Method for horizontal continuous casting of magnesium slab or magnesium alloy slab and apparatus therefor

Abstract

A molten Mg or Mg alloy is supplied into a mold, which is sheltered from the surroundings, from a pool in a tundish, which is shielded from the surroundings. An Mg slab or Mg alloy slab in the mold is drawn out to the outside from an outlet of the mold. A cooling medium is jetted onto the slab on an outer side of and in a vicinity of the outlet to cool the slab. A sealing gas is sprayed over an entire width of a free surface of the molten Mg or Mg alloy on an inner side of and in the vicinity of the outlet, to seal a portion above the entire width of the free surface of the molten Mg or Mg alloy, whereby preventing oxygen from flowing into the mold from the portion and preventing the cooling medium from running back to the mold side.

1 . A method for horizontal continuous casting of an Mg slab or Mg alloy slab, comprising: supplying a molten Mg or Mg alloy from a pool in a tundish, which is shielded from surroundings, into a mold that communicates with the pool and is shielded from the surroundings; drawing out the Mg slab or Mg alloy slab formed in the mold to an outside from an outlet of the mold; jetting, after the mold is drawn out, a cooling medium onto the Mg slab or Mg alloy slab on an outer side of the mold outlet and in a vicinity of the outlet to cool the Mg slab or Mg alloy slab; and jetting a sealing gas over an entire width of a free surface of the molten Mg or Mg alloy on an inner side of the mold outlet and in the vicinity of the outlet, the gas sealing a portion above the entire width of the free surface of the molten Mg or Mg alloy in the mold to prevent oxygen from flowing into the mold.  
   
   
       2 . The method for horizontal continuous casting of an Mg slab or Mg alloy slab according to  claim 1 , wherein, a surface temperature of the mold is set at a temperature exceeding one of a melting point of Mg and a solidification temperature of an Mg alloy.  
   
   
       3 . The method for horizontal continuous casting of an Mg slab or Mg alloy slab according to  claim 1 , wherein, a surface temperature of the mold is set at a temperature not exceeding one of a melting point of Mg and a solidification temperature of an Mg alloy such that the molten Mg or Mg alloy supplied from the pool in the tundish into the mold forms a thin solidified shell along an inner wall surface of the mold, and unsolidified molten residue is solidified on the solidified shell to form the Mg slab or Mg alloy slab.  
   
   
       4 . The method for horizontal continuous casting of an Mg slab or Mg alloy slab according to  claim 1 , wherein, between the mold outlet and a cooling medium jetting part, a second sealing gas is jetted over the entire width of the Mg slab or Mg alloy slab, which has been drawn out from the outlet of the mold, the second sealing gas sealing the portion above the entire width of the Mg slab or Mg alloy slab.  
   
   
       5 . The method for horizontal continuous casting of an Mg slab or Mg alloy slab according to  claim 1 , wherein when the Mg slab or Mg alloy slab formed in the mold is to be drawn out from the outlet of the mold, a tip end of the molten Mg or molten Mg alloy is made to contact with a dummy member at a start of drawing-out, the Mg slab or Mg alloy slab is drawn out by drawing out the dummy member, and after being drawn out, the Mg slab or Mg alloy slab is drawn out by a drawing device.  
   
   
       6 . The method for horizontal continuous casting of an Mg slab or Mg alloy slab according to  claim 2 , wherein when the Mg slab or Mg alloy slab formed in the mold is to be drawn out from the outlet of the mold, a tip end of the molten Mg or molten Mg alloy is made to contact with a dummy member at a start of drawing-out, the Mg slab or Mg alloy slab is drawn out by drawing out the dummy member, and after being drawn out, the Mg slab or Mg alloy slab is drawn out by a drawing device.  
   
   
       7 . The method for horizontal continuous casting of an Mg slab or Mg alloy slab according to  claim 3 , wherein when the Mg slab or Mg alloy slab formed in the mold is to be drawn out from the outlet of the mold, a tip end of the molten Mg or molten Mg alloy is made to contact with a dummy member at a start of drawing-out, the Mg slab or Mg alloy slab is drawn out by drawing out the dummy member, and after being drawn out, the Mg slab or Mg alloy slab is drawn out by a drawing device.  
   
   
       8 . The method for horizontal continuous casting of an Mg slab or Mg alloy slab according to  claim 4 , wherein when the Mg slab or Mg alloy slab formed in the mold is to be drawn out from the outlet of the mold, a tip end of the molten Mg or molten Mg alloy is made to contact with a dummy member at a start of drawing-out, the Mg slab or Mg alloy slab is drawn out by drawing out the dummy member, and after being drawn out, the Mg slab or Mg alloy slab is drawn out by a drawing device.  
   
   
       9 . The method for horizontal continuous casting of an Mg slab or Mg alloy slab according to  claim 1 , wherein the sealing gas is jetted toward an outlet side of the mold along the free surface of the molten Mg or molten Mg alloy.  
   
   
       10 . The method for horizontal continuous casting of an Mg slab or Mg alloy slab according to  claim 2 , wherein the sealing gas is jetted toward an outlet side of the mold along the free surface of the molten Mg or molten Mg alloy.  
   
   
       11 . The method for horizontal continuous casting of an Mg slab or Mg alloy slab according to  claim 3 , wherein the sealing gas is jetted toward an outlet side of the mold along the free surface of the molten Mg or molten Mg alloy.  
   
   
       12 . The method for horizontal continuous casting of an Mg slab or Mg alloy slab according to  claim 4 , wherein the sealing gas is jetted toward an outlet side of the mold along the free surface of the molten Mg or molten Mg alloy.  
   
   
       13 . The method for horizontal continuous casting of an Mg slab or Mg alloy slab according to  claim 5 , wherein the sealing gas is jetted toward an outlet side of the mold along the free surface of the molten Mg or molten Mg alloy.  
   
   
       14 . The method for horizontal continuous casting of an Mg slab or Mg alloy slab according to  claim 6 , wherein the sealing gas is jetted toward an outlet side of the mold along the free surface of the molten Mg or molten Mg alloy.  
   
   
       15 . The method for horizontal continuous casting of an Mg slab or Mg alloy slab according to  claim 7 , wherein the sealing gas is jetted toward an outlet side of the mold along the free surface of the molten Mg or molten Mg alloy.  
   
   
       16 . The method for horizontal continuous casting of an Mg slab or Mg alloy slab according to  claim 8 , wherein the sealing gas is jetted toward an outlet side of the mold along the free surface of the molten Mg or molten Mg alloy.  
   
   
       17 . The method for horizontal continuous casting of an Mg slab or Mg alloy slab according to  claim 4 , wherein the second sealing gas is jetted toward a cooling medium jetting side along an upper surface of the Mg slab or Mg alloy slab.  
   
   
       18 . An apparatus for horizontal continuous casting of an Mg slab or Mg alloy slab, comprising: a sheltered board that covers an area extending from a portion above a pool in a tundish to a portion above a mold outlet to shield the area from an outside; a cooling medium jetting tool that is provided one of on an outer side of the mold outlet and at an outlet end of the mold and jets a cooling medium onto the Mg slab or Mg alloy slab, which has been drawn out from the outlet, on the outer side of the mold outlet and in a vicinity of the outlet to cool the slab; and a gas jetting tool having a wide width that is provided on an inner side of the mold outlet and jets a sealing gas over an entire width of the free surface of the molten Mg or Mg alloy to seal a portion above the entire width of the free surface of the molten Mg or molten Mg alloy in the mold, 
 wherein the sealing gas jetted from the gas jetting tool seals the portion above the entire width of the free surface of the molten Mg or molten Mg alloy to prevent oxygen from flowing into the mold therefrom.    
   
   
       19 . The apparatus for horizontal continuous casting of an Mg slab or Mg alloy slab according to  claim 18 , further comprising a second gas jetting tool provided between the outlet of the mold and the cooling medium jetting tool, the second gas jetting tool jetting a second sealing gas over the entire width of the Mg slab or Mg alloy slab that has been drawn from the outlet of the mold to seal the portion above the entire width of the Mg slab or Mg alloy slab.  
   
   
       20 . The apparatus for horizontal continuous casting of an Mg slab or Mg alloy slab according to  claim 19 , wherein the second gas jetting tool is provided at an angle at which the second sealing gas is jetted to a cooling medium jetting side along the Mg slab or Mg alloy slab.  
   
   
       21 . The apparatus for horizontal continuous casting of an Mg slab or Mg alloy slab according to  claim 18 , further comprising, on the outer side of the outlet of the mold, a drawing device that draws out the Mg slab or Mg alloy slab.  
   
   
       22 . The apparatus for horizontal continuous casting of an Mg slab or Mg alloy slab according to  claim 18 , wherein the mold comprises a heating element.  
   
   
       23 . The apparatus for horizontal continuous casting of an Mg slab or Mg alloy slab according to  claim 19 , wherein the mold comprises a heating element.  
   
   
       24 . The apparatus for horizontal continuous casting of an Mg slab or Mg alloy slab according to  claim 20 , wherein the mold comprises a heating element.  
   
   
       25 . The apparatus for horizontal continuous casting of an Mg slab or Mg alloy slab according to  claim 21 , wherein the mold comprises a heating element.  
   
   
       26 . The apparatus for horizontal continuous casting of an Mg slab or Mg alloy slab according to  claim 18 , wherein the mold comprises no heating element.  
   
   
       27 . The apparatus for horizontal continuous casting of an Mg slab or Mg alloy slab according to  claim 19 , wherein the mold comprises no heating element.  
   
   
       28 . The apparatus for horizontal continuous casting of an Mg slab or Mg alloy slab according to  claim 20 , wherein the mold comprises no heating element.  
   
   
       29 . The apparatus for horizontal continuous casting of an Mg slab or Mg alloy slab according to  claim 21 , wherein the mold comprises no heating element.  
   
   
       30 . The apparatus for horizontal continuous casting of an Mg slab or Mg alloy slab according to  claim 18 , wherein, in a case where the mold comprises the heating element, the heating element is made switchable between on and off.  
   
   
       31 . The apparatus for horizontal continuous casting of an Mg slab or Mg alloy slab according to  claim 19 , wherein, in a case where the mold comprises the heating element, the heating element is made switchable between on and off.  
   
   
       32 . The apparatus for horizontal continuous casting of an Mg slab or Mg alloy slab according to  claim 20 , wherein, in a case where the mold comprises the heating element, the heating element is made switchable between on and off.  
   
   
       33 . The apparatus for horizontal continuous casting of an Mg slab or Mg alloy slab according to  claim 21 , wherein, in a case where the mold comprises the heating element, the heating element is made switchable between on and off.  
   
   
       34 . The apparatus for horizontal continuous casting of an Mg slab or Mg alloy slab according to  claim 22 , wherein, in a case where the mold comprises the heating element, the heating element is made switchable between on and off.  
   
   
       35 . The apparatus for horizontal continuous casting of an Mg slab or Mg alloy slab according to  claim 23 , wherein, in a case where the mold comprises the heating element, the heating element is made switchable between on and off.  
   
   
       36 . The apparatus for horizontal continuous casting of an Mg slab or Mg alloy slab according to  claim 24 , wherein, in a case where the mold comprises the heating element, the heating element is made switchable between on and off.  
   
   
       37 . The apparatus for horizontal continuous casting of an Mg slab or Mg alloy slab according to  claim 25 , wherein, in a case where the mold comprises the heating element, the heating element is made switchable between on and off.  
   
   
       38 . The apparatus for horizontal continuous casting of an Mg slab or Mg alloy slab according to  claim 26 , wherein, in a case where the mold comprises the heating element, the heating element is made switchable between on and off.  
   
   
       39 . The apparatus for horizontal continuous casting of an Mg slab or Mg alloy slab according to  claim 27 , wherein, in a case where the mold comprises the heating element, the heating element is made switchable between on and off.  
   
   
       40 . The apparatus for horizontal continuous casting of an Mg slab or Mg alloy slab according to  claim 28 , wherein, in a case where the mold comprises the heating element, the heating element is made switchable between on and off.  
   
   
       41 . The apparatus for horizontal continuous casting of an Mg slab or Mg alloy slab according to  claim 29 , wherein, in a case where the mold comprises the heating element, the heating element is made switchable between on and off.  
   
   
       42 . The method according to  claim 1   wherein the cooling medium is a liquid, and the jetting of the sealing gas seals the portion above the entire width of the free surface of the molten Mg or Mg alloy in the mold to prevent any liquid or vapor substance that is generated due to the jetting liquid from returning to the mold.    
   
   
       43 . The method according to  claim 42 , wherein the liquid or vapor substance includes at least one of liquid, droplets, spray and vapor.  
   
   
       44 . The method according to  claim 4 , wherein the cooling medium is a liquid, and the jetting of the sealing gas seals the portion above the entire width of the free surface of the molten Mg or Mg alloy in the mold to prevent any liquid or vapor substance that is generated due to the jetting liquid from returning to the mold.  
   
   
       45 . The method according to  claim 44 , wherein the liquid or vapor substance includes at least one of liquid, droplets, spray and vapor.  
   
   
       46 . The apparatus according to  claim 18 , wherein the cooling medium is a liquid, and the jetting of the sealing gas seals the portion above the entire width of the free surface of the molten Mg or Mg alloy in the mold to prevent any liquid or vapor substance that is generated due to the jetting liquid from returning to the mold.  
   
   
       47 . The apparatus according to  claim 46 , wherein the liquid or vapor substance includes at least one of liquid, droplets, spray and vapor.  
   
   
       48 . The apparatus according to  claim 19 , wherein the cooling medium is a liquid, and the jetting of the sealing gas seals the portion above the entire width of the free surface of the molten Mg or Mg alloy in the mold to prevent any liquid or vapor substance that is generated due to the jetting liquid from returning to the mold.  
   
   
       49 . The apparatus according to  claim 48 , wherein the liquid or vapor substance includes at least one of liquid, droplets, spray and vapor.