A crack-location correction for T0                                                  analysis of an alloy 52 dissimilar metal weld

Sebastian Lindqvist; Matias Ahonen; Jari Lydman; Pentti Arffman; Hannu Hänninen

doi:10.1016/j.engfracmech.2019.03.001

A crack-location correction for T₀ analysis of an alloy 52 dissimilar metal weld

Sebastian Lindqvist^*, Matias Ahonen, Jari Lydman, Pentti Arffman, Hannu Hänninen

^*Corresponding author for this work

Aalto University

Research output: Contribution to journal › Article › Scientific › peer-review

4 Citations (Scopus)

Abstract

For narrow-gap Alloy 52 dissimilar metal welds, the fusion boundary between the ferritic pressure vessel steel and austenitic Ni-base alloy weld metal is the weakest region from fracture mechanical perspective. Producing of the pre-crack for fracture toughness test specimens in the fusion boundary region to determine T₀ is challenging. For pre-cracks further away from the fusion boundary, the brittle fracture initiation does not necessarily occur on the initial crack plane, but rather in the fusion boundary region. This offset in initiation site can increase the measured fracture toughness leading to a nonconservative T₀ estimate. In this study, a method is proposed for correcting the fracture toughness for crack location and obtaining a lower boundary fracture toughness curve. The crack-location correction shows promise for analysing T₀ of specimens with pre-cracks systematically at a significant distance from the weakest region, but with brittle fracture initiation still occurring at the weakest location.

Original language	English
Pages (from-to)	320-334
Journal	Engineering Fracture Mechanics
Volume	214
DOIs	https://doi.org/10.1016/j.engfracmech.2019.03.001
Publication status	Published - 1 Jun 2019
MoE publication type	A1 Journal article-refereed

Funding

The results for this paper originate from the NIWEL-project (Nickel-Base Alloy Welding Forum) funded by the Finnish Funding Agency for Technology and Innovation (TEKES), Scandinavian NPP Industry and VTT. The writing was funded by the project LOST (Long term operational aspects of structural integrity) that was part of SAFIR2018 (The Finnish Research Programme on Nuclear Power Plant Safety 2015–2018).

Keywords

Brittle fracture
Brittle fracture initiation
Crack path
Dissimilar metal weld
Master Curve

Access to Document

10.1016/j.engfracmech.2019.03.001

Cite this

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title = "A crack-location correction for T0 analysis of an alloy 52 dissimilar metal weld",

abstract = " For narrow-gap Alloy 52 dissimilar metal welds, the fusion boundary between the ferritic pressure vessel steel and austenitic Ni-base alloy weld metal is the weakest region from fracture mechanical perspective. Producing of the pre-crack for fracture toughness test specimens in the fusion boundary region to determine T0 is challenging. For pre-cracks further away from the fusion boundary, the brittle fracture initiation does not necessarily occur on the initial crack plane, but rather in the fusion boundary region. This offset in initiation site can increase the measured fracture toughness leading to a nonconservative T0 estimate. In this study, a method is proposed for correcting the fracture toughness for crack location and obtaining a lower boundary fracture toughness curve. The crack-location correction shows promise for analysing T0 of specimens with pre-cracks systematically at a significant distance from the weakest region, but with brittle fracture initiation still occurring at the weakest location. ",

keywords = "Brittle fracture, Brittle fracture initiation, Crack path, Dissimilar metal weld, Master Curve",

author = "Sebastian Lindqvist and Matias Ahonen and Jari Lydman and Pentti Arffman and Hannu H{\"a}nninen",

year = "2019",

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doi = "10.1016/j.engfracmech.2019.03.001",

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journal = "Engineering Fracture Mechanics",

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T1 - A crack-location correction for T0 analysis of an alloy 52 dissimilar metal weld

AU - Lindqvist, Sebastian

AU - Ahonen, Matias

AU - Lydman, Jari

AU - Arffman, Pentti

AU - Hänninen, Hannu

PY - 2019/6/1

Y1 - 2019/6/1

N2 - For narrow-gap Alloy 52 dissimilar metal welds, the fusion boundary between the ferritic pressure vessel steel and austenitic Ni-base alloy weld metal is the weakest region from fracture mechanical perspective. Producing of the pre-crack for fracture toughness test specimens in the fusion boundary region to determine T0 is challenging. For pre-cracks further away from the fusion boundary, the brittle fracture initiation does not necessarily occur on the initial crack plane, but rather in the fusion boundary region. This offset in initiation site can increase the measured fracture toughness leading to a nonconservative T0 estimate. In this study, a method is proposed for correcting the fracture toughness for crack location and obtaining a lower boundary fracture toughness curve. The crack-location correction shows promise for analysing T0 of specimens with pre-cracks systematically at a significant distance from the weakest region, but with brittle fracture initiation still occurring at the weakest location.

AB - For narrow-gap Alloy 52 dissimilar metal welds, the fusion boundary between the ferritic pressure vessel steel and austenitic Ni-base alloy weld metal is the weakest region from fracture mechanical perspective. Producing of the pre-crack for fracture toughness test specimens in the fusion boundary region to determine T0 is challenging. For pre-cracks further away from the fusion boundary, the brittle fracture initiation does not necessarily occur on the initial crack plane, but rather in the fusion boundary region. This offset in initiation site can increase the measured fracture toughness leading to a nonconservative T0 estimate. In this study, a method is proposed for correcting the fracture toughness for crack location and obtaining a lower boundary fracture toughness curve. The crack-location correction shows promise for analysing T0 of specimens with pre-cracks systematically at a significant distance from the weakest region, but with brittle fracture initiation still occurring at the weakest location.

KW - Brittle fracture

KW - Brittle fracture initiation

KW - Crack path

KW - Dissimilar metal weld

KW - Master Curve

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VL - 214

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EP - 334

JO - Engineering Fracture Mechanics

JF - Engineering Fracture Mechanics

ER -

A crack-location correction for T₀ analysis of an alloy 52 dissimilar metal weld

Abstract

Funding

Keywords

Access to Document

Other files and links

Fingerprint

SAFIR 2018: The Finnish Research Programme on Nuclear Power Plant Safety 2015 - 2018

Cite this

A crack-location correction for T0 analysis of an alloy 52 dissimilar metal weld

Abstract

Funding

Keywords

Access to Document

Other files and links

Fingerprint

Projects

SAFIR 2018: The Finnish Research Programme on Nuclear Power Plant Safety 2015 - 2018

Cite this

A crack-location correction for T₀ analysis of an alloy 52 dissimilar metal weld