For the smelting of high strength ductile iron, cupola and power frequency furnace are widely used at home and abroad. In general, hot metal desulfurization. At present, most of the hot metal desulfurization methods use porous plug desulfurization method, that is, blowing N2 gas, adding CaC2 or composite desulfurization agent stirring desulfurization. The stability of desulphurization is of great significance for melting molten iron of crankshaft. For example, induction furnace melting can better control the range of alloy composition, stabilize the spheroidization, and easily ensure the quality of molten iron.

Spheroidizing treatment is an important link in the production of high strength ductile iron crankshaft. The morphology of graphite not only affects the strength performance of the crankshaft, but also affects the fatigue strength and impact resistance of the crankshaft. The selection of spheroidizing agent is of great significance to the effect of spheroidizing treatment.

Rare earth has good desulfurization and balance the harmful tendency of trace elements, purification of molten iron and stable production, but magnesium still plays a role in spheroidization. In view of the increase in the level of desulfurization in domestic foundries, the spheroidizing agent tends to be low in rare earths. In addition, a complex spheroidizing agent containing elements such as calcium, barium, bismuth, and antimony may be used according to the needs of the as-cast matrix structure.

For the smelting of high strength ductile iron, cupola and power frequency furnace are widely used at home and abroad. In general, hot metal desulfurization. At present, most of the hot metal desulfurization methods use porous plug desulfurization method, that is, blowing N2 gas, adding CaC2 or composite desulfurization agent stirring desulfurization. The stability of desulphurization is of great significance for melting molten iron of crankshaft. For example, induction furnace melting can better control the range of alloy composition, stabilize the spheroidization, and easily ensure the quality of molten iron.

Spheroidizing treatment is an important link in the production of high strength ductile iron crankshaft. The morphology of graphite not only affects the strength performance of the crankshaft, but also affects the fatigue strength and impact resistance of the crankshaft. The selection of spheroidizing agent is of great significance to the effect of spheroidizing treatment.

Rare earth has good desulfurization and balance the harmful tendency of trace elements, purification of molten iron and stable production, but magnesium still plays a role in spheroidization. In view of the increase in the level of desulfurization in domestic foundries, the spheroidizing agent tends to be low in rare earths. In addition, a complex spheroidizing agent containing elements such as calcium, barium, bismuth, and antimony may be used according to the needs of the as-cast matrix structure.

When spheroidizing, the high-strength ductile iron mainly considers which spheroidizing process is used, the absorption rate, and whether the reaction is stable. Many foreign factories use the punch cover method, which has the advantages of high absorption rate, less smoke and dust, less investment and wide adaptability. Domestic use of flushing spheroidization process, magnesium absorption rate is low (generally 30% to 50%). Sphonization is a newly developed new spheroidization process, which has the advantages of stable reaction and small temperature loss, and is being gradually promoted.

Inoculation treatment is an important process for spheroidization of high-strength ductile iron. At present, China's widespread use of silicon 75% ferrosilicon alloy, foreign ductile iron inoculant widely used ferrosilicon/zirconium, ferrosilicon/manganese/zirconium and calcium barium compound inoculant, in which zirconium can delay the decline time, manganese can reduce the melting point, so that the inoculation uniform. The use of high-efficiency inoculant can effectively increase the graphite core, refine the grain size, and delay the decay time of inoculation. At present, the flow inoculation method is widely used in the United States, which can effectively control the uniformity of the distribution of inoculants in molten iron. The internal inoculation method is often used in combination with other inoculation methods and is a compound enhanced inoculation process. In addition, the newly developed wire feeding inoculation process is an inoculation method that is carried out simultaneously with the wire feeding spheronization.