Influence of duplex ferritic-austenitic matrix on two body abrasive wear behaviour of high chromium white cast iron

Abstract

Wear resistance of white cast iron is known to be sacrificed when it is attempted to enhance the impact toughness. In the present study, it is shown that a suitably engineered microstructure can retain/enhance the wear resistance between 2.5 and 3.5 times even when impact energy value is increased from 4 J/cm2 to 13 J/cm2. A novel microstructure is designed based on DICTRA®™ simulation and is validated after casting and subsequent cyclic annealing. The novelty of this microstructure is the presence of duplex ferritic-austenitic matrix and partially spherodized M7C3 carbides. The wear behaviour of the newly developed grades is compared with standard class-III high chromium white cast iron. The microstructure of the investigated alloys, the role of micro-constituents on the wear mechanism is extensively studied through scanning electron microscopic examination. The abrasive wear resisting mechanisms of the newly developed alloy are ascertained to be resistance to plastic flow leading to formation of humps and the formation of surface fatigue cracks.