Wear and corrosion resistance of alumina dies for isothermal semi-solid processing of steel

The tool wear of high-purity alumina (Al2O3) dies applied in semi-solid extrusion of steel X210CrW12 under near-isothermal conditions at 1250–1350 °C is investigated. Results show excellent wear resistance of the Al2O3 dies against semi-solid steel and scale under experimental conditions. Minor chemical interaction was observed at the die inlet which, in contrast to the die land, is in contact with scale formed on the billet during pre-heating. This effect is attributed to the appointed billet pre-heating procedure. A tribochemical interaction mechanism between alumina dies and semi-solid steel is presented. This paper contributes to the evaluation of a self-heating ceramic tool concept for steel thixoextrusion introduced previously. Results lead to the conclusion that the targeted benefit of applying corrosion resistant but thermal shock-sensitive ceramics as die materials for the semi-solid processing of steel is achieved.