Preparation of heavy-section ductile iron with improved mechanical properties through quenching and tempering

Abstract

In order to prepare heavy-section ductile iron with high strength and excellent elongation, a series of quenching- tempering experiments was conducted. A relationship between quenching-tempering time and temperature and the contents of martensite and pearlite was established by adjusting different quenching mediums and process parameters, and different microstructures in the iron matrix led to different mechanical properties. The content of martensite in the iron matrix reached over 94% after quenching at 880°C or a higher temperature. Further, the pearlite content could reach over 91% after tempering at 570°C or a higher temperature, thus resulting in improved mechanical properties. The investigated ductile iron yielded mechanical properties of a tensile strength of 970 MPa and an elongation of 6% after quenching in water at 880°C and tempering at 570°C. This will provide more possibilities for the application of heavy-section ductile iron parts.