Microstructure, Mechanical Properties, Toughness, Wear Characteristics and Fracture Phenomena of Austenitised and Austempered Low-Alloyed Ductile Iron

摘要

Conventional ductile iron (DI) and austempered ductile iron (ADI) alloys were successfully produced. The alloying elements—Ni, Mo, Cr and Mn were added to get as-cast low-alloyed ductile iron (LADI) followed by austempering heat treatment. Hardness was measured for all investigated alloys. A hardness conversion table was deduced for irons investigated. Highest values of calculated quality index (QI) were for ADI alloys implying higher material performance. Impact energy values were attributed to microstructure and tensile properties. Wear characteristics of selected ADI alloys showed comparable values with LADI. Micro-hardness values were used to identify the micro-constituents and the work-hardened layers. Fracture modes were revealed and fracture surface observations were done by SEM. Due to higher toughness and QI, and cheap price, it is suggested that rolling mills may be produced from ADI, specially heat-treated instead of LADI.