Influence of heat treatment on metallographic and mechanical properties of ductile iron

  • 1 Faculty of Mechanical Engineering, University of Slavonski Brod, Croatia


Due to the mechanical properties (toughness, elongation, tensile strength) that characterize ductile iron, its application in foundry technology is becoming more pronounced every day. The chemical composition and heat treatment of ductile iron have a great influence on the required mechanical properties. Given the operating conditions, the main purpose of heat treatment of ductile iron is to change the desired mechanical properties. Since the specific mechanical properties of ductile iron are generally related to the regularity of the mined graphite nodules, the main objective in production is to produce ductile iron with the highest possible percentage of ductility. In the experimental part of the paper, microstructure and hardness tests were carried out on specimens of ductile iron NL 400 and NL 700 before and after heat treatment by soft annealing (ferritization) and improvement. It was found that the type and corresponding parameters of heat treatment significantly affect the microstructure and the achieved hardness values of the ductile iron test specimens.



  1. Sahoo, M., Sahu, S.: Principles of Metal Casting (Third Edition)., U.S.A., McGraw-Hill, 2014., 816 pp.
  2. Holtzer, M., Górny, M., Dańko, R.: Microstructure and Properties of Ductile Iron and Compacted Graphite Iron Castings., Poland, Springer Cham, 2015., 158 pp.
  3. Chaengkham, P., Srichandr, P.: Continuously cast ductile iron: Processing, structures, and properties., Journal of Materials Processing Technology 211 (2011) 8, 1372-1378.
  4. Filetin, T., Kovačiček, F., Indof, J.: Svojstva i primjena materijala., Zagreb, Fakultet strojarstva i brodogradnje, 2002., 302 pp.

Article full text

Download PDF