The invention discloses a preparation method of nodular
cast iron for axle housing castings. The nodular
cast iron comprises the following raw materials: 10-30% of
pig iron, 30-60% of
scrap steel and 15-40% of
foundry returns. 1.5%-2.5% of a carburant and 1.5%-2.0% of 75
ferrosilicon; the preparation method comprises the following steps: preparing the following components in percentage by weight: 0.4%-0.8% of electrolytic
copper, 0.1%-0.4% of a
silicon carbide pretreating agent, 0.8%-0.95% of an Mg30-containing spheroidized core-spun
yarn and 0.2%-0.6% of 0.05% to 0.15% of an Ikine 958
stream inoculant; and through the arrangement of the pretreatment step, the metallurgical reaction is more sufficient, the molten iron is pretreated, and preparation can be better made for subsequent spheroidizing treatment. According to the single-wire feeding spheroidizing method, the spheroidizing process and the
inoculation process are separated, the
waiting time between spheroidizing cored wire feeding and
inoculation treatment is saved, the wire feeding time is shortened, and the production cost is reduced. And the spheroidizing
ladle is additionally arranged between the
smelting furnace and the pouring
ladle, so that the reaction is more sufficient, and the production efficiency is improved. The nodular
cast iron prepared by the method is good in comprehensive performance, the preparation cost is reduced, and an axle housing cast by the nodular cast iron is good in mechanical performance and long in service life.