Study on the residual stress relaxation in girth-welded steel pipes under bending load using diffraction methods

Journal Article · Thu Feb 02 04:00:00 UTC 2017 · Materials Science and Engineering. A, Structural Materials: Properties, Microstructure and Processing

DOI: https://doi.org/10.1016/j.msea.2017.02.005 · OSTI ID:1346663

Hempel, Nico ^[1]; Bunn, Jeffrey R. ^[2]; Nitschke-Pagel, Thomas ^[3]; Payzant, E. Andrew ^[2]; Dilger, Klaus ^[3]

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1. Braunschweig Univ. of Technology (Germany). Institute of Joining and Welding Langer Kamp
2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
3. Braunschweig Univ. of Technology (Germany). Institute of Joining and Welding Langer Kamp

This research is dedicated to the experimental investigation of the residual stress relaxation in girth-welded pipes due to quasi-static bending loads. Ferritic-pearlitic steel pipes are welded with two passes, resulting in a characteristic residual stress state with high tensile residual stresses at the weld root. Also, four-point bending is applied to generate axial load stress causing changes in the residual stress state. These are determined both on the outer and inner surfaces of the pipes, as well as in the pipe wall, using X-ray and neutron diffraction. Focusing on the effect of tensile load stress, it is revealed that not only the tensile residual stresses are reduced due to exceeding the yield stress, but also the compressive residual stresses for equilibrium reasons. Furthermore, residual stress relaxation occurs both parallel and perpendicular to the applied load stress.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States). High Flux Isotope Reactor (HFIR)
• Sponsoring Organization: USDOE Office of Science (SC)
• Grant/Contract Number: AC05-00OR22725
• OSTI ID: 1346663
• Journal Information: Materials Science and Engineering. A, Structural Materials: Properties, Microstructure and Processing, Journal Name: Materials Science and Engineering. A, Structural Materials: Properties, Microstructure and Processing Vol. 688; ISSN 0921-5093
• Publisher: ElsevierCopyright Statement
• Country of Publication: United States
• Language: English