Grey, as the traditional metal material in casting production, has always occupies an important position in . According to statistics, the output of parts accounted for 38% to 73% of total casting production in the world’s top ten casting production country. The production of castings is about 70 million tons in the whole world. The production of iron castings is about 53 million tons, accounting for 75% of the whole production, and the production of castings is about 37 million tons, accounting for 52% of the total castings.
Iron materials have obtained such a broad range of application which has much to do with their good characteristics of casting, machining, abrasion resistance, heat resistance and shock absorption. Besides, the low cost also makes a contribution to the extensive application.
The strength of grey iron castings depends mainly on graphite and its matrix organization. Excellent casting performance is the main characteristic of grey iron castings. When the eutectic degree is close to 1,its casting performance will be the best. But its strength is reduced with the increase of carbon equivalent. For a long time, there are abundant and systematic researches about the solidification process of iron castings, inoculation treatment and the influences on the structures and mechanical properties of grey iron castings by alloying elements. However the composition of carbon equivalent is about 3.8% in most of the study samples. And the researches of high carbon equivalent conditions need to be appropriately increased.