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

Hempel, Nico; Bunn, Jeffrey R.; Nitschke–Pagel, Thomas; Payzant, E. Andrew; Dilger, Klaus

doi:10.1016/j.msea.2017.02.005

Cited by 22 publications

(3 citation statements)

References 20 publications

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“…No stress relaxation for pulsating pressure loads was found as long as the maximum equivalent stress is below the cyclic yield strength. Hempel et al 32 investigated residual stress relaxation in welded steel pipes and concluded that the tensile load stress can generate residual stress relaxation depending on the magnitude and direction of the load as well as the level of residual stresses. Furthermore, these authors clarified also that equivalent von Mises stress identifies locations of plastic yielding and hence locations where residual stress relaxation can occur.…”

Section: State Of the Artmentioning

confidence: 99%

Analysis of residual stress relaxation of aluminum alloys EN AW 6061/‐82 T6 under cyclic loading

Repplinger

Sellen²,

Kędziora

et al. 2021

Fatigue Fract Eng Mat Struct

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Stress relaxation describes the reduction of stress under static or cyclic loading at a constant strain level. Several processes induce intentionally residual stresses, for example, autofrettage of thick-walled pressurized tubes to improve their fatigue life. This well-known process induces residual compressive stresses at the critical inner surface by using a single static but controlled overloading internal pressure. Relaxation of residual stresses due to cyclic loading in service would endanger the effectiveness of autofrettage and could finally lead to unexpected fatigue failure. In this study, strain-controlled experiments up to 500,000 load cycles and amending nonlinear finite element simulations were done for the aluminum alloys EN AW 6061 T6 and EN AW 6082 T6 to study potential cyclic stress relaxation in four-point bending tests after controlled single static plasticization for residual stress generation. This analysis identifies almost stable residual stresses for both materials under different cyclic strain-controlled load levels.

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Section: State Of the Artmentioning

confidence: 99%

Analysis of residual stress relaxation of aluminum alloys EN AW 6061/‐82 T6 under cyclic loading

Repplinger

Sellen²,

Kędziora

et al. 2021

Fatigue Fract Eng Mat Struct

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“…10(a). Furthermore, the axial tensile stresses on the inner surface are balanced by the axial compressive stresses on the FZ and HAZ of girth welding on the outer surface [18]. Therefore, axial bending deformation is produced through the pipe cross section.…”

Section: Structural Response In Case Amentioning

confidence: 99%

A parametric study of thermal and residual stress fields in lined pipe welding

Obeid

Alfano

Bahai

et al. 2017

Thermal Science and Engineering Progress

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Welded lined cylindrical structures such as boilers, pressure vessels and transportation pipes are widely used in the oil and gas industries because an inexpensive outer layer is protected from corrosion by a thinner expensive layer, which is made of a corrosion resistant alloy (CRA). Welding in the lined pipe is of two different types, where the first one, so called weld overlay (lap-weld), is deployed to seal the liner with the outer pipe whilst the other one, known as girth welding (butt-weld), is deposited to join two specimens of lined pipe together. Therefore, the precise prediction of the thermal and residual stress fields due to the combination of two different types of circumferential welding is a major concern regarding welded lined pipes to avoid sudden failure during service. Six parametric studies have been conducted primarily to examine the influence of welding properties (weld overlay and girth welding materials), geometric parameters (weld overlay and liner) and welding process parameters (heat input) on the thermal and residual stress fields. All predicted results obtained from a 3-D FE model based on the ABAQUS code are validated against small-scale experimental results. Furthermore, in this study, the effect of mesh size has been investigated.

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“…voids can be arose due to specific volume differences induced by precipitation, different thermal expansion or shrinkage upon heating or cooling the specimen. It has been known that nucleation, growth and coalescence of voids are deemed as the primary mechanism of ductile material fracture, in which voids growth is particularly important [12]. The initiation of crack at microscopic scale is a dynamic process, which results in difficulties on study of mechanism about deformation and cracking, these defects are known playing a fundamental role in the deformation of materials.…”

Section: Introductionmentioning

confidence: 99%

Micromechanism of Cold Deformation of Two-Phase Polycrystalline Ti–Al Alloy with Void

Feng

Wang

et al. 2019

Materials

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Cold deformation behavior of polycrystalline metallic material is affected by intrinsic defects such as dislocations, voids, inclusions etc. Existing studies on α2(Ti3Al) + γfalse(TiAlfalse) two-phase Ti–Al alloy cover about deformation behavior mainly on macro scale. This paper focuses on the cold deformation mechanism of two-phase Ti–Al alloy at micro scale, and the role of voids in deformation process. Molecular dynamics simulations were performed to study the evolution of micro structure of material under uniaxial tension. Interaction between spherical nano voids with different size and position was also examined in the simulation. The results show that (1) In elastic stage, deformation of the two-phase is coordinated, but Ti3Al is more deformable; (2) In plastic stage, γ phase is the major dislocation source in two-phase alloy; (3) voids detracts the strength of the two-phase alloy, while the position of void affect the degree of this subtraction, voids located at the boundary of α2/γ phase have significant detraction to strength.

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

Cited by 22 publications

References 20 publications

Analysis of residual stress relaxation of aluminum alloys EN AW 6061/‐82 T6 under cyclic loading

Analysis of residual stress relaxation of aluminum alloys EN AW 6061/‐82 T6 under cyclic loading

A parametric study of thermal and residual stress fields in lined pipe welding

Micromechanism of Cold Deformation of Two-Phase Polycrystalline Ti–Al Alloy with Void

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