Residual stress control of multipass welds using low transformation temperature fillers

ABSTRACT

Low transformation temperature (LTT) weld fillers can be used to replace tensile weld residual stresses with compressive ones and reduce the distortion of single-pass welds in austenitic plates. By contrast, weld fillers in multipass welds experience a number of thermal excursions, meaning that the benefit of the smart LTT fillers may not be realised. Here, neutron diffraction and the contour method are used to measure the residual stress in an eight pass groove weld of a 304 L stainless steel plate using the experimental LTT filler Camalloy 4. Our measurements show that the stress mitigating the effect of Camalloy 4 is indeed diminished during multipass welding. We propose a carefully selected elevated interpass hold temperature and demonstrate that this restores the LTT capability to successfully mitigate residual tensile stresses.

This paper is part of a thematic issue on Nuclear Materials.

KEYWORDS:

• Martensitic transformation
• gas metal arc welding
• displacive transformation
• low stress low distortion welding

Acknowledgements

Complementary funding as well as help with the welding is gratefully acknowledged from Rolls-Royce plc along with helpful suggestions from Dr Paul Hurrell regarding the use of interpass hold temperature.

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

R.J. Moat http://orcid.org/0000-0002-9445-8658

Additional information

Funding

The funding of EPSRC through grants GR/S62840/01 and GR/S62857/01 is acknowledged.