Relationship between matrix-microstructure and mechanical properties of copper alloyed thin wall austempered gray cast iron (TWAGI)

Abstract

In this investigation the characteristics of thin wall (3 mm thickness) castings of copper alloyed gray cast iron have been examined. The samples of the thin wall castings have been austempered isothermally thus the thin wall austempered gray iron (TWAGI) produced. The samples austenitizing at 927 °C (1700 °F), the samples have been austempered at 260 °C (500 °F), 285 °C (545 °F), 310 °C (590 °F), 335 °C (635 °F), 360 °C (680 °F) and 385 °C (725 °F) respectively for 1 h. As a result, these samples developed an ausferrite matrix and excellent mechanical properties. The microstructures of these samples TWAGI have been characterized through optical microscopy, scanning electron microscopy and X-ray diffraction analysis. The mechanical properties may be correlated with the volume fraction of austenite and ferrite and ferrite cell size in the ausferrite microstructure.

Keywords:

• Austempered gray iron (AGI)
• thin-wall castings
• metallographic
• mechanical properties
• ausferrite matrix

Acknowledgments

The authors would like to thank Mr. Sanjeev Aggarwal, Director of Binay Udyog Pvt. Ltd, Howrah for supplying the grey iron castings material. The authors also wise to thank the University Grant Commission, New Delhi, India for their financial support for this work under Rajiv Gandhi National Fellowship (RGNF) scheme.