Development history of ductile iron in other countries

- Oct 30, 2019-

France's Reaumur made white heart malleable cast iron in 1722. Later, in the United States, Seth Boyden invented the black heart malleable cast iron in 1826.

In the 1920s. Since the research on the main components such as carbon and silicon in cast iron and the addition of other alloying elements, the melting method, and the inoculation effect have progressed, so-called high-grade cast iron has appeared. As a result, the material has been considerably improved and has expanded the range of applications to some extent. However, due to the fundamental shortcomings of low toughness, it has not been possible to rapidly expand its range of applications.

In 1947, Morrogh of the smoke discovered cast iron with spheroidal graphite in the as-cast state.

In 1948, spheroidal graphite cast iron was prepared by adding Ce to high carbon, low sulfur and low phosphorus gray cast iron and keeping the residual amount above 0.02%. At about the same time, the same spheroidal graphite cast iron was obtained by adding the Mg to the cast iron and keeping the residual amount above 0.04% by the International Nickel Corporation (INCO) Gagnebin.

During the Second World War, the lack of chromium resources necessary for the production of wear-resistant martensitic white cast iron, the study of Cr's alternative elements has become a top priority. Thus, various metals and transition metals that are chemically bonded to carbon have been systematically investigated for their ability to form carbides, including magnesium. In order to alleviate the intense splashing during magnesium addition, Cu80-Mg20 alloy and Ni80-M920 alloy have been used. The results show that magnesium not only has a good effect as a substitute element for chromium, but also finds that when magnesium has a certain residual amount in molten iron, it has a significant desulfurization effect. Based on these new findings, the role of magnesium in grey cast iron was also studied following white cast iron. In the gray cast iron containing C 3.5%, Si2.25% and Ni 2%, 0.5% of Mg is added, and the tensile strength far exceeds the original expectation (about 13kgf/mm2 for ordinary gray cast iron), up to 78kgf/mm2. .


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