Method for producing mould and core through curing sodium silicate sand for casting by blowing

Abstract

In a method for producing moulds and cores with cold box through curing sodium silicate sand for casting by blowing, a sand mixture for producing moulds and cores is filled into a forming tool by a core shooter or manually and then is shaped, and the operations of blowing, curing and stripping are carried out. Gases are sequentially blown in the order of CO 2 and compressed gas; or gases are sequentially blown in the order of compressed gas-CO 2 -compressed gas.

We claim: 
     
         1 . A method for producing mould and core with cold box through curing sodium silicate sand for casting by blowing, in which a sand mixture for producing mould and core is filled into a forming tool by a core shooter or manually and then is shaped, and the operations of blowing, curing and stripping are carried out; the method is characterized in that gases are sequentially blown in the order of CO 2  and compressed gas; or gases are sequentially blown in the order of compressed gas-CO 2 -compressed gas; the compressed gas is composed of compressed air and/or compressed air and nitrogen treated by dehumidification and having a dew point of lower than 5° C. 
     
     
         2 . The method for producing mould and core with cold box through curing sodium silicate sand for casting by blowing according to  claim 1 , characterized in that the CO 2  is pure CO 2  or a gas mixture containing CO 2 ; wherein the content of CO 2  in the gas mixture containing CO 2  is 40%-99%, and the rest is industrial nitrogen or dry air. 
     
     
         3 . The method for producing mould and core with cold box through curing sodium silicate sand for casting by blowing according to  claim 1 , characterized in that the operation of blowing is to blow CO 2  first and compressed gas second, the gases are blown into the cavity of the forming tool for curing, the pressure for blowing CO 2  is 0.05-0.6 Mpa, and the blowing duration is 3-200 s; the pressure for blowing compressed gas is 0.05-0.7 Mpa, the blowing duration is 10-2400 s, and stripping is carried out after blowing is ended. 
     
     
         4 . The method for producing mould and core with cold box through curing sodium silicate sand for casting by blowing according to  claim 3 , characterized in that the operation of blowing is to blow CO 2  first and compressed gas second, the gases are blown into the cavity of the forming tool for curing, the pressure for blowing CO 2  is 0.05-0.4 Mpa, and the blowing duration is 10-60 s; the pressure for blowing compressed gas is 0.1-0.5 Mpa, the blowing duration is 20-200 s, and stripping is carried out after blowing is ended. 
     
     
         5 . The method for producing mould and core with cold box through curing sodium silicate sand for casting by blowing according to  claim 1 , characterized in that the operation of blowing is to blow compressed gas first into the cavity of the forming tool by a blow plate, the pressure for blowing compressed gas first is 0.01-0.4 Mpa, and the blowing duration is 5-600 s; then CO 2  is blown, the pressure for blowing CO 2  is 0.05-0.6 Mpa, and the blowing duration is 3-200 s; compressed gas is blown again after CO 2  blowing is ended, the blowing pressure is 0.05-0.7 Mpa, the blowing duration is 10-2400 s, and stripping is carried out after blowing is ended. 
     
     
         6 . The method for producing mould and core with cold box through curing sodium silicate sand for casting by blowing according to  claim 5 , characterized in that the operation of blowing is to blow compressed gas first into the cavity of the forming tool by a blow plate, the pressure for blowing compressed gas first is 0.03-0.3 Mpa, and the blowing duration is 5-120 s; then CO 2  is blown, the pressure for blowing CO 2  is 0.05-0.4 Mpa, and the blowing duration is 10-60 s; compressed gas is blown again after CO 2  blowing is ended, the blowing pressure is 0.1-0.5 Mpa, the blowing duration is 20-200 s, and stripping is carried out after blowing is ended. 
     
     
         7 . The method for producing mould and core with cold box through curing sodium silicate sand for casting by blowing according to  claim 1 , characterized in that pulse blowing is adopted during the operation of blowing CO 2 . 
     
     
         8 . The method for producing mould and core through curing sodium silicate sand for casting by blowing according to  claim 1 , characterized in that the sand mixture for producing mould and core is composed of raw materials with the following mass percentages: 1.2%-5.0% of sodium silicate for casting, 0.0%-2.5% of reinforcing agent, and the balance of raw sand. 
     
     
         9 . The method for producing mould and core with cold box through curing sodium silicate sand for casting by blowing according to  claim 1 , characterized in that the sand mixture for producing mould and core is composed of raw materials with the following mass percentages: 1.5%-3.0% of sodium silicate for casting, 0.0%-1.5% of reinforcing agent, and the balance of raw sand. 
     
     
         10 . The method for producing mould and core with cold box through curing sodium silicate sand for casting by blowing according to  claim 8 , characterized in that the sand mixture for producing mould and core is composed of raw materials with the following mass percentages: 1.5%-3.0% of sodium silicate for casting, 0.0%-1.5% of reinforcing agent, and the balance of raw sand.