Finding critical damage locations by Λ-filtering in finite-element modelling of a girth weld

Holmström, Stefan; Laukkanen, Anssi; Calonius, Kim

doi:10.1016/j.msea.2008.04.107

Cited by 6 publications

(3 citation statements)

References 12 publications

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“…In terms of creep properties, generally for arc welding, improvements in creep performance have been reported for small changes in welding procedure details. Particularly the following weld variables are reported to have made a discernible difference: the joint preparation angle (Hyde, Sun, Becker, & Williams, 2001) (Tanner, Sun, & Hyde, 2012); the width of the HAZ (Albert et al, 2005) (Abe & Tabuchi, 2004); the weld metal creep strength (Bauer, Klenk, Maile, & Roos, 2007;Holmstrom, Laukkanen, & Calonius, 2007); and the PWHT temperature (J. A.…”

Section: Discussionmentioning

confidence: 99%

Development of Welding P92 Pipes Using the Reduced Pressure Electron Beam Welding Process for a Study of Creep Performance

Bagshaw

Punshon

Rothwell

2014

ASME 2014 Symposium on Elevated Temperature Application of Materials for Fossil, Nuclear, and Petrochemical Industries

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Boiler and steam piping components in power plants are fabricated using creep strength enhanced ferritic (CSEF) steels, which often operate at temperatures above 550°C. Modification of alloy content within these steels has produced better creep performance and higher operating temperatures, which increases the process efficiency of power plants. The improved materials, however, are susceptible to type IV cracking at the welded regions. A better understanding of type IV cracking in these materials is required and is the basis of the Technology Strategy Board (TSB) UK funded VALID (Verified Approaches to Life Management & Improved Design of High Temperature Steels for Advanced Steam Plants) project. In order to study the relationship between creep performance and heat input during welding, several welds with varying amounts of heat input and resultant HAZ widths were produced using the electron beam welding process. The welding parameters were developed with the aid of weld process modeling using the finite element (FE) method, in which the welding parameters were optimized to produce low, medium and high heat input welds. In this paper, the modeling approach and the development of electron beam welds in ASTM A387 grade P92 pipe material are presented. Creep specimens were extracted from the welded pipes and testing is ongoing. The authors acknowledge the VALID project partners, contributors and funding body: Air Liquide, Metrode, Polysoude, E.ON New Build & Technology Ltd, UKE.ON, Doosan, Centrica Energy, SSE, Tenaris, TU Chemnitz, The University of Nottingham, The Open University and UK TSB. Paper published with permission.

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Section: Discussionmentioning

confidence: 99%

Development of Welding P92 Pipes Using the Reduced Pressure Electron Beam Welding Process for a Study of Creep Performance

Bagshaw

Punshon

Rothwell

2014

ASME 2014 Symposium on Elevated Temperature Application of Materials for Fossil, Nuclear, and Petrochemical Industries

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“…10-11; The filtering technique does not require local creep ductility values since it is expressed as a ratio dependent on stress and momentary strain only. Previous experience from -filtering has been acquired from finding critical damage locations in simple girth welds [28].…”

Section: Managing Constraint By -Filteringmentioning

confidence: 99%

Modeling and Verification of Creep Strain and Exhaustion in a Welded Steam Mixer

Holmström

Rantala

Laukkanen

et al. 2009

Journal of Pressure Vessel Technology

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Structures operating in the creep regime will consume their creep life at a greater rate in locations where the stress state is aggravated by triaxiality constraints. Many structures, such as the welded steam mixer studied here, also have multiple material zones differing in microstructure and material properties. The three-dimensional structure as such, in addition to interacting material zones, is a great challenge for finite element analysis (FEA), even to accurately pinpoint the critical locations where damage will be found. The studied steam mixer, made of 10CrMo 9-10 steel (P22), has after 100,000 h of service developed severe creep damage in several saddle point positions adjacent to nozzle welds. FE-simulation of long term behavior of this structure has been performed taking developing triaxiality constraints, material zones, and primary to tertiary creep regimes into account. The creep strain rate formulation is based on the logistic creep strain prediction model implemented to ABAQUS, including primary, secondary, and tertiary creep. The results are presented using a filtering technique utilizing the formulation of rigid plastic deformation for describing and quantifying the developing “creep exhaustion.”

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“…The filtering technique does not require local creep ductility values since it is expressed as a ratio dependent on stress and momentary strain only. Previous experience from -filtering has been acquired from finding critical damage locations in simple girth welds [28].…”

Section: Vii/7 Managing Constraint By -Filteringmentioning

confidence: 99%

Modeling and Verification of Creep Strain and Exhaustion in a Welded Steam Mixer

̈m

Laukkanen

Rantala

et al. 2008

Volume 7: Operations, Applications and Components

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Structures operating in the creep regime will consume their creep life at a greater rate in locations where the stress state is aggravated by triaxiality constraints. Many structures, such as the welded steam mixer studied here, also have multiple material zones differing in microstructure and material properties. The 3-dimensional structure as such in addition to interacting material zones is a great challenge for finite element analysis (FEA), even to accurately pinpoint the critical locations where damage will be found. The studied steam mixer, made of 10CrMo 9-10 steel (P22), has after 100 000 hours of service developed severe creep damage in the several saddle point positions adjacent to nozzle welds. FE-simulation of long term behaviour of this structure has been performed taking developing triaxiality constraints, material zones and primary to tertiary creep regimes into account. The creep strain rate formulation is based on the logistic creep strain prediction (LCSP) model implemented to ABAQUS, including primary, secondary and tertiary creep. The results are presented using a filtering technique utilising the formulation of rigid plastic deformation for describing and quantifying the developing “creep exhaustion”.

show abstract

Finding critical damage locations by Λ-filtering in finite-element modelling of a girth weld

Cited by 6 publications

References 12 publications

Development of Welding P92 Pipes Using the Reduced Pressure Electron Beam Welding Process for a Study of Creep Performance

Development of Welding P92 Pipes Using the Reduced Pressure Electron Beam Welding Process for a Study of Creep Performance

Modeling and Verification of Creep Strain and Exhaustion in a Welded Steam Mixer

Modeling and Verification of Creep Strain and Exhaustion in a Welded Steam Mixer

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