Cast defects such as microshrinkage reduce the for fatigue strength and reliability of ductile cast iron even though full attention is given for production of the test piece, and so HIP (hot isostatic pressing) is applied to FDI (ferritic ductile cast iron) in order to reduce microshrinkage. After that, rotating bending fatigue tests were carried out. HIP did not change the properties of graphite grains such as mean diameter, nodularity and nodule count. However microshrinkage in the HIP-FDI was completely suppressed. The reduction effect of cast defects by HIP treatment was shown by density measurement and the results of close observations of the fracture surface and the crack initiation site. The fatigue strength was improved at the whole region of fatigue life and the fatigue limit was about 1.32 times that of the material subjected to heat treatment with HIP.
|Number of pages||6|
|Journal||Nippon Kikai Gakkai Ronbunshu, A Hen/Transactions of the Japan Society of Mechanical Engineers, Part A|
|Publication status||Published - Jan 1 1996|
All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Mechanics of Materials
- Mechanical Engineering