Author : Ali S. Hammood and Haider Mahdi Lieth

The aim of this work is to investigate the effect of retained austenite on microstructure, mechanical properties, and bending fatigue characteristic of austempering ductile iron with chemical composition 3.75Wt. % C,2.6 Wt. % Si, 0.3 Wt. %Mn, 0.01 Wt. % S,0.04Wt. %P by using artificial neural networks. The experimental procedure for nodular cast iron depends upon the effects of austempering heat treatment on the microstructure, mechanical properties, and fatigue behavior. The heating of the samples in two temperature 875oC, 900oC and transferred directly to the salt bath furnace must contain (50 % NaNO3 and 50 % KNO3) in different temperature and different holding period according to case conditions. Obtained result show that neural network is affective tools in evaluation effects of retained austenite on microstructure, mechanical properties, and bending fatigue characteristic of austempering ductile iron. For nodular cast iron when the austempering temperature is increasing fatigue life is increase because the amount of retained austenite also increased at higher temperature this means improving the properties of ductile cast iron. Best case we have obtained after temperature of austenitizing, 875oC, time of austenitizing 90 min, temperature of austempering 400oC, time of austempering 90min.

Keywords: Austempering , Fatigue Behavior, Retained Austenite.

Article published in International Journal of Current  Engineering  and Technology, Vol.3,No.5(Dec- 2013)