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Metallography, Microstructure, and Analysis

, Volume 7, Issue 2, pp 203–208 | Cite as

Determination of the Root Causes for Cracking in a Large-Size Cast Ingot of AISI 4317 Steel Using Microstructural Analysis

  • Abdelhalim Loucif
  • Matthieu Bitterlin
  • Mohammad Jahazi
  • Rami Tremblay
  • Jean-Benoît Morin
  • Louis-Philippe Lapierre-Boire
Technical Article
  • 165 Downloads

Abstract

The objective of the present work is to study the root causes for the cracking and material detachment from the external surface of a 10 metric tons high-strength low-alloy steel ingot after solidification and annealing processes. Failure analysis investigations were conducted on different samples from the cracked areas as well as from non-cracked ones. A combination of optical and electron microscopies, x-ray diffraction, and microhardness techniques were used to study and analyze the nature, morphology, and composition of the different microstructural components in the cracked regions. Thermodynamic software, Thermo-Calc® was used to corroborate and interpret the experimental findings with the existing theories. The results indicated a strong intergranular character of the cracks accompanied by the presence of second-phase particles at prior austenite grain boundaries. Segregation of chromium and manganese was demonstrated through local chemical analysis of the grain boundaries. It was concluded that a rapid cooling rate combined with the weakening of grain boundaries was at the origin of crack initiation.

Keywords

Cast ingot cracking High-strength steel Grain boundaries Cooling rate Carbides Segregation 

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Copyright information

© Springer Science+Business Media, LLC, part of Springer Nature and ASM International 2018

Authors and Affiliations

  • Abdelhalim Loucif
    • 1
  • Matthieu Bitterlin
    • 1
  • Mohammad Jahazi
    • 1
  • Rami Tremblay
    • 2
  • Jean-Benoît Morin
    • 2
  • Louis-Philippe Lapierre-Boire
    • 2
  1. 1.Département de Génie MécaniqueÉcole de technologie supérieureMontréalCanada
  2. 2.Finkl Steel-SorelSaint-Joseph-de-SorelCanada

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