48 - Normalizing Heat Treatments to Develop Improved Properties in Heavy Section Iron

Abstract:

The combination of strength and ductility has been difficult to achieve in the pearlitic grades of ductile iron when cast in heavy sections. In DIS Research Project 46, mechanical properties were determined in 1-inch and 3-inch Y-blocks. Tensile elongations of 6% were rarely obtained in the 3-inch Y-blocks, when a minimum yield strength of 55 ksi was reached. Normalizing is commonly employed to obtain 80-55-06 properties in heavier sections. The results of experiments with intercritical heat treatment in Project 46 were also found to be effective in raising mechanical properties. A research study was performed to identify ways to achieve a higher combination of strength and ductility in heavy section ductile iron through normalizing heat treatments.