The invention discloses a control method for increasing the number of
graphite nodules by
solid solution strengthening ferrite nodular
cast iron with a thick and large cross section, which comprises the following steps: selecting materials: 50-70 percent of
pig iron and 30-50 percent of
scrap steel;
smelting: adding the materials into an electric furnace for
smelting, wherein the tapping temperature of the molten iron is 1420-1450 DEG C; spheroidizing: adding a spheroidizing agent, adding a covering agent on the spheroidizing agent, and then spheroidizing, wherein the spheroidizing temperatureis 1420-1450 DEG C; inoculating: adding a
silicon-aluminum-
calcium-
barium type inoculant during a primary
inoculation, and respectively adding the inoculant on the surface of the covering agent and the other side of a
ladle dam before tapping, wherein the distribution proportion is 50 percent; adding a trace amount of
alloy Sb along with the flow of the molten iron during
casting, wherein the adding amount of the
alloy Sb is 0.003-0.005% of the total amount of the molten iron, molding,
casting and cooling: ensuring that the
casting opening temperature is controlled to be <= 300 DEG C, and thecasting is obtained by
air cooling after the casting is opened. The control method has the advantages of obtaining higher number of the
graphite nodules, ensuring a metallographic structure and goodconsistency of performance indexes, thereby improving the quality of the castings and prolonging the service life.