Cast-iron casting, method for manufacturing cast-iron casting, and equipment for manufacturing cast-iron casting

Abstract

A cast-iron casting, method for manufacturing a cast-iron casting, and equipment for manufacturing a cast-iron casting, which are capable of performing a plating or enameling treatment without defects on a surface of the cast-iron casting, regardless of its specifications, without decreasing productivity or increasing manufacturing costs. A mold is molded by decompressing molding sand, and a melt is poured into the mold. The inside of the mold is decompressed until the temperature of a casting formed by the melt falls to or below an A1 transformation point. The equipment includes: at least one mold; a frame feed device that moves the mold; at least one fixed suction device that decompresses the inside of the mold when stopped; at least one movable suction device that moves while decompressing the inside of the mold when the mold is moving; and a temperature sensor that measures the product surface temperature of the casting.

1 . A method for manufacturing a cast-iron casting comprising:
 a step for molding a mold by decompressing molding sand;   a step for pouring a melt into the mold; and   a step for decompressing the inside of the mold until the temperature of the casting formed by the melt falls to or below an A 1  transformation point.   
     
     
         2 . The method for manufacturing a cast-iron casting according to  claim 1 , wherein the molding sand does not contain a binding agent. 
     
     
         3 . The method of manufacturing a cast-iron casting according to  claim 1 , wherein the pressure inside of the mold is maintained between −10 kPa to −70 kPa. 
     
     
         4 . The method for manufacturing a cast-iron casting according to  claim 1 , wherein the proportion of grains having a diameter of less than 53 μm in the molding sand that does not contain a binding agent is 10% or less. 
     
     
         5 . Equipment for manufacturing a cast-iron casting that decompresses molding sand and pours a melt into a mold that has been molded to manufacture a cast-iron casting, comprising:
 at least one mold;   a frame feed device that moves the mold; at least one fixed suction device that decompresses the inside of the mold when the mold is stopped; and   at least one movable suction device that moves while decompressing the inside of the mold instead of the fixed suction device when the mold is moving, wherein the mold is repeatedly moved and stopped by the frame feed device until the casting temperature inside of the mold after the melt has been poured falls to or below an A 1  transformation point.   
     
     
         6 . The equipment for manufacturing a cast-iron casting according to  claim 5 , wherein a plurality of the molds is present, the frame feed device simultaneously moves the plurality of the molds, and at least the same number of the fixed suction device and the movable suction device as the number of the molds are provided. 
     
     
         7 . The equipment for manufacturing a cast-iron casting according to  claim 5 , further comprising:
 a temperature sensor that measures the product surface temperature of the casting; and   a control device that controls such that the fixed suction device is separated from the mold and a decompressed state is released when the product surface temperature of the casting has reached or fallen below the A 1  transformation point.   
     
     
         8 . The equipment for manufacturing a cast-iron casting according to  claim 7 , wherein the temperature sensor is inserted inside of the mold so as to contact the thickest area of the casting inside of the mold. 
     
     
         9 . The equipment for manufacturing a cast-iron casting according to  claim 7 , further comprising a warning light that lights due to an instruction of the control device. 
     
     
         10 . A cast-iron casting manufactured by decompressing the inside of a mold until the casting temperature inside of the mold after a melt has been poured falls to or below an A 1  transformation point in a mold-molding method that decompresses molding sand and pours a melt into the mold that has been molded. 
     
     
         11 . The method of manufacturing a cast-iron casting according to  claim 2 , wherein the pressure inside of the mold is maintained between −10 kPa to −70 kPa. 
     
     
         12 . The method for manufacturing a cast-iron casting according to  claim 2 , wherein the proportion of grains having a diameter of less than 53 μm in the molding sand that does not contain a binding agent is 10% or less. 
     
     
         13 . The method for manufacturing a cast-iron casting according to  claim 3 , wherein the proportion of grains having a diameter of less than 53 μm in the molding sand that does not contain a binding agent is 10% or less.