Influence of Free Ferrite on the Mechanical Properties of High Strength Intercritical Austempered Ductile Iron

Authors

  • Alejandro Daniel Basso INTEMA, Universidad Nacional de Mar del Plata-CONICET, Av. Colón 10850, Mar del Plata, B7606BVZ, Argentina https://orcid.org/0000-0002-6167-4426
  • Martin Caldera INTEMA, Universidad Nacional de Mar del Plata-CONICET, Av. Colón 10850, Mar del Plata, B7606BVZ, Argentina
  • Nicolás Emanuel Tenaglia INTEMA, Universidad Nacional de Mar del Plata-CONICET, Av. Colón 10850, Mar del Plata, B7606BVZ, Argentina
  • Diego Fernandino INTEMA, Universidad Nacional de Mar del Plata-CONICET, Av. Colón 10850, Mar del Plata, B7606BVZ, Argentina
  • Roberto Enrique Boeri INTEMA, Universidad Nacional de Mar del Plata-CONICET, Av. Colón 10850, Mar del Plata, B7606BVZ, Argentina https://orcid.org/0000-0001-7083-579X

DOI:

https://doi.org/10.3221/IGF-ESIS.61.35

Keywords:

Ductile Iron, Free ferrite, Mechanical properties, heat treatments

Abstract

The first stage of this study investigates the precipitation of free ferrite from the austenite on fully austenitized ductile iron. Several sets of samples of low alloy ductile iron are fully austenitized and then cooled down to different temperatures and different times within the intercritical austenite-ferrite-graphite phase field. Based on these results, heat treatment cycles aimed at obtaining microstructures composed of free ferrite and ausferrite are carried out. Tensile, impact and toughness tests are performed to characterize the mechanical properties. The results show that, related to the high strength austempered ductile iron grades, the best combinations of properties were obtained from the mixed structures composed of 5% free ferrite and 95% ausferrite, resulting from the austempering at 280°C. These amounts of free ferrite allow obtaining an increase of the elongation (about 50%) and impact toughness (about 10%) while the tensile strength and fracture toughness decrease by about 1.5 and 15% respectively.  

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Published

19-06-2022

How to Cite

Influence of Free Ferrite on the Mechanical Properties of High Strength Intercritical Austempered Ductile Iron. (2022). Frattura Ed Integrità Strutturale, 16(61), 519-529. https://doi.org/10.3221/IGF-ESIS.61.35