Accurate Evaluation of the Mechanical Properties of Grey Cast Iron

AbstractGrey cast iron has been regarded, in some circles, as being brittle, low in reliability and one where the usual design equations cannot be applied. The reason is usually attributed to the presence of randomly distributed graphite flakes. This presentation discusses, both experimentally and theoretically, the notch strength, bending strength, and the scattering of tensile strength of grey cast iron, and suggests a new approach based on plasticity theory for the accurate evaluation of these characteristics. Experiments showed that grey iron has a very low notch sensitivity in circumferentially notched bars, but that strength decreases in edge-notched plates. At the temperature of liquid nitrogen, notch sensitivity is very high. In ductile iron, strength increases in notched specimens. These results have been interpreted by the stress distribution, taking into account non-elastic stress/strain behaviour, and using a fracture criteria with an over-stressed depth, δ· The δ is a necessary region for fra...