The 40 Years of Vermicular Graphite Cast Iron in China

In China the research and application of vermicular graphite cast iron as a type of formal engineering material was begun at as same period as other countries but put it into the industrial application was earlier than others.The embedded and comprehensive study of the vermicular graphite cast iron began as early as the 1960-1980's. According to incomplete statistics till now in China more than 600 papers have been publishedregarding researches over ten kinds of production methods and more than 30 types of modifying agents.Formulas were put forward to calculate the critical amount of modifying agents to be added in order to produce the vermicular graphite and mechanisms were brought forward which explains the forming procedure of dross during the treatment.Researches are being perfected on casting properties metallographic structure mechanical-physical properties application and machining performance of the vermicular graphite cast iron as well as the relationships among them.The Mechanical Ministry Standards of the metallographic structure and material for the vermicular graphite cast iron have been formulated.In China many researches have been performed on primary crystallization of vermicular graphite. The heat treatment and alloying improved the performance and enlarge application areas. Hundreds kinds of vermicular graphite castings have been made for vehicles engines mining machines metallurgical parts machinery hydraulic components textile machine parts military engineering as well as the castings that are anti-heat fatigue. The weight of these castings varies from one kilogram to 38 tones. Now the annual output of the vermicular graphite cast iron in China is about 200000 tones. Most of the castings are made by the molten iron from the cupola without preparatory treatment while a few of them are melted in the electric furnacecupola-electric furnace or blast furnace-electric furnace duplex melting.Typical application examples of vermicular graphite iron castings are introduced in this paper.Howeverin China techniques such as quick testing of the molten metal and non-destructive testing of castings' microstructure still need to be improved. Several proposals are put forward in this paper in order to improve our work.In generalChina has not run behind other countries in terms of vermicular graphite cast iron research production and application and in some fields China even takes lead. about 43000 Chinese words 329 references and 5 tables.