skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

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

Abstract

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.

Authors:
 [1];  [2];  [3];  [2];  [3]
  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
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). High Flux Isotope Reactor (HFIR)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1346663
Grant/Contract Number:
AC05-00OR22725
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Materials Science and Engineering. A, Structural Materials: Properties, Microstructure and Processing
Additional Journal Information:
Journal Volume: 688; Journal ID: ISSN 0921-5093
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; X-ray diffraction; Neutron scattering; Steel; Welding; Residual stresses

Citation Formats

Hempel, Nico, Bunn, Jeffrey R., Nitschke-Pagel, Thomas, Payzant, E. Andrew, and Dilger, Klaus. Study on the residual stress relaxation in girth-welded steel pipes under bending load using diffraction methods. United States: N. p., 2017. Web. doi:10.1016/j.msea.2017.02.005.
Hempel, Nico, Bunn, Jeffrey R., Nitschke-Pagel, Thomas, Payzant, E. Andrew, & Dilger, Klaus. Study on the residual stress relaxation in girth-welded steel pipes under bending load using diffraction methods. United States. doi:10.1016/j.msea.2017.02.005.
Hempel, Nico, Bunn, Jeffrey R., Nitschke-Pagel, Thomas, Payzant, E. Andrew, and Dilger, Klaus. Thu . "Study on the residual stress relaxation in girth-welded steel pipes under bending load using diffraction methods". United States. doi:10.1016/j.msea.2017.02.005. https://www.osti.gov/servlets/purl/1346663.
@article{osti_1346663,
title = {Study on the residual stress relaxation in girth-welded steel pipes under bending load using diffraction methods},
author = {Hempel, Nico and Bunn, Jeffrey R. and Nitschke-Pagel, Thomas and Payzant, E. Andrew and Dilger, Klaus},
abstractNote = {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.},
doi = {10.1016/j.msea.2017.02.005},
journal = {Materials Science and Engineering. A, Structural Materials: Properties, Microstructure and Processing},
number = ,
volume = 688,
place = {United States},
year = {Thu Feb 02 00:00:00 EST 2017},
month = {Thu Feb 02 00:00:00 EST 2017}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record

Save / Share:
  • This paper is dedicated to the thorough experimental analysis of the residual stresses in the vicinity of tubular welds and the mechanisms involved in their formation. Pipes made of a ferritic-pearlitic structural steel and an austenitic stainless steel are investigated in this study. The pipes feature a similar geometry and are MAG welded with two passes and comparable parameters. Residual strain mappings are carried out using X-ray and neutron diffraction. The combined use of both techniques permits both near-surface and through-wall analyses of the residual stresses. The findings allow for a consistent interpretation of the mechanisms accounting for the formationmore » of the residual stress fields due to the welding process. Since the results are similar for both materials, it can be concluded that residual stresses induced by phase transformations, which can occur in the structural steel, play a minor role in this regard.« less
  • Intergranular stress corrosion cracking (IGSCC) in boiling water reactor (BWR) piping is a problem for the nuclear power industry. Tensile residual stresses induced by welding are an important factor in IGSCC of Type 304 stainless steel pipes. Backlay and heat sink welding can retard IGSCC. 17 refs.
  • A numerical scheme for the determination of thermally induced local residual stresses and their relaxation behavior during heat treatment in the case of butt-welded pipes is described. The procedure is illustrated by considering 304 stainless steel and SAE 1020 steel pipes. The results are compared with available experimental and numerical results.
  • In-situ high energy diffraction microscopy (HEDM) experiments are carried out to analyze the state of combined bending and tension in a Ti-7Al alloy under room temperature creep. Grain-level elastic strain tensors are evaluated from HEDM data. Atomistic calculations are used to predict elastic constants of Ti-7Al, to be used in determination of stress from strain. The stress gradient and residual stresses are successfully determined, which allows the demarcation between macro-/micro-level residual stresses. A cluster of three neighboring grains are identified that highlight the variation of mean and effective stress between grains. Crystallographic orientations and slip characteristics are analyzed for themore » selected grains. It is inferred that the interfaces between loaded grains with markedly different stress triaxiality and slip tendency are potential spots for material damage.« less