Method for manufacturing ceramic reinforced piston

A method of casting an article, comprising the steps of:

• providing a mold having a main body with at least one side wall, at least one opening extending through said side wall, a bottom wall for said mold connected thereto to thereby define a mold interior, an upper punch movable from a raised position spaced from said mold to a lowered position abutting said mold to constitute a top wall of said mold, and at least one push ram respectively movably mounted in said at least one opening, said at least one push ram being movable from a retracted position spaced from said mold interior to an outermost position extending into said mold interior;
• placing said at least one push ram in said outermost position;
• during or subsequent to said step of placing said at least one push ram in said outermost position, inserting a quantity of molten metal into said mold interior with said upper punch in said raised position;
• lowering said upper punch to said lowered position and maintaining said upper punch in said lowered position by application of a first pressure on said upper punch;
• applying a second pressure to said at least one push ram to arrest, at an extended position between said outermost and said retracted positions, movement of said at least one push ram from said outermost position toward said retracted position, said movement being caused by fluid pressure exerted on said at least one push ram by the molten metal, said first pressure being greater than said second pressure, and said at least one push ram in its extended position reducing the volume of said mold interior by an amount whereby the molten metal is pressurized within a prescribed pressure range;
• allowing the molten metal to solidify;
• raising said upper punch to said raised position and moving said at least one push ram to said retracted position;
• and
• removing said article from said mold.