Segregation of Mn, Si, Al, and Oxygen During the Friction Stir Welding of DH36 Steel

M. Almoussawi, A.J. Smith, Masoumeh Faraji, S. Cater

Research output: Contribution to journalArticle

1 Citation (Scopus)
5 Downloads (Pure)

Abstract

This work investigates the role of welding speed
in elemental segregation of Mn, Si, Al, and oxygen during
friction stir welding (FSW) in DH36 steel. The experimental
work undertaken showed that when the speed of the
FSW process exceeds 500 RPM with a traverse speed of
400 mm/min, then elemental segregation of Mn, Si, Al,
and O occurred. The mechanism of this segregation is not
fully understood; additionally, the presence of oxygen
within these segregated elements needs investigation. This
work examines the elemental segregation within DH36
steel by conducting heat treatment experiments on unwelded
samples incrementally in the range of 1200–1500 C
and at cooling rates similar to that in FSW process. The results of heat treatments were compared with samples
welded under two extremes of weld tool speeds, namely
W1 low tool speeds (200 RPM with traverse speed of
100 mm/min) and W2 high tool speeds (550 RPM with
traverse speed of 400 mm/min). The results from the heat
treatment trials showed that segregation commences when
the temperature exceeds 1400 C and Mn, Si, Al, and
oxygen segregation progress occurs at 1450 C and at a
cooling rate associated with acicular ferrite formation. It
was also found that high rotational speeds exceeding
500 RPM caused localized melting at the advancing-trailing
side of the friction stir-welded samples. The study aims to estimate peak temperature limits at which elemental
segregation does not occur and hence prevent their occurrence
in practice by applying the findings to the tool’s
rotational and traverse speed that correspond to the defined
temperature.
Original languageEnglish
Pages (from-to)569-576
JournalMetallography, Microstructure, and Analysis
Volume6
Issue number6
Early online date13 Nov 2017
Publication statusPublished - Dec 2017

Fingerprint

Friction stir welding
Steel
Oxygen
Welding
Heat treatment
Ferrite
Welds
Melting
Friction
Cooling
Temperature

Keywords

  • Friction stir welding
  • DH36 steel
  • Elemental segregation

ASJC Scopus subject areas

  • Materials Science(all)
  • Engineering(all)

Cite this

Segregation of Mn, Si, Al, and Oxygen During the Friction Stir Welding of DH36 Steel. / Almoussawi, M.; Smith, A.J.; Faraji, Masoumeh; Cater, S.

In: Metallography, Microstructure, and Analysis, Vol. 6, No. 6, 12.2017, p. 569-576.

Research output: Contribution to journalArticle

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