Method and apparatus for spray casting of alloy ingots

Abstract

This invention provides a method and apparatus to produce metal or alloy ingots using spray casting with the features of easy manufacture of large diameter ingots and simultaneously their uniform microstructure due to followings. Firstly, spray deposition area on the top surface of the ingot can be enlarged by making use of multiple gas atomizers and also by controlling the their positions for the spray deposition. Secondly, at the same time, a mutually opposite-directional rotation between the gas atomizers and the catching plate provides a uniform deposition of sprayed droplets along the circumference-wise direction over the entire top surface of the ingot. In addition, a mutually opposite-directional reciprocation between the gas atomizer and the top surface of the ingot provides an enlargement of deposition area and an evenness of spray deposition along the radial direction on the top surface of the ingot. Additional features of this invention are vastly increased casting speed allowed by simultaneous application of multiple gas atomizers and ability to produce angled ingots by controlling coordinated rotation or reciprocation of the gas atomizers and the catching plate.

1 . A method of forming an ingot of metal or alloy, comprising the steps of: 
 locating a plurality of gas atomizers around a base axis, wherein spray axes of said gas atomizers are angularly spaced from said base axis by between 0 and 90 degrees;    spraying droplets of molten metal or alloy from said gas atomizers;    positioning a catching plate in a path of said sprayed droplets;    forming an ingot agglomerate by continuous deposition of said sprayed droplets on top surface of said catching plate, thereby growing said ingot along said base axis;    rotating said gas atomizers and/or said catching plate about said base axis for the purpose of an even dispersion of said sprayed droplets along a circumference on top surface of said ingot; and    continuously moving said gas atomizers and/or said catching plate along said base axis in order to maintain a uniform distance between each said gas atomizer and the top surface of said ingot.    
     
     
         2 . The method of  claim 1 , wherein said gas atomizers are arranged around said base axis in order that each melt spray spouting from said gas atomizers deposits at an identical radial position on the top surface of said ingot.  
     
     
         3 . The method of  claim 1 , wherein said gas atomizers are arranged around said base axis in order that each melt spray spouting from said gas atomizers deposits at the corresponding different radial positions on the top surface of said ingot.  
     
     
         4 . The method of  claim 1 , wherein said gas atomizers are rotated about said base axis at a uniform angular velocity and said catching plate is not rotated.  
     
     
         5 . The method of  claim 1 , wherein said catching plate is rotated about said base axis at a uniform angular velocity and said gas atomizers are not rotated.  
     
     
         6 . The method of  claim 1 , wherein said gas atomizers are rotated about said base axis at a periodically variable angular velocity and said catching plate is not rotated.  
     
     
         7 . The method of  claim 1 , wherein said catching plate is rotated about said base axis at a periodically variable angular velocity and said gas atomizers are not rotated.  
     
     
         8 . A method according to any of  claims 1  to  7 , including the step of reciprocating said gas atomizers and/or said catching plate along said base axis for the purpose of a to-and-fro motion of said spray droplets along a radial line on the top surface of said ingot.  
     
     
         9 . The method of  claim 8 , wherein said gas atomizers are reciprocated along said base axis with a fixed reciprocating amplitude and said catching plate is not reciprocated.  
     
     
         10 . The method of  claim 8 , wherein said catching plate is reciprocated along said base axis with a fixed reciprocating amplitude and said gas atomizers are not reciprocated.  
     
     
         11 . A method of forming an ingot of metal or alloy, comprising the steps of: 
 spraying droplets of molten metal or alloy from an gas atomizer whose spray axis is angularly spaced from a base axis by between 0 and 90 degrees;    positioning a catching plate in a path of said sprayed droplets;    forming an ingot agglomerate by continuous deposition of said sprayed droplets on top surface of said catching plate, thereby growing said ingot along said base axis;    rotating said gas atomizer and/or said catching plate about said base axis for the purpose of an even dispersion of said sprayed droplets along a circumference on top surface of said ingot; and    providing a continuous motion to said gas atomizer and/or said catching plate along said base axis in order to maintain a periodic variation of a distance between said gas atomizer and the top surface of said ingot.    
     
     
         12 . The method of  claim 11 , wherein said gas atomizer is rotated about said base axis at a uniform angular velocity and said catching plate is not rotated.  
     
     
         13 . The method of  claim 11 , wherein said catching plate is rotated about said base axis at a uniform angular velocity and said gas atomizers is not rotated.  
     
     
         14 . A method according to  claims 11  to  13 , wherein a plurality of gas atomizers located around said base axis are used.  
     
     
         15 . A method of forming an ingot of metal or alloy, comprising the steps of: 
 spraying droplets of molten metal or alloy from an gas atomizer whose spray axis is angularly spaced from a base axis by between 0 and 90 degrees;    positioning a catching plate in a path of said sprayed droplets;    forming an ingot agglomerate by continuous deposition of said sprayed droplets on top surface of said catching plate, thereby growing said ingot along said base axis;    rotating either said gas atomizer or said catching plate about said base axis at a periodically varying angular velocity every quarter turn of said gas atomizer or said catching plate; and    providing a continuous motion to either said gas atomizer or said catching plate along said base axis in order to maintain a periodically varying distance between said gas atomizer and the top surface of said ingot every quarter turn of said gas atomizer or said catching plate.    
     
     
         16 . The method of  claim 15 , wherein two or four gas atomizers located with a mutual symmetry centered on said base axis are used.  
     
     
         17 . An apparatus of forming an ingot of metal or alloy, comprising: 
 a tundish that contains molten metal or alloy;    an gas atomizer, whose spray axis is angularly spaced from said base axis by between 0 and 90 degrees, located below said tundish;    a catching plate positioned in a path of sprayed droplets spouted from said gas atomizer;    means for rotating said catching plate about said base axis;    means for reciprocating said catching plate along said base axis; and    means for providing continuous motion to said catching plate along said base axis.    
     
     
         18 . The apparatus of  claim 17 , wherein a plurality of gas atomizers are located around said base axis.  
     
     
         19 . An apparatus of forming an ingot of metal or alloy, comprising: 
 a tundish that contains molten metal or alloy;    an gas atomizer, whose spray axis is angularly spaced from said base axis by between 0 and 90 degrees, located below said tundish;    a catching plate positioned in a path of sprayed droplets spouted from said gas atomizer;    means for rotating said gas atomizer about said base axis;    means for reciprocating said gas atomizer along said base axis; and    means for providing continuous motion to said catching plate along said base axis.    
     
     
         20 . The apparatus of  claim 19 , wherein a plurality of gas atomizers are located around said base axis.  
     
     
         21 . An apparatus of forming an ingot of metal or alloy, comprising: 
 a tundish that contains molten metal or alloy;    a plurality of gas atomizers located around a base axis below said tundish, wherein spray axes of said gas atomizers are angularly spaced from said base axis by between 0 and 90 degrees;    a catching plate positioned in a path of sprayed droplets spouted from said gas atomizers;    means for rotating said catching plate about said base axis; and    means for providing continuous motion to said catching plate along said base axis.    
     
     
         22 . An apparatus of forming an ingot of metal or alloy, comprising: 
 a tundish that contains molten metal or alloy;    a plurality of gas atomizers located around a base axis below said tundish, wherein spray axes of said gas atomizers are angularly spaced from said base axis by between 0 and 90 degrees;    a catching plate positioned in a path of sprayed droplets spouted from said gas atomizers;    means for rotating said gas atomizer about said base axis; and    means for providing continuous motion to said catching plate along said base axis.