Negative Pressure Updraught Pouring Method

Abstract

A negative pressure updraught pouring method is provided, wherein a melting furnace is filled with molten steel and a flat plate with a suction pipe is covered on a top end of the melting furnace with the bottom end of the suction pipe is dipped into the molten steel; a ventilated mold is placed on the flat plate such that a flow path system of the mold is connected with a top end of the suction pipe; and a chamber is covered on the mold and the flat plate, and the air inside the chamber is drawn out to reduce the air pressure inside the chamber and a cavity of the mold, thereby the molten steel inside the melting furnace is sucked into the mold cavity through the suction pipe and the flow path system by the negative pressure formed inside the chamber for forming a cast.

1 . A negative pressure updraught pouring method provided for at least one mold to form at least one cast, in which a mold cavity and a flow path system connected with each other are disposed inside the mold, the method comprising following steps of:
 a. covering a top end of a melting furnace with a flat plate having a suction plate, filling the melting furnace with molten steel, and dipping a bottom end of the suction pipe into the molten steel;   b. placing the mold on the flat plate in order to connect the flow path system of the mold with a top end of the suction pipe, wherein the mold has an air passage connected with the mold cavity, the mold is a sand mold, and the air passage on the mold is a gap between each of sand grains of the sand mold;   c. placing a chamber over the mold and the flat plate, drawing the air inside the chamber out to reduce the air pressure inside the chamber and the mold cavity, sucking the molten steel inside the melting furnace upwardly through the suction pipe in order to flow the molten steel into the mold cavity; and   d. solidifying the molten steel within a gate between the flow path system and the mold cavity, before the molten steel inside the mold cavity is completely solidified relieving the negative air pressure inside the chamber in order to flow the molten steel inside the flow path system back into the melting furnace, and after the molten steel completely flows back into the melting furnace removing the chamber and detaching the mold from the flat plate in order that the molten steel inside the mold continues to cool down.   
     
     
         2 . (canceled) 
     
     
         3 . (canceled) 
     
     
         4 . The negative pressure updraught pouring method as claimed in  claim 1 , wherein the temperature of the molten steel inside the melting furnace is between 1400° C. and 1550° C.