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Comparison Between Vanadium and Niobium Effects on the Mechanical Properties of Intercritically Heat Treated Microalloyed Cast Steels

  • Morteza Kalantar
  • Hamidreza Najafi
  • M. Reza Afshar
Article
  • 3 Downloads

Abstract

In this study, a comparison between V- and Nb-containing low-carbon microalloyed cast steels has been made in terms of strength and impact energy after intercritical heat treatment (IHT). After austenitizing at 950 °C and quenching in water, the alloys were intercritically heated at 760, 800 or 840 °C followed by quenching and tempering at 620 °C. In comparison with conventional heat treatment, IHT increased the impact energies at the expense of some reduction in the strength due to the dual ferritic/martensitic microstructure. However, the impact energy of the alloy containing only V, especially after intercritical heating at 760 and 800 °C, was higher than that of the Nb-containing samples. The improvement in the impact energy required an optimum amount of coarse carbonitride precipitates. While, the impact fracture surface of the alloy V was composed of dimples indicating ductile fracture, cleavage facets in the fracture surface of Nb-containing samples indicated brittle fracture.

Keywords

Microalloyed cast steel Intercritical heat treatment Nb 

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Copyright information

© The Korean Institute of Metals and Materials 2018

Authors and Affiliations

  1. 1.Department of Materials Engineering, Science and Research BranchIslamic Azad UniversityTehranIran

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