Influence of Austempering Temperatures on the Microstructure and Mechanical Properties of Austempered Ductile Cast Iron
Regita Bendikiene,
Antanas Ciuplys,
Ramunas Cesnavicius,
Audrius Jutas,
Aliaksandr Bahdanovich,
Dzianis Marmysh,
Aleh Nasan,
Liudmila Shemet,
Sergei Sherbakov
Affiliations
Regita Bendikiene
Department of Production Engineering, Faculty of Mechanical Engineering and Design, Kaunas University of Technology, Studentu str. 56, 51424 Kaunas, Lithuania
Antanas Ciuplys
Department of Production Engineering, Faculty of Mechanical Engineering and Design, Kaunas University of Technology, Studentu str. 56, 51424 Kaunas, Lithuania
Ramunas Cesnavicius
Department of Mechanical Engineering, Faculty of Mechanical Engineering and Design, Kaunas University of Technology, Studentu str. 56, 51424 Kaunas, Lithuania
Audrius Jutas
Department of Mechanical Engineering, Faculty of Mechanical Engineering and Design, Kaunas University of Technology, Studentu str. 56, 51424 Kaunas, Lithuania
Aliaksandr Bahdanovich
Department of Theoretical and Applied Mechanics, Faculty of Mechanics and Mathematics, Belarusian State University, Nezavisimosti ave 4, 220030 Minsk, Belarus
Dzianis Marmysh
Department of Theoretical and Applied Mechanics, Faculty of Mechanics and Mathematics, Belarusian State University, Nezavisimosti ave 4, 220030 Minsk, Belarus
Aleh Nasan
Department of Theoretical and Applied Mechanics, Faculty of Mechanics and Mathematics, Belarusian State University, Nezavisimosti ave 4, 220030 Minsk, Belarus
Liudmila Shemet
Department of Theoretical and Applied Mechanics, Faculty of Mechanics and Mathematics, Belarusian State University, Nezavisimosti ave 4, 220030 Minsk, Belarus
Sergei Sherbakov
Department of Theoretical and Applied Mechanics, Faculty of Mechanics and Mathematics, Belarusian State University, Nezavisimosti ave 4, 220030 Minsk, Belarus
The influence of the austempering temperatures on the microstructure and mechanical properties of austempered ductile cast iron (ADI) was investigated. ADI is nodular graphite cast iron, which owing to higher strength and elongation, exceeds mechanical properties of conventional spheroidal graphite cast iron. Such a combination of properties is achieved by the heat treatment through austenitization, followed by austempering at different temperatures. The austenitization conditions were the same for all the samples: temperature 890 °C, duration 30 min, and quenching in a salt bath. The main focus of this research was on the influence of the austempering temperatures (270 °C, 300 °C, and 330 °C) on the microstructure evolution, elongation, toughness, and fatigue resistance of ADI modified by certain amounts of Ni, Cu, and Mo. The Vickers and Rockwell hardness decreased from 535.7 to 405.3 HV/1 (55.7 to 44.5 HRC) as the austempering temperature increased. Optical images showed the formation of graphite nodules and a matrix composed of ausferrite; the presence of these phases was confirmed by an XRD diffraction pattern. A fracture surface analysis revealed several types of the mechanisms: cleavage ductile, transgranular, and ductile dimple fracture. The stress-controlled mechanical fatigue experiments revealed that a 330 °C austempering temperature ensures the highest fatigue life of ADI.
