Journal of Failure Analysis and Prevention

, Volume 14, Issue 4, pp 470–477 | Cite as

Metallurgical Analysis on a Cracked Super Duplex Stainless Steel Flange

  • Tie Liu
  • Richard Wu Zhiyong
  • Daqin Xu
  • Aye Aye Aung
Technical Article---Peer-Reviewed

Abstract

A flange-to-pipe weldment in a seawater-intake-return-line suffered from cracking on its flange portion after in service for 4 months. The flange was fabricated from S32750 super duplex stainless steel. The cracked flange was investigated by visual inspection and fractographic examination on the crack surface, metallographic examination, hardness measurement, and chemical composition analysis of the flange-to-pipe weldment. The results of laboratory analysis showed that the flange had cracked in a brittle manner resulting from the presence of large amount of sigma phase in the flange material. Formation of such brittle second phase precipitates in the flange material was due to improper heat treatment.

Keywords

Super duplex stainless steel Sigma phase Brittle cracking SEM/EDX Heat treatment 

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Copyright information

© ASM International 2014

Authors and Affiliations

  • Tie Liu
    • 1
  • Richard Wu Zhiyong
    • 1
  • Daqin Xu
    • 1
  • Aye Aye Aung
    • 1
  1. 1.Det Norske Veritas Pte Ltd - Testing Inspection & CertificationSingaporeSingapore

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