Effects of Heat Treatment on Graphite Morphology and Impact Resistance in Industrial Grey and Ductile Irons
Based on the results previously obtained for cast alloy structural steels, the influence of isothermal holding at heating or cooling on graphite morphology and impact strength in industrial grey and ductile pearlitic irons were investigated. Some novel microstructure features were revealed in the irons after their optimal heat treatment, namely: ferrite matrix formation instead of pearlitic one in both irons; partial or full solving the original networked graphite plate-like inclusions; branched interfaces of originally spheroid graphite inclusions surrounded by probably nano - structured matrix areas etc. The microstructure features revealed were assumed to be responsible for the obtained unprecedent-ed increase of impact strength up to KCU ≈550 kJ/m2 for each iron grade. The phenomena observed were attributed to a number of the known processes development during the proposed heat treatment, but require additional precise investigations in view of their general importance for metallic materials: composites, deposited, 3-D printed, powder sintered etc.
*Corresponding author: Tkachenko Igor* Priazovsky State Technical University, Department of Materials Science, Mariupol, Ukraine.
Published: December 30, 2019
