A method for green sand molding

摘要

The object of the present invention is to provide a method for green sand molding that prevents a bad casting by producing a mold that does not have a brittle surface. The method comprises the steps of filling the green sand into a flask while fluidizing the green sand by aeration at a pressure between 0.05 and 0.18 MPa, and squeezing the green sand that has been filled in the flask, wherein a mold is produced so that the friability of the mold is 10 or less. The friability is a value that is calculated by the following steps: putting the mold in a rotating cylindrical sieve that has a diameter of 177.8 mm and USA sieve size No. 8, rotating the cylindrical sieve at 57 rpm for 60 seconds, dividing the weight of the sand that has passed through the sieve by the weight of the sand that has been put into the sieve, and multiplying the quotient by 100.