Sod, slurry-on-demand, casting method and charge

Abstract

A SOD (slurry-on-demand) casting method and charge is provided for casting a low-solid-fraction, namely 10 to 30% solid-fraction, alloy.

1 . A SOD (slurry-on-demand) casting method for casting a low-solid-fraction, namely 10 to 30% solid-fraction, alloy, comprising heating said alloy to a molten liquid state, cooling and stirring said alloy to nucleate and create a partial solid phase of said low-solid-fraction, and transferring said alloy while in said partial solid phase of said low-solid-fraction to a casting machine. 
   
   
       2 . The method according to  claim 1  wherein said alloy comprises a pair of constituents of different melting points comprising a first constituent of a first melting point, and a second constituent of a second lower melting point, and comprising, during said cooling and stirring step, cooling said alloy below said first melting point but above said second melting point, and then performing said transferring step. 
   
   
       3 . The method according to  claim 2  comprising selecting said first and second melting points close enough to each other such that during said cooling and stirring step, the solidification of said first constituent is limited to said low-solid-fraction until said second constituent begins to solidify, and performing said transferring step when the temperature of said alloy is between said first and second melting points. 
   
   
       4 . The method according to  claim 3  wherein said alloy comprises aluminum as said first constituent and silicon as said second constituent, and wherein the silicon content in said molten state increases from 9% to 12%±1% during said cooling step between said first and second melting temperatures whereby the amount of aluminum is limited to said low-solid-fraction. 
   
   
       5 . The method according to  claim 4  wherein the eutectic composition of said alloy is at 12.6% silicon. 
   
   
       6 . The method according to  claim 2  comprising nucleating and solidifying said first constituent by magnetic stirring and without introducing a foreign object into the molten alloy. 
   
   
       7 . The method according to  claim 6  comprising, after said heating step, transferring said alloy while in said molten liquid state to a vessel, and performing said cooling and magnetic stirring step while said alloy is in said vessel, and then transferring said alloy in said partial solid phase of said low-solid-fraction from said vessel to said casting machine. 
   
   
       8 . A SOD (slurry-on-demand) casting alloy charge having a low-solid-fraction, namely 10 to 30% by weight solid-fraction. 
   
   
       9 . The SOD casting alloy charge according to  claim 8  wherein said 10 to 30% solid-fraction ratio provides a soupy milkshake-like charge, in contrast to an ice cream-like billet provided by a 40 to 60% solid-fraction ratio. 
   
   
       10 . The SOD casting alloy charge according to  claim 8  wherein said alloy comprises a pair of constituents of different melting points comprising a first constituent of a first melting point, and a second constituent of a second lower melting point. 
   
   
       11 . The SOD casting alloy charge according to  claim 10  wherein said alloy is cooled below said first melting point but above said second melting point, and wherein said first and second melting points are close enough to each other such that during said cooling, the solidification of said first constituent is limited to said low-solid-fraction until said second constituent begins to solidify. 
   
   
       12 . The SOD casting alloy charge according to  claim 11  wherein said alloy comprises aluminum as said first constituent and silicon as said second constituent, and wherein the silicon content in a molten state increases from 9% to 12%±1% during said cooling between said first and second melting temperatures whereby the amount of aluminum is limited to said low-solid-fraction. 
   
   
       13 . The SOD casting alloy charge according to  claim 12  wherein the eutectic composition of said alloy is at 12.6% silicon. 
   
   
       14 . The SOD casting alloy charge according to  claim 10  wherein said first constituent is nucleated and solidified by magnetic stirring and without introduction of a foreign object into a molten said alloy. 
   
   
       15 . The SOD casting alloy charge according to  claim 8  wherein said 10 to 30% solid-fraction alloy is a die cast alloy selected from the group consisting of 380, 383, 360, and Mercalloy alloys.