The mechanical properties of nodular cast iron are reviewed. Effects of alloying, heat treatment, and surface rolling techniques are summarized with reference to long life fatigue strength of this material. Mechanical behavior of this cast iron is shown to be more similar to steel than to gray cast iron. Evidence is presented that graphite nodules act as mechanical stress raisers and that fatigue cracks initiate at these sites. The idea that nodular cast iron can be treated as a notched or flawed steel is advanced. It is suggested that a quantitative relationship between nodule size and fatigue resistance be determined.
Download (1 MB)