Structural integrity of Ni-base alloy welds

Hannu Hänninen, Anssi Brederholm, Teemu Sarikka, Roman Mouginot, Petra Holmström, Tapio Saukkonen, Aki Toivonen, Päivi Karjalainen-Roikonen, Pekka Nevasmaa, Heikki Keinänen, Esa Leskelä, Matias Ahonen, Ulla Ehrnsten, Pertti Aaltonen

Research output: Book/ReportReportProfessional

Abstract

The Tekes project Structural integrity of Ni-base alloy welds (SINI) was carried out at Aalto University and VTT during the period from 2010 to 2014. In nuclear industry applications, the degradation of Ni-base alloy dissimilar metal welds (DMWs), both in pressurised water reactor (PWR) and in boiling water reactor (BWR) plants, is an extensive international problem. The project participates with ongoing international cooperation in USA (Electric Power Research Institute EPRI, Alloy 690/52/152 PWSCC Research Collaboration) and in Japan (Tohoku University) for the conduction of new Ni-base alloy research. The research need is actual, especially because indications have been found in the DMWs in the reactor pressure vessel nozzle of BWRs similar to Finnish BWR designs and European pressurised water reactor (EPR PWR) -plant under construction contains a large number of varying and new types of dissimilar metal welds of which no previous experience is available. The main focus of the project was to investigate the weldability of Alloy 690 base metal corresponding filler metal Alloy 52 and the properties of the welded joint. Comparable reactor pressure vessel (RPV) safe-end weld joint was made by narrow-gap tungsten inert gas (TIG) welding with Alloy 52 filler metal for research purposes. Also prototypical BWR reactor pressure vessel (RPV) safe-end weld joint was made with Alloy 82/182 filler metals. Determination of the mechanical properties and characterization of the microstructures of the welded joints were conducted. Crack initiation tests in autoclave were made in different environments. After PINC (Program for the Inspection of Nickel Alloy Components) round-robin program new PARENT (Program to Assess Reliability of Emerging Non-destructive Techniques for Dissimilar Metal Welds) round-robin program was started where VTT participated. Based on the PINC results, new non-destructive testing methods were developed to enhance the reliability of detection and accuracy of sizing of flaws in nickel-based alloy dissimilar metal welds. Separate reports: 1. Holmström, P. (2012), The effect of mismatch on the mechanical properties of a dissimilar metal weld. M.Sc. Thesis, Aalto University, Espoo, Finland, 162 p. + app. 4 p. 2. Mouginot, R. and Hänninen, H. (2013), Microstructures of nickel-base alloy dissimilar metal welds. Aalto University publication series SCIENCE + TECHNOLOGY, 5/2013, https://aaltodoc.aalto.fi/handle/123456789/9006, Aalto University, Espoo, Finland, 178 p. 3. Keinänen, H. (2013), Computational estimation of the risk of hot cracking in narrow gap welding. Research report VTT-R-08369-13, VTT Technical Research Centre of Finland, Espoo, Finland, 27 p. + app. 10 p.
Original languageEnglish
Place of PublicationEspoo
PublisherVTT Technical Research Centre of Finland
Number of pages264
ISBN (Electronic)978-951-38-8260-0
ISBN (Print)978-951-38-8259-4
Publication statusPublished - 2014
MoE publication typeNot Eligible

Publication series

NameVTT Technology
PublisherVTT
Volume175
ISSN (Print)2242-1211
ISSN (Electronic)2242-122X

Fingerprint

Structural integrity
Welds
Dissimilar metals
Filler metals
Boiling water reactors
Pressurized water reactors
Pressure vessels
Nickel alloys
Application programs
Inspection
Nickel
Inert gas welding
Mechanical properties
Microstructure
Nuclear industry
Weldability
International cooperation
Autoclaves
Nondestructive examination
Crack initiation

Keywords

  • nickel-base alloys
  • welding
  • weld metal
  • dissimilar metal welds
  • nuclear power plant
  • environment-assisted cracking
  • fracture toughness
  • scanning electron microscopy
  • NDT

Cite this

Hänninen, H., Brederholm, A., Sarikka, T., Mouginot, R., Holmström, P., Saukkonen, T., ... Aaltonen, P. (2014). Structural integrity of Ni-base alloy welds. Espoo: VTT Technical Research Centre of Finland. VTT Technology, Vol.. 175
Hänninen, Hannu ; Brederholm, Anssi ; Sarikka, Teemu ; Mouginot, Roman ; Holmström, Petra ; Saukkonen, Tapio ; Toivonen, Aki ; Karjalainen-Roikonen, Päivi ; Nevasmaa, Pekka ; Keinänen, Heikki ; Leskelä, Esa ; Ahonen, Matias ; Ehrnsten, Ulla ; Aaltonen, Pertti. / Structural integrity of Ni-base alloy welds. Espoo : VTT Technical Research Centre of Finland, 2014. 264 p. (VTT Technology, Vol. 175).
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author = "Hannu H{\"a}nninen and Anssi Brederholm and Teemu Sarikka and Roman Mouginot and Petra Holmstr{\"o}m and Tapio Saukkonen and Aki Toivonen and P{\"a}ivi Karjalainen-Roikonen and Pekka Nevasmaa and Heikki Kein{\"a}nen and Esa Leskel{\"a} and Matias Ahonen and Ulla Ehrnsten and Pertti Aaltonen",
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Hänninen, H, Brederholm, A, Sarikka, T, Mouginot, R, Holmström, P, Saukkonen, T, Toivonen, A, Karjalainen-Roikonen, P, Nevasmaa, P, Keinänen, H, Leskelä, E, Ahonen, M, Ehrnsten, U & Aaltonen, P 2014, Structural integrity of Ni-base alloy welds. VTT Technology, vol. 175, VTT Technical Research Centre of Finland, Espoo.

Structural integrity of Ni-base alloy welds. / Hänninen, Hannu; Brederholm, Anssi; Sarikka, Teemu; Mouginot, Roman; Holmström, Petra; Saukkonen, Tapio; Toivonen, Aki; Karjalainen-Roikonen, Päivi; Nevasmaa, Pekka; Keinänen, Heikki; Leskelä, Esa; Ahonen, Matias; Ehrnsten, Ulla; Aaltonen, Pertti.

Espoo : VTT Technical Research Centre of Finland, 2014. 264 p. (VTT Technology, Vol. 175).

Research output: Book/ReportReportProfessional

TY - BOOK

T1 - Structural integrity of Ni-base alloy welds

AU - Hänninen, Hannu

AU - Brederholm, Anssi

AU - Sarikka, Teemu

AU - Mouginot, Roman

AU - Holmström, Petra

AU - Saukkonen, Tapio

AU - Toivonen, Aki

AU - Karjalainen-Roikonen, Päivi

AU - Nevasmaa, Pekka

AU - Keinänen, Heikki

AU - Leskelä, Esa

AU - Ahonen, Matias

AU - Ehrnsten, Ulla

AU - Aaltonen, Pertti

N1 - Project code: 71232

PY - 2014

Y1 - 2014

N2 - The Tekes project Structural integrity of Ni-base alloy welds (SINI) was carried out at Aalto University and VTT during the period from 2010 to 2014. In nuclear industry applications, the degradation of Ni-base alloy dissimilar metal welds (DMWs), both in pressurised water reactor (PWR) and in boiling water reactor (BWR) plants, is an extensive international problem. The project participates with ongoing international cooperation in USA (Electric Power Research Institute EPRI, Alloy 690/52/152 PWSCC Research Collaboration) and in Japan (Tohoku University) for the conduction of new Ni-base alloy research. The research need is actual, especially because indications have been found in the DMWs in the reactor pressure vessel nozzle of BWRs similar to Finnish BWR designs and European pressurised water reactor (EPR PWR) -plant under construction contains a large number of varying and new types of dissimilar metal welds of which no previous experience is available. The main focus of the project was to investigate the weldability of Alloy 690 base metal corresponding filler metal Alloy 52 and the properties of the welded joint. Comparable reactor pressure vessel (RPV) safe-end weld joint was made by narrow-gap tungsten inert gas (TIG) welding with Alloy 52 filler metal for research purposes. Also prototypical BWR reactor pressure vessel (RPV) safe-end weld joint was made with Alloy 82/182 filler metals. Determination of the mechanical properties and characterization of the microstructures of the welded joints were conducted. Crack initiation tests in autoclave were made in different environments. After PINC (Program for the Inspection of Nickel Alloy Components) round-robin program new PARENT (Program to Assess Reliability of Emerging Non-destructive Techniques for Dissimilar Metal Welds) round-robin program was started where VTT participated. Based on the PINC results, new non-destructive testing methods were developed to enhance the reliability of detection and accuracy of sizing of flaws in nickel-based alloy dissimilar metal welds. Separate reports: 1. Holmström, P. (2012), The effect of mismatch on the mechanical properties of a dissimilar metal weld. M.Sc. Thesis, Aalto University, Espoo, Finland, 162 p. + app. 4 p. 2. Mouginot, R. and Hänninen, H. (2013), Microstructures of nickel-base alloy dissimilar metal welds. Aalto University publication series SCIENCE + TECHNOLOGY, 5/2013, https://aaltodoc.aalto.fi/handle/123456789/9006, Aalto University, Espoo, Finland, 178 p. 3. Keinänen, H. (2013), Computational estimation of the risk of hot cracking in narrow gap welding. Research report VTT-R-08369-13, VTT Technical Research Centre of Finland, Espoo, Finland, 27 p. + app. 10 p.

AB - The Tekes project Structural integrity of Ni-base alloy welds (SINI) was carried out at Aalto University and VTT during the period from 2010 to 2014. In nuclear industry applications, the degradation of Ni-base alloy dissimilar metal welds (DMWs), both in pressurised water reactor (PWR) and in boiling water reactor (BWR) plants, is an extensive international problem. The project participates with ongoing international cooperation in USA (Electric Power Research Institute EPRI, Alloy 690/52/152 PWSCC Research Collaboration) and in Japan (Tohoku University) for the conduction of new Ni-base alloy research. The research need is actual, especially because indications have been found in the DMWs in the reactor pressure vessel nozzle of BWRs similar to Finnish BWR designs and European pressurised water reactor (EPR PWR) -plant under construction contains a large number of varying and new types of dissimilar metal welds of which no previous experience is available. The main focus of the project was to investigate the weldability of Alloy 690 base metal corresponding filler metal Alloy 52 and the properties of the welded joint. Comparable reactor pressure vessel (RPV) safe-end weld joint was made by narrow-gap tungsten inert gas (TIG) welding with Alloy 52 filler metal for research purposes. Also prototypical BWR reactor pressure vessel (RPV) safe-end weld joint was made with Alloy 82/182 filler metals. Determination of the mechanical properties and characterization of the microstructures of the welded joints were conducted. Crack initiation tests in autoclave were made in different environments. After PINC (Program for the Inspection of Nickel Alloy Components) round-robin program new PARENT (Program to Assess Reliability of Emerging Non-destructive Techniques for Dissimilar Metal Welds) round-robin program was started where VTT participated. Based on the PINC results, new non-destructive testing methods were developed to enhance the reliability of detection and accuracy of sizing of flaws in nickel-based alloy dissimilar metal welds. Separate reports: 1. Holmström, P. (2012), The effect of mismatch on the mechanical properties of a dissimilar metal weld. M.Sc. Thesis, Aalto University, Espoo, Finland, 162 p. + app. 4 p. 2. Mouginot, R. and Hänninen, H. (2013), Microstructures of nickel-base alloy dissimilar metal welds. Aalto University publication series SCIENCE + TECHNOLOGY, 5/2013, https://aaltodoc.aalto.fi/handle/123456789/9006, Aalto University, Espoo, Finland, 178 p. 3. Keinänen, H. (2013), Computational estimation of the risk of hot cracking in narrow gap welding. Research report VTT-R-08369-13, VTT Technical Research Centre of Finland, Espoo, Finland, 27 p. + app. 10 p.

KW - nickel-base alloys

KW - welding

KW - weld metal

KW - dissimilar metal welds

KW - nuclear power plant

KW - environment-assisted cracking

KW - fracture toughness

KW - scanning electron microscopy

KW - NDT

M3 - Report

SN - 978-951-38-8259-4

T3 - VTT Technology

BT - Structural integrity of Ni-base alloy welds

PB - VTT Technical Research Centre of Finland

CY - Espoo

ER -

Hänninen H, Brederholm A, Sarikka T, Mouginot R, Holmström P, Saukkonen T et al. Structural integrity of Ni-base alloy welds. Espoo: VTT Technical Research Centre of Finland, 2014. 264 p. (VTT Technology, Vol. 175).