Fracture mechanical characterisation of ferrite-austenite dissimilar metal welds (DMWs) for elevated temperature service in view of metallurgical mis-match

Pekka Nevasmaa, Petra Holmström, Päivi Karjalainen-Roikonen, Teemu Sarikka, Matias Ahonen, Roman Mouginot, Ulla Ehrnsten, Anssi Brederholm, Pertti Aaltonen, Hannu Hänninen

Research output: Chapter in Book/Report/Conference proceedingChapter or book articleProfessional

Abstract

A characteristic feature of dissimilar metal weld (DMW) is the metallurgical and material property mis-match resulting from a steep gradient of microstructures with significantly different strength and toughness properties. This mis-match inevitably affects the entire failure behaviour of DMWs under external operational loads, not only from crack initiation standpoint, but especially regarding the development of crack driving force accentuating crack path deviation and subsequent crack growth. The determination of relevant fracture toughness properties for all the different microstructural regions of the DMW is of utmost importance for successful structural integrity and lifetime analyses. This paper deals with experimental material characterisation of two configurations of ferrite (SA508)-austenite (Type 304/316) DMWs made using (i) a beveled V-groove and Alloy 82/182 filler metal with a buttering layer and (ii) a narrow-gap weld and Alloy 52 filler metal without any buttering. Results of hardness surveys and fracture mechanical (J-R curve) tests are presented and analysed. The role of mis-match (i.e. metallurgical constraint) in e.g. promoting sudden crack path deviations is discussed in the light of detailed post-test sectioning metallography and specimen fractography identifying the actual crack initiation and propagation path.
Original languageEnglish
Title of host publicationBaltica IX. International Conference on Life Management and Maintenance for Power Plants. VTT Technology 106
Place of PublicationEspoo
PublisherVTT Technical Research Centre of Finland
Pages152-173
ISBN (Print)978-951-38-8025-5 (USB flash drive), 978-951-38-8026-2 (URL: http://www.vtt.fi/publications/index.jsp
Publication statusPublished - 2013
MoE publication typeD2 Article in professional manuals or guides or professional information systems or text book material

Fingerprint

Dissimilar metals
Austenite
Ferrite
Welds
Filler metals
Cracks
Crack initiation
Crack propagation
Temperature
Fractography
Metallography
Structural integrity
Toughness
Fracture toughness
Materials properties
Hardness
Microstructure

Cite this

Nevasmaa, P., Holmström, P., Karjalainen-Roikonen, P., Sarikka, T., Ahonen, M., Mouginot, R., ... Hänninen, H. (2013). Fracture mechanical characterisation of ferrite-austenite dissimilar metal welds (DMWs) for elevated temperature service in view of metallurgical mis-match. In Baltica IX. International Conference on Life Management and Maintenance for Power Plants. VTT Technology 106 (pp. 152-173). Espoo: VTT Technical Research Centre of Finland.
Nevasmaa, Pekka ; Holmström, Petra ; Karjalainen-Roikonen, Päivi ; Sarikka, Teemu ; Ahonen, Matias ; Mouginot, Roman ; Ehrnsten, Ulla ; Brederholm, Anssi ; Aaltonen, Pertti ; Hänninen, Hannu. / Fracture mechanical characterisation of ferrite-austenite dissimilar metal welds (DMWs) for elevated temperature service in view of metallurgical mis-match. Baltica IX. International Conference on Life Management and Maintenance for Power Plants. VTT Technology 106. Espoo : VTT Technical Research Centre of Finland, 2013. pp. 152-173
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abstract = "A characteristic feature of dissimilar metal weld (DMW) is the metallurgical and material property mis-match resulting from a steep gradient of microstructures with significantly different strength and toughness properties. This mis-match inevitably affects the entire failure behaviour of DMWs under external operational loads, not only from crack initiation standpoint, but especially regarding the development of crack driving force accentuating crack path deviation and subsequent crack growth. The determination of relevant fracture toughness properties for all the different microstructural regions of the DMW is of utmost importance for successful structural integrity and lifetime analyses. This paper deals with experimental material characterisation of two configurations of ferrite (SA508)-austenite (Type 304/316) DMWs made using (i) a beveled V-groove and Alloy 82/182 filler metal with a buttering layer and (ii) a narrow-gap weld and Alloy 52 filler metal without any buttering. Results of hardness surveys and fracture mechanical (J-R curve) tests are presented and analysed. The role of mis-match (i.e. metallurgical constraint) in e.g. promoting sudden crack path deviations is discussed in the light of detailed post-test sectioning metallography and specimen fractography identifying the actual crack initiation and propagation path.",
author = "Pekka Nevasmaa and Petra Holmstr{\"o}m and P{\"a}ivi Karjalainen-Roikonen and Teemu Sarikka and Matias Ahonen and Roman Mouginot and Ulla Ehrnsten and Anssi Brederholm and Pertti Aaltonen and Hannu H{\"a}nninen",
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Nevasmaa, P, Holmström, P, Karjalainen-Roikonen, P, Sarikka, T, Ahonen, M, Mouginot, R, Ehrnsten, U, Brederholm, A, Aaltonen, P & Hänninen, H 2013, Fracture mechanical characterisation of ferrite-austenite dissimilar metal welds (DMWs) for elevated temperature service in view of metallurgical mis-match. in Baltica IX. International Conference on Life Management and Maintenance for Power Plants. VTT Technology 106. VTT Technical Research Centre of Finland, Espoo, pp. 152-173.

Fracture mechanical characterisation of ferrite-austenite dissimilar metal welds (DMWs) for elevated temperature service in view of metallurgical mis-match. / Nevasmaa, Pekka; Holmström, Petra; Karjalainen-Roikonen, Päivi; Sarikka, Teemu; Ahonen, Matias; Mouginot, Roman; Ehrnsten, Ulla; Brederholm, Anssi; Aaltonen, Pertti; Hänninen, Hannu.

Baltica IX. International Conference on Life Management and Maintenance for Power Plants. VTT Technology 106. Espoo : VTT Technical Research Centre of Finland, 2013. p. 152-173.

Research output: Chapter in Book/Report/Conference proceedingChapter or book articleProfessional

TY - CHAP

T1 - Fracture mechanical characterisation of ferrite-austenite dissimilar metal welds (DMWs) for elevated temperature service in view of metallurgical mis-match

AU - Nevasmaa, Pekka

AU - Holmström, Petra

AU - Karjalainen-Roikonen, Päivi

AU - Sarikka, Teemu

AU - Ahonen, Matias

AU - Mouginot, Roman

AU - Ehrnsten, Ulla

AU - Brederholm, Anssi

AU - Aaltonen, Pertti

AU - Hänninen, Hannu

N1 - Project code: 71232

PY - 2013

Y1 - 2013

N2 - A characteristic feature of dissimilar metal weld (DMW) is the metallurgical and material property mis-match resulting from a steep gradient of microstructures with significantly different strength and toughness properties. This mis-match inevitably affects the entire failure behaviour of DMWs under external operational loads, not only from crack initiation standpoint, but especially regarding the development of crack driving force accentuating crack path deviation and subsequent crack growth. The determination of relevant fracture toughness properties for all the different microstructural regions of the DMW is of utmost importance for successful structural integrity and lifetime analyses. This paper deals with experimental material characterisation of two configurations of ferrite (SA508)-austenite (Type 304/316) DMWs made using (i) a beveled V-groove and Alloy 82/182 filler metal with a buttering layer and (ii) a narrow-gap weld and Alloy 52 filler metal without any buttering. Results of hardness surveys and fracture mechanical (J-R curve) tests are presented and analysed. The role of mis-match (i.e. metallurgical constraint) in e.g. promoting sudden crack path deviations is discussed in the light of detailed post-test sectioning metallography and specimen fractography identifying the actual crack initiation and propagation path.

AB - A characteristic feature of dissimilar metal weld (DMW) is the metallurgical and material property mis-match resulting from a steep gradient of microstructures with significantly different strength and toughness properties. This mis-match inevitably affects the entire failure behaviour of DMWs under external operational loads, not only from crack initiation standpoint, but especially regarding the development of crack driving force accentuating crack path deviation and subsequent crack growth. The determination of relevant fracture toughness properties for all the different microstructural regions of the DMW is of utmost importance for successful structural integrity and lifetime analyses. This paper deals with experimental material characterisation of two configurations of ferrite (SA508)-austenite (Type 304/316) DMWs made using (i) a beveled V-groove and Alloy 82/182 filler metal with a buttering layer and (ii) a narrow-gap weld and Alloy 52 filler metal without any buttering. Results of hardness surveys and fracture mechanical (J-R curve) tests are presented and analysed. The role of mis-match (i.e. metallurgical constraint) in e.g. promoting sudden crack path deviations is discussed in the light of detailed post-test sectioning metallography and specimen fractography identifying the actual crack initiation and propagation path.

M3 - Chapter or book article

SN - 978-951-38-8025-5 (USB flash drive)

SN - 978-951-38-8026-2 (URL: http://www.vtt.fi/publications/index.jsp

SP - 152

EP - 173

BT - Baltica IX. International Conference on Life Management and Maintenance for Power Plants. VTT Technology 106

PB - VTT Technical Research Centre of Finland

CY - Espoo

ER -

Nevasmaa P, Holmström P, Karjalainen-Roikonen P, Sarikka T, Ahonen M, Mouginot R et al. Fracture mechanical characterisation of ferrite-austenite dissimilar metal welds (DMWs) for elevated temperature service in view of metallurgical mis-match. In Baltica IX. International Conference on Life Management and Maintenance for Power Plants. VTT Technology 106. Espoo: VTT Technical Research Centre of Finland. 2013. p. 152-173