Development of a white cast iron of fracture toughness 40 MPa√m

Abstract

White cast irons are limited by their brittleness, and improvement of toughness has proved an elusive goal. In this study a variety of strategies have been applied in combination to achieve improved toughness. Eutectic carbide volume fraction is reduced and non-standard heat treatments are applied.The fracture toughness of the experimental low-carbon white cast iron is found to be superior to that of a conventional 20Cr—2Mo—1Cu white iron for most heat-treated conditions. A maximum toughness of 40 MPa√m was achieved in the experimental white iron, using a four hour high-temperature treatment at 1125°C. This value is substantially higher than anything previously reported for a white cast iron, of any carbon content.A field trial of grinding mill liners manufactured in the experimental white iron was carried out and indicated service lives of more than 80% longer than those obtained with the currently used pearlitic steel.