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Journal of Failure Analysis and Prevention

, Volume 13, Issue 4, pp 445–450 | Cite as

Cast Iron Casing Cracking Due to Chunky Graphite Formation

  • Jakub Kaczorowski
  • Karol Jozwiak
  • Marco Innocenti
Technical Article---Peer-Reviewed
  • 178 Downloads

Abstract

Quality inspection of heavy turbomachinery casings made of ductile cast iron has revealed anomalies in the form of characteristic relief pattern on roughly machined surfaces. Detailed microstructural observations determined that this anomaly is related to degeneration of cast iron microstructure where undesired chunky graphite was formed instead of evenly dispersed graphite nodules. Mechanical tests showed that this microstructural alteration led to deterioration of mechanical properties, especially plasticity. Regularity was found as this problem affected mainly thick sections of casts, especially where the cooling rate was limited. This article discusses the consequences of chunky graphite formation, detection methods, acceptance criteria, and preventive actions.

Keywords

Chunky graphite Degenerated nodular cast iron LCF cracking Preventive actions 

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Copyright information

© ASM International 2013

Authors and Affiliations

  • Jakub Kaczorowski
    • 1
  • Karol Jozwiak
    • 2
  • Marco Innocenti
    • 3
  1. 1.General Electric Company Polska Sp. z o.o.WarsawPoland
  2. 2.Warsaw Institute of AviationWarsawPoland
  3. 3.General Electric Oil & Gas Nuovo Pignone S.r.l.FlorenceItaly

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