Use of magnetic barkhausen noise (MBN) to follow up the formation of sigma phase in Saf2205 (UNS S31803) duplex stainless steel

Edgar Apaza Huallpa, Eduardo Franco De Monlevade, Julio Capó Sánchez, Manuel Alberteris Campos, Linilson Padovese, Hélio Goldenstein

Research output: Contribution to journalArticlepeer-review

5 Scopus citations

Abstract

Duplex stainless steels have a structure normally composed of austenite and ferrite in approximately equal proportions. In order to attain control of its fabrication processes and performance, it is important to understand its microstructural evolution, due to the formation of intermetallic phases such as sigma (σ) and chi (χ), which may cause a severe deterioration of mechanical properties. In the present study, the evolution of sigma phase during heat treatments at temperatures in which intermetallic phases can be formed (800°C-900°C) was studied using magnetic analyses on a SAF2205 (DIN 1.4462/UNS S31803) steel. A significant reduction of the intensity of Magnetic Barkhausen Noise (MBN) was observed with the increase of heat treatment time, indicating a decrease in the quantity of ferromagnetic phases. For 24-hour-long treatments, the Barkhausen Noise signal is almost completely enclosed by the background noise, indicating the existence of a very small volume fraction of ferrite. If proper calibration samples are to be produced, this technique may be a viable method for non-destructive evaluation of field components working under thermal conditions that may cause the formation of intermetallic phases.

Original languageEnglish
Pages (from-to)1008-1016
Number of pages9
JournalMaterials Research
Volume19
Issue number5
DOIs
StatePublished - 1 Sep 2016

Keywords

  • Duplex stainless steels
  • Feritscope
  • Magnetic Barkhausen noise (MBN)
  • Non-destructive testing
  • Sigma phase

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