Development of Austempered Mn-Cr White Cast Iron

The function and selecting principle of major elements of austempered white cast iron are introduced.The effects of Mn,Cr element and the effects of austempering temperature on mechanical properties and abrasive wear resistance of alloyed white cast iron are studied.The abrasive wear resistance of the alloyed white cast iron austempered at different temperature was compared with that of the as-cast alloyed white cast iron,high chromium cast iron and high manganese steel.The results showed that the as-cast white cast iron and multi-phases structure of free-carbide bainite and austenite after austempering are obtained by correctly selecting carbon and silicon content,adding proper manganese content and a small mount of chromium as well as a trace bismuth.Manganese can be used to improve the hardenability and to reduce productive cost.Based on optimum chemical compositions,the austenitic-bainitic alloyed white cast iron by austempering at 325℃ for 2h,with higher hardness and toughness and better abrasive wear resistance can be obtained.This white cast iron is a new economical and promising wear resistant material.