Influence of inoculation on the formation of secondary (polygonization) boundaries in cast iron
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High cooling rates cause the formation in uninoculated iron of zones heterogeneous in structure which in character of disposition resemble polygonized boundaries.
Inoculation of cast iron with small additions of elements (formation of compact forms of graphite together with lamellar) leads to formation of polygonized boundaries (coarse secondary grains) and under certain conditions (an increase in cooling rate) cracks are formed at these boundaries.
With an increase in graphite of the compact form in the structure of cast iron the size of the secondary grains in the iron decreases.
In the presence of spheroidal graphite in the structure of the iron the polygonization process is not observed.
KeywordsIron Graphite Cool Rate Cast Iron Compact Form
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