Device and method for preparing large-sized high-quality aluminium alloy ingot

Abstract

Provided is a device for preparing a large-sized high-quality aluminium alloy ingot, which is mainly composed of a uniform cooler, a hot top, an oil-gas lubrication mold, an induction coil and a dummy ingot, wherein the hot top is arranged above the oil-gas lubrication mold, the induction coil is arranged outside the oil-gas lubrication mold, the uniform cooler is arranged inside the oil-gas lubrication mold, and the dummy ingot is arranged below the oil-gas lubrication mold. Further provided is a method for preparing a large-sized high-quality aluminium alloy ingot. The device combines a partitioned gas supply mold with the uniform cooler and an electromagnetic stirrer, and the effective coupling of the three achieves forced and uniform solidification forming of a melt under gas pressure contact conditions, such that a stable and continuous gas film is formed between the melt and the mold. The ingot has a smooth surface, and a fine and uniform internal structure.

1 . A device for preparing a large-sized high-quality aluminium alloy ingot, comprising:
 a uniform cooler;   a hot top;   an oil-gas lubrication mold;   an induction coil; and   a dummy ingot,   wherein the hot top is arranged above the oil-gas lubrication mold, the induction coil is arranged outside the oil-gas lubrication mold, the uniform cooler is arranged inside the oil-gas lubrication mold, and the dummy ingot is arranged below the oil-gas lubrication mold.   
     
     
         2 . The device for preparing a large-sized high-quality aluminium alloy ingot according to  claim 1 , wherein the oil-gas lubrication mold comprises a mold body and a graphite ring mounted above the mold body, wherein the graphite ring is provided with a gas groove and an oil groove on its outer wall, and wherein the oil groove is separated from the gas groove, and is arranged on an upper portion thereof. 
     
     
         3 . The device for preparing a large-sized high-quality aluminium alloy ingot according to  claim 2 , wherein the gas groove is divided into 3-20 sections for independent gas supply and control. 
     
     
         4 . The device for preparing a large-sized high-quality aluminium alloy ingot according to  claim 3 , wherein each section of the gas groove has a length of 100-500 mm. 
     
     
         5 . The device for preparing a large-sized high-quality aluminium alloy ingot according to  claim 2 , wherein the graphite ring is made of porous graphite. 
     
     
         6 . The device for preparing a large-sized high-quality aluminium alloy ingot according to  claim 2 , wherein the mold body is provided with upper and lower rows of water spraying holes, and wherein the upper row of water spraying holes forms an angle of 15-30 degrees with respect to a wall of the mold, and has a diameter of 1-5 mm; while the lower row of water spraying holes forms an angle of 0-25 degrees with respect to the wall of the mold, and has a diameter of 2-8 mm. 
     
     
         7 . The device for preparing a large-sized high-quality aluminium alloy ingot according to  claim 6 , wherein water volumes of the upper and lower rows of water spraying holes are independently controlled, and the diameter of the upper row of water spraying holes is smaller than or equal to that of the lower row of water spraying holes. 
     
     
         8 . The device for preparing a large-sized high-quality aluminium alloy ingot according to  claim 1 , wherein a magnet yoke of the induction coil is of a telescopic design, and is retractable in a range of 0-100 mm, and wherein the induction coil generates an electromagnetic field which is guided into a melt inside the mold via the magnet yoke. 
     
     
         9 . The device for preparing a large-sized high-quality aluminium alloy ingot according to  claim 8 , wherein the induction coil generates a rotating electromagnetic field, a traveling wave electromagnetic field or a compound electromagnetic field. 
     
     
         10 . The device for preparing a large-sized high-quality aluminium alloy ingot according to  claim 1 , wherein an upper portion of the uniform cooler is a heat insulation end, and a lower portion is a cooling end, wherein the heat insulation end is provided with a stirring blade. 
     
     
         11 . The device for preparing a large-sized high-quality aluminium alloy ingot according to  claim 10 , wherein the heat insulation end is of a cylindrical shape, and is made of high temperature-resistant heat insulation ceramic material. 
     
     
         12 . The device for preparing a large-sized high-quality aluminium alloy ingot according to  claim 11 , wherein the heat insulation end has an outer diameter of 100-800 mm. 
     
     
         13 . The device for preparing a large-sized high-quality aluminium alloy ingot according to  claim 10 , wherein the cooling end is made of thermally conductive material. 
     
     
         14 . The device for preparing a large-sized high-quality aluminium alloy ingot according to  claim 13 , wherein the cooling end is of a spiral shape, and is made of graphite, copper, molybdenum, titanium or composite materials thereof. 
     
     
         15 . The device for preparing a large-sized high-quality aluminium alloy ingot according to  claim 10 , wherein the stirring blade is made of high temperature-resistant material, and is arranged to be 0-8 in number. 
     
     
         16 . The device for preparing a large-sized high-quality aluminium alloy ingot according to  claim 15 , wherein the stirring blade is made of copper, molybdenum, titanium, ceramic or composite materials thereof, and has a width of 10-100 mm and a thickness of 2-8 mm. 
     
     
         17 . The device for preparing a large-sized high-quality aluminium alloy ingot according to  claim 1 , wherein the uniform cooler is one or more in number, which is arranged to a height where the mold is located, and has a rotational speed of 0-300 r/min. 
     
     
         18 . The device for preparing a large-sized high-quality aluminium alloy ingot according to  claim 17 , wherein a cooling medium employed by the uniform cooler is air, nitrogen, water or oil, and the flow of the cooling medium is 0-2000 L/min. 
     
     
         19 . A method for preparing a large-sized high-quality aluminium alloy ingot, the method comprising the steps of:
 pouring a melt that has been refined and stabilized to be 80-100 degrees Celsius higher than the liquidus temperature into a hot top during the semi-continuous casting operation;   introducing air and lubricating oil into a gas groove and an oil groove arranged on an outer wall of a graphite ring;   controlling flows of upper and lower water spraying holes;   an alloy melt reaches an upper portion of a dummy ingot through the hot top and a mold, and a liquid surface of the melt is elevated;   after the continuous casting operation is initiated, the dummy ingot descends slowly, and increasing a flow of cooling water slowly; and   after the casting process is stabilized, applying uniform cooling and electromagnetic applied to obtain a large-sized high-quality aluminium alloy ingot in the end.   
     
     
         20 . The method for preparing a large-sized high-quality aluminium alloy ingot according to  claim 19 , wherein the flow of air in the gas groove is 500-5000 mL/min, while the oil groove supplies oil in a pulsed manner, and has an oil supplying capacity of 60-100/s. 
     
     
         21 . The method for preparing a large-sized high-quality aluminium alloy ingot according to  claim 19 , wherein the flow of the upper row of water spraying holes is 1-50 L/min, while that of the lower row of water spraying holes is 20-100 L/min. 
     
     
         22 . The method for preparing a large-sized high-quality aluminium alloy ingot according to  claim 19 , wherein the speed of casting is 20-100 mm/min during the continuous casting operation. 
     
     
         23 . The method for preparing a large-sized high-quality aluminium alloy ingot according to  claim 19 , wherein the cooling intensity of the uniform cooling is 500-5000 W/(m 2 ·k). 
     
     
         24 . The method for preparing a large-sized high-quality aluminium alloy ingot according to  claim 19 , wherein the shearing rate of the electromagnetic stirring is 10-2000 s −1 .