Method for producing nodular cast iron

Abstract

A method for producing nodular cast iron by using a nodulizer and a spheroidizing device, the method including spheroidizing, the spheroidizing including the following steps: a) placing an integrated rare earth magnesium ferrosilicon nodulizer coated with a rectangular steel tube at a preset position inside a spheroidizing ladle, disposing a strut head on the spheroidizing ladle, and fixing the strut head; b) inputting a ferrosilicon inoculant into the spheroidizing ladle; c) inputting melted iron into the spheroidizing ladle for spheroidizing; and d) removing the strut head from the spheroidizing ladle after spheroidizing.

The invention claimed is: 
     
         1 . A method for producing nodular cast iron by using a nodulizer and a spheroidizing device;
 the nodulizer being prepared by providing a rectangular steel tube ( 13 ) comprising a pressure regulating through hole ( 17 ) arranged on a middle part of a side surface thereof; for the rectangular steel tube, the pressure regulating through hole ( 17 ) being arranged on a middle part of an end surface of a relatively small area; injecting an alloy melt of a rare earth magnesium ferrosilicon nodulizer comprising magnesium ≦20%, silicon ≦65%, and Re ≦3% from the pressure regulating through hole ( 17 ) into the rectangular steel tube ( 13 ) to condense and cool; a diameter of the pressure regulating through hole ( 17 ) being 8-14 mm; using a steel plate having a same thickness as a wall of the rectangular steel tube to close a part of an opening of each of two ends of the rectangular steel tube by means of welding for controlling a reaction time and reaction state of the nodulizer;   the spheroidizing device comprising: a strut head ( 1 ), a steering shaft ( 2 ), a mobile location ( 3 ), a pressure lever ( 4 ), a balance steel ( 5 ), a column and a positioning ruler ( 6 ), a first bolt ( 8 ), and a third bolt and a nut thereof ( 12 ); the strut head ( 1 ) being movable and fixable at a required position by using the third bolt and the nut thereof ( 12 ) disposed on the column and the positioning ruler ( 6 ) as an rotational axis of the pressure lever ( 4 ), arranging the steering shaft ( 2 ) on the pressure lever ( 4 ), and connecting the first bolt ( 8 ) of the steering shaft ( 2 ) to the strut head ( 1 ); a bottom surface of the strut head ( 1 ) being flat; a fire-proof material coated on the strut head ( 1 ) being a frame welded by a threaded steel and an iron wire; the column and the positioning ruler ( 6 ) being welded as a whole body; the mobile location ( 3 ) being arranged on an end part of the positioning ruler; the balance steel ( 5 ) being hanged on the other end of the pressure lever ( 4 );   the method comprising spheroidizing, and the spheroidizing comprising the following steps:
 a) placing an integrated rare earth magnesium ferrosilicon nodulizer ( 18 ) coated with the rectangular steel tube at a preset position inside a spheroidizing ladle ( 7 ), disposing the strut head ( 1 ) on the spheroidizing ladle ( 7 ), and fixing the strut head ( 1 ); 
 b) inputting a ferrosilicon inoculant into the spheroidizing ladle ( 7 ); 
 c) inputting melted iron into the spheroidizing ladle ( 7 ) for spheroidizing; and 
 d) removing the strut head ( 1 ) from the spheroidizing ladle ( 7 ) after the spheroidizing. 
   
     
     
         2 . The method of  claim 1 , wherein the rectangular steel tube ( 3 ) is a square steel tube. 
     
     
         3 . The method of  claim 1 , wherein
 the alloy melt of the rare earth magnesium ferrosilicon nodulizer is poured into the rectangular steel tube ( 13 ); and   the alloy melt is produced by a one-step method for smelting ferrosilicon alloy in a submerged arc furnace or by a remelting method in an electric furnace.   
     
     
         4 . The method of  claim 2 , wherein
 the alloy melt of the rare earth magnesium ferrosilicon nodulizer is poured into the square steel tube ( 13 ); and   the alloy melt is produced by a one-step method for smelting ferrosilicon alloy in a submerged arc furnace or by a remelting method in an electric furnace.   
     
     
         5 . The method of  claim 1 , wherein cooling iron is arranged between a combination of the rectangular or square steel tubes being filled with the alloy melt of the nodulizer. 
     
     
         6 . The method of  claim 2 , wherein cooling iron is arranged between a combination of the rectangular or square steel tubes being filled with the alloy melt of the nodulizer. 
     
     
         7 . The method of  claim 1 , wherein the spheroidizing is processed by using an electric motor to drive a lifting device, hanging the strut head ( 1 ) provided with a counterweight iron ( 15 ) on a hook of the lifting device to substitute the means of using the third bolt and the nut thereof ( 12 ) disposed on the column and the positioning ruler ( 6 ) as the rotational axis of the pressure lever ( 4 ), arranging the steering shaft ( 2 ) on the pressure lever ( 4 ), and connecting the first bolt ( 8 ) of the steering shaft ( 2 ) to the strut head ( 1 ). 
     
     
         8 . The method of  claim 2 , wherein after the spheroidizing, an additional nodulizer is supplied by means of using the third bolt and the nut thereof ( 12 ) disposed on the column and the positioning ruler ( 6 ) as the rotational axis of the pressure lever ( 4 ), arranging the steering shaft ( 2 ) on the pressure lever ( 4 ), and connecting the first bolt ( 8 ) of the steering shaft ( 2 ) to the strut head ( 1 ), the additional integrated rare earth magnesium ferrosilicon nodulizer ( 18 ) coated with the rectangular steel tube is bound to the bottom surface of the strut head ( 1 ) by an iron wire and an iron sheet, and is pressed down into the iron melt for supplying a required amount of magnesium. 
     
     
         9 . The method of  claim 7 , wherein after the spheroidizing, an additional nodulizer is supplied by means of using the electric motor to drive the lifting device, hanging the strut head ( 1 ) provided with the counterweight iron ( 15 ) on the hook of the lifting device, the additional integrated rare earth magnesium ferrosilicon nodulizer ( 18 ) coated with the rectangular steel tube is bound to the bottom surface of the strut head ( 1 ) by an iron wire and an iron sheet, and is pressed down into the iron melt for supplying a required amount of effective magnesium element. 
     
     
         10 . The method of  claim 1 , wherein
 a positioning shaft sleeve ( 25 ) is welded on an upper end of an outer side of the spheroidizing ladle ( 7 ) and connected to the strut head ( 1 ); an end of a positioning handle ( 23 ) is provided with a thread, the thread matches with a nut welded on the positioning shaft sleeve ( 25 ); the thread of the end of the positioning handle ( 23 ) passes through the positioning shaft sleeve ( 25 ) and fastens the strut head ( 1 ); and a position of the strut head ( 1 ) in the spheroidizing ladle ( 7 ) is adjusted by the positioning handle ( 23 );   the strut head ( 1 ) is movable and fixable at the required position; the integrated rare earth magnesium ferrosilicon nodulizer ( 18 ) coated with the rectangular steel tube or by the square steel tube is fixed beneath the strut head ( 1 ); and   the bottom surface of the strut head ( 1 ) is flat; the fire-proof material coated on the strut head ( 1 ) is a frame welded by a round steel, a steel bar, and the iron wire.   
     
     
         11 . The method of  claim 1 , wherein
 an integrated rare earth magnesium ferrosilicon alloy ( 21 ) having a content of rare earth ≦33% and coated with a rectangular or square steel tube is arranged inside an integrated magnesium ferrosilicon nodulizer ( 20 );   a direction of an opening of the integrated magnesium ferrosilicon nodulizer ( 20 ) coated with the rectangular or square steel tube is the same as a direction of an opening of the integrated rare earth magnesium ferrosilicon alloy ( 21 ) having the content of rare earth ≦33% and coated with the rectangular or square steel tube;   the integrated rare earth magnesium ferrosilicon alloy ( 21 ) having the content of rare earth ≦33% and coated with the rectangular or square steel tube is bound to a compositely coated rectangular or square steel tube ( 22 ) by welding;   an alloy melt of the integrated magnesium ferrosilicon nodulizer ( 20 ) is injected into the compositely coated rectangular or square steel tube ( 22 ) to condense and cool;   the cooling iron is arranged between the rectangular steel tubes or square steel tubes being filled with the alloy melt of the nodulizer;   the iron melt is input into the spheroidizing ladle ( 7 ) for spheroidizing; and   during a later half of the reaction time, the integrated rare earth magnesium ferrosilicon alloy ( 21 ) having the content of rare earth ≦33% and coated with the rectangular or square steel tube participates in the spheroidizing for supplying a required amount of rare earth.   
     
     
         12 . The method of  claim 7 , wherein
 an integrated rare earth magnesium ferrosilicon alloy ( 21 ) having a content of rare earth ≦33% and coated with a rectangular or square steel tube is arranged inside an integrated magnesium ferrosilicon nodulizer ( 20 );   a direction of an opening of the integrated magnesium ferrosilicon nodulizer ( 20 ) coated with the rectangular or square steel tube is the same as a direction of an opening of the integrated rare earth magnesium ferrosilicon alloy ( 21 ) having the content of rare earth ≦33% and coated with the rectangular or square steel tube;   the integrated rare earth magnesium ferrosilicon alloy ( 21 ) having the content of rare earth ≦33% and coated with the rectangular or square steel tube is bound to a compositely coated rectangular or square steel tube ( 22 ) by welding;   an alloy melt of the integrated magnesium ferrosilicon nodulizer ( 20 ) is injected into the compositely coated rectangular or square steel tube ( 22 ) to condense and cool;   the cooling iron is arranged between the rectangular steel tubes or square steel tubes being filled with the alloy melt of the nodulizer;   the iron melt is input into the spheroidizing ladle ( 7 ) for spheroidizing; and   during a later half of the reaction time, the integrated rare earth magnesium ferrosilicon alloy ( 21 ) having the content of rare earth ≦33% and coated with the rectangular or square steel tube participates in the spheroidizing for supplying a required amount of rare earth.   
     
     
         13 . The method of  claim 10 , wherein
 an integrated rare earth magnesium ferrosilicon alloy ( 21 ) having a content of rare earth ≦33% and coated with a rectangular or square steel tube is arranged inside an integrated magnesium ferrosilicon nodulizer ( 20 );   a direction of an opening of the integrated magnesium ferrosilicon nodulizer ( 20 ) coated with the rectangular or square steel tube is the same as a direction of an opening of the integrated rare earth magnesium ferrosilicon alloy ( 21 ) having the content of rare earth ≦33% and coated with the rectangular or square steel tube;   the integrated rare earth magnesium ferrosilicon alloy ( 21 ) having the content of rare earth ≦33% and coated with the rectangular or square steel tube is bound to a compositely coated rectangular or square steel tube ( 22 ) by welding;   an alloy melt of the integrated magnesium ferrosilicon nodulizer ( 20 ) is injected into the compositely coated rectangular or square steel tube ( 22 ) to condense and cool;   the cooling iron is arranged between the rectangular steel tubes or square steel tubes being filled with the alloy melt of the nodulizer;   the iron melt is input into the spheroidizing ladle ( 7 ) for spheroidizing; and   during a later half of the reaction time, the integrated rare earth magnesium ferrosilicon alloy ( 21 ) having the content of rare earth ≦33% and coated with the rectangular or square steel tube participates in the spheroidizing for supplying a required amount of rare earth.