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Residual Stresses in Inertia-Friction-Welded Dissimilar High-Strength Steels

Moat, R. J.; Hughes, D. J.; Steuwer, Axel LU ; Iqbal, N.; Preuss, M.; Bray, S. E. and Rawson, M. (2009) In Metallurgical and Materials Transactions A - Physical Metallurgy and Materials Science 40A(9). p.2098-2108
Abstract
The welding of dissimilar alloys is seen increasingly as a way forward to improve efficiencies in modern aeroengines, because it allows one to tailor varying material property demands across a component. Dissimilar inertia friction welding (IFW) of two high-strength steels, Aermet 100 and S/CMV, has been identified as a possible joint for rotating gas turbine components and the resulting welds are investigated in this article. In order to understand the impact of the welding process and predict the life expectancy of such structures, a detailed understanding of the residual stress fields present in the welded component is needed. By combining energy-dispersive synchrotron X-ray diffraction (EDSXRD) and neutron diffraction, it has been... (More)
The welding of dissimilar alloys is seen increasingly as a way forward to improve efficiencies in modern aeroengines, because it allows one to tailor varying material property demands across a component. Dissimilar inertia friction welding (IFW) of two high-strength steels, Aermet 100 and S/CMV, has been identified as a possible joint for rotating gas turbine components and the resulting welds are investigated in this article. In order to understand the impact of the welding process and predict the life expectancy of such structures, a detailed understanding of the residual stress fields present in the welded component is needed. By combining energy-dispersive synchrotron X-ray diffraction (EDSXRD) and neutron diffraction, it has been possible to map the variations in lattice spacing of the ferritic phase on both sides of two tubular Aermet 100-S/CMV inertia friction welds (as-welded and postweld heat-treated condition) with a wall thickness of 37 mm. Laboratory-based XRD measurements were required to take into account the variation in the strain-free d-spacing across the weld region. It was found that, in the heat-affected zone (HAZ) slightly away from the weld line, residual stress fields showed tensile stresses increasing most dramatically in the hoop direction toward the weld line. Closer to the weld line, in the plastically affected zone, a sharp drop in the residual stresses was observed on both sides, although more dramatically in the S/CMV. In addition to residual stress mapping, synchrotron XRD measurements were carried out to map microstructural changes in thin slices cut from the welds. By studying the diffraction peak asymmetry of the 200-alpha diffraction peak, it was possible to demonstrate that a martensitic phase transformation in the S/CMV is responsible for the significant stress reduction close to the weld line. The postweld heat treatment (PWHT) chosen to avoid any overaging of the Aermet 100 and to temper the S/CMV martensite resulted in little stress relief on the S/CMV side of the weld. (Less)
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author
organization
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type
Contribution to journal
publication status
published
subject
in
Metallurgical and Materials Transactions A - Physical Metallurgy and Materials Science
volume
40A
issue
9
pages
2098 - 2108
publisher
Springer
external identifiers
  • wos:000268982100011
  • scopus:68949170793
ISSN
1073-5623
DOI
10.1007/s11661-009-9915-0
language
English
LU publication?
yes
id
7b9b6642-ca4a-4995-ad7a-f78e181888fe (old id 1477213)
date added to LUP
2009-09-23 12:58:11
date last changed
2017-08-13 03:53:45
@article{7b9b6642-ca4a-4995-ad7a-f78e181888fe,
  abstract     = {The welding of dissimilar alloys is seen increasingly as a way forward to improve efficiencies in modern aeroengines, because it allows one to tailor varying material property demands across a component. Dissimilar inertia friction welding (IFW) of two high-strength steels, Aermet 100 and S/CMV, has been identified as a possible joint for rotating gas turbine components and the resulting welds are investigated in this article. In order to understand the impact of the welding process and predict the life expectancy of such structures, a detailed understanding of the residual stress fields present in the welded component is needed. By combining energy-dispersive synchrotron X-ray diffraction (EDSXRD) and neutron diffraction, it has been possible to map the variations in lattice spacing of the ferritic phase on both sides of two tubular Aermet 100-S/CMV inertia friction welds (as-welded and postweld heat-treated condition) with a wall thickness of 37 mm. Laboratory-based XRD measurements were required to take into account the variation in the strain-free d-spacing across the weld region. It was found that, in the heat-affected zone (HAZ) slightly away from the weld line, residual stress fields showed tensile stresses increasing most dramatically in the hoop direction toward the weld line. Closer to the weld line, in the plastically affected zone, a sharp drop in the residual stresses was observed on both sides, although more dramatically in the S/CMV. In addition to residual stress mapping, synchrotron XRD measurements were carried out to map microstructural changes in thin slices cut from the welds. By studying the diffraction peak asymmetry of the 200-alpha diffraction peak, it was possible to demonstrate that a martensitic phase transformation in the S/CMV is responsible for the significant stress reduction close to the weld line. The postweld heat treatment (PWHT) chosen to avoid any overaging of the Aermet 100 and to temper the S/CMV martensite resulted in little stress relief on the S/CMV side of the weld.},
  author       = {Moat, R. J. and Hughes, D. J. and Steuwer, Axel and Iqbal, N. and Preuss, M. and Bray, S. E. and Rawson, M.},
  issn         = {1073-5623},
  language     = {eng},
  number       = {9},
  pages        = {2098--2108},
  publisher    = {Springer},
  series       = {Metallurgical and Materials Transactions A - Physical Metallurgy and Materials Science},
  title        = {Residual Stresses in Inertia-Friction-Welded Dissimilar High-Strength Steels},
  url          = {http://dx.doi.org/10.1007/s11661-009-9915-0},
  volume       = {40A},
  year         = {2009},
}