Effect of Section Thickness on Austemperability of GGG-70 Nodular Cast Iron Crankshafts
Ali Keleş Gönül Coşkun Mehmet Yıldırım
AbstractIn the present study, the effect of section thickness on the austemperability of Cu alloyed GGG-70 (EN-GJS-700-3) nodular cast iron automotive crankshafts have been investigated. Crankshafts were austenized at 950 °C for 2 h and austempered at 350 for 90 and 120 min. Optical microcope equipped with image analyse software was used to perform microstructural investigation and hardness tests were done to determine mechanical properties. It was shown that section thickness had important influence on austemperability. In the thin sections, ausferrite microstructure has been observed, whereas, in the thick sections, pearlite was formed to due to insufficient cooling rate.