained under pressure whilst solidification thereof takes place; and the mould is then opened, the squeeze formed metal article extracted and the core dissolved therefrom.

Claim 2

A method of manufacturing a light metal article in a squeeze forming press by squeeze forming molten metal in a mould of the press wherein: a core comprising a non-sintered soluble salt cure, defining a required shape in the squeeze formed article, produced solely by isostatic compaction of a fine grained salt mixture to such a density and surface finish that it retains its integrity under the conditions of sustained temperature and pressure transmitted thereto by the metal during the squeeze forming operation, is located in a first mould part of the press prior to the introduction of molten metal thereto; molten metal is introduced into said first mould part; the mould is closed under pressure by a second mould part of the press to displace the molten metal to fill a die cavity defined between said first and second mould parts and the metal is maintained under pressure whilst solidification thereof takes place; and the mould is then opened, the squeeze formed metal article extracted and the core dissolved therefrom.

Claim 5

A method according to any one of claims 1 wherein the salt core is isostatically compacted at a pressure of approximately 30,000 p.s.i. (207 MPa).

Claim 11

A method of manufacturing a light metal piston crown down bowl in a squeeze forming press by squeeze forming molten metal in a mould of the press wherein: a core comprising a non-sintered soluble salt core, defining the shape of the bowl in the piston crown, produced solely by isostatic compaction of a fine grained salt mixture to such a density and surface finish that it retains its integrity under the conditions of sustained temperature and pressure transmitted thereto by the metal during the squeeze forming operation, is located in a fixed bottom mould part of the press prior to the introduction of molten metal thereto; molten metal is introduced into said bottom mould part; the mould is closed under pressure by a top punch of the press to displace the molten metal to fill a die cavity defined between the top punch and said bottom mould part and the metal is maintained under pressure whilst solidification thereof takes place; and the mould is then opened, the squeeze formed metal piston extracted and the core dissolved therefrom.

Claim 12

A method of manufacturing a light metal piston crown down bowl in a squeeze forming press by squeeze forming molten metal in a mould of the press wherein: a core comprising a non-sintered soluble salt core, defining the shape of the bowl in the piston crown, produced solely by isostatic compaction of a fine grained salt mixture to such a density and surface finish that it retains its integrity under the conditions of sustained temperature and pressure transmitted thereto by the metal during the squeeze forming operation, is located in a fixed bottom mould part of the press prior to the introduction of molten metal thereto; molten metal is introduced into said bottom mould part; the mould is closed under pressure by a top punch of the press to displace the molten metal to fill a die cavity defined between the top punch and said bottom mould part and the metal is maintained under pressure whilst solidification thereof takes place; and the mould is then opened, the squeeze formed metal piston extracted and the core dissolved therefrom.

Claim 15

A method of manufacturing a light metal article in a squeeze forming press by squeeze forming molten metal in a mould of the press wherein: a core comprising a non-sintered soluble salt core, defining a required shape in the squeeze formed article, produced solely by isostatic compaction of a mixture of fine grained sodium chloride, a desiccant and an expansion modifying agent to such a density and surface finish that it retains its integrity under the conditions of sustained temperature and pressure transmitted thereto by the metal during the squeeze forming operation, is located in a first mould part of the press prior to the introduction of molten metal thereto; molten metal is introduced into said first mould part; the mould is closed under pressure by a second mould part of the press to displace the molten metal to fill a die cavity defined between said first and second mould parts and the metal is maintained under pressure whilst solidification thereof takes place; and the mould is then opened, the squeeze formed metal article extracted and the core dissolved therefrom.

Claim 16

A method of manufacturing a light metal article in a squeeze forming press by squeeze forming molten metal in a mould of the press wherein: a core comprising a non-sintered soluble salt core, defining a required shape in the squeeze formed article, produced solely by isostatic compaction of a mixture of fine grained sodium chloride, a desiccant and an expansion modifying agent to such a density and surface finish that it retains its integrity under the conditions of sustained temperature and pressure transmitted thereto by the metal during the squeeze forming operation, is located in a first mould part of the press prior to the introduction of molten metal thereto; molten metal is introduced into said first mould part; the mould is closed under pressure by a second mould part of the press to displace the molten metal to fill a die cavity defined between said first and second mould parts and the metal is maintained under pressure whilst solidification thereof takes place; and the mould is then opened, the squeeze formed metal article extracted and the core dissolved therefrom.