Effect of mechanical mismatch on fracture mechanical behavior of SA 508 - Alloy 52 narrow gap dissimilar metal weld

Teemu Sarikka, Matias Ahonen, Roman Mouginot, Pekka Nevasmaa, Päivi Karjalainen-Roikonen, Ulla Ehrnstén, Hannu Hänninen

    Research output: Contribution to journalArticleScientificpeer-review

    6 Citations (Scopus)

    Abstract

    In modern pressurized water reactor (PWR) designs, dissimilar metal welds (DMW) between the reactor pressure vessel (RPV) nozzles and safe-ends connected to the main coolant pipes are manufactured using a narrow-gap welding (NGW) technique. In addition to the new weld design, the filler metals have been changed from conventional Alloys 82 and 182 to higher Cr containing Alloys 52 and 152 to ensure the structural integrity of the welds during long term operation. The changes in weld design and filler metal have an effect on the mechanical mismatch state of the DMW which has an effect on the fracture behavior of the weld. For the experimental determination of the local strength variations and the fracture mechanical behavior of a modern NG-DMW, a weld mock-up consisting of SA 508 pressure vessel steel with AISI 309L/308L cladding, AISI 304 piping steel, and Alloy 52 weld metal was manufactured. The NG-DMW was characterized in both as-welded and post-weld heat treated (PWHT) conditions. The results showed that the highest strength mismatch existed between the carbon-depleted zone (CDZ) in the SA 508 heat-affected zone (HAZ) and the Alloy 52 weld metal. High fracture toughness values were observed for the different zones of the weld and the crack propagation occurred towards the softer SA 508 HAZ CDZ.
    Original languageEnglish
    Pages (from-to)30-42
    Number of pages13
    JournalInternational Journal of Pressure Vessels and Piping
    Volume157
    DOIs
    Publication statusPublished - 1 Nov 2017
    MoE publication typeA1 Journal article-refereed

    Fingerprint

    Dissimilar metals
    Welds
    Filler metals
    Heat affected zone
    Carbon
    Metals
    Steel
    Pressurized water reactors
    Structural integrity
    Steel structures
    Pressure vessels
    Coolants
    Fracture toughness

    Keywords

    • alloy 52
    • dissimilar metal weld
    • fracture resistance
    • low-alloy steel
    • narrow-gap welding
    • strength mismatch

    Cite this

    Sarikka, Teemu ; Ahonen, Matias ; Mouginot, Roman ; Nevasmaa, Pekka ; Karjalainen-Roikonen, Päivi ; Ehrnstén, Ulla ; Hänninen, Hannu. / Effect of mechanical mismatch on fracture mechanical behavior of SA 508 - Alloy 52 narrow gap dissimilar metal weld. In: International Journal of Pressure Vessels and Piping. 2017 ; Vol. 157. pp. 30-42.
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    abstract = "In modern pressurized water reactor (PWR) designs, dissimilar metal welds (DMW) between the reactor pressure vessel (RPV) nozzles and safe-ends connected to the main coolant pipes are manufactured using a narrow-gap welding (NGW) technique. In addition to the new weld design, the filler metals have been changed from conventional Alloys 82 and 182 to higher Cr containing Alloys 52 and 152 to ensure the structural integrity of the welds during long term operation. The changes in weld design and filler metal have an effect on the mechanical mismatch state of the DMW which has an effect on the fracture behavior of the weld. For the experimental determination of the local strength variations and the fracture mechanical behavior of a modern NG-DMW, a weld mock-up consisting of SA 508 pressure vessel steel with AISI 309L/308L cladding, AISI 304 piping steel, and Alloy 52 weld metal was manufactured. The NG-DMW was characterized in both as-welded and post-weld heat treated (PWHT) conditions. The results showed that the highest strength mismatch existed between the carbon-depleted zone (CDZ) in the SA 508 heat-affected zone (HAZ) and the Alloy 52 weld metal. High fracture toughness values were observed for the different zones of the weld and the crack propagation occurred towards the softer SA 508 HAZ CDZ.",
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    Effect of mechanical mismatch on fracture mechanical behavior of SA 508 - Alloy 52 narrow gap dissimilar metal weld. / Sarikka, Teemu; Ahonen, Matias; Mouginot, Roman; Nevasmaa, Pekka; Karjalainen-Roikonen, Päivi; Ehrnstén, Ulla; Hänninen, Hannu.

    In: International Journal of Pressure Vessels and Piping, Vol. 157, 01.11.2017, p. 30-42.

    Research output: Contribution to journalArticleScientificpeer-review

    TY - JOUR

    T1 - Effect of mechanical mismatch on fracture mechanical behavior of SA 508 - Alloy 52 narrow gap dissimilar metal weld

    AU - Sarikka, Teemu

    AU - Ahonen, Matias

    AU - Mouginot, Roman

    AU - Nevasmaa, Pekka

    AU - Karjalainen-Roikonen, Päivi

    AU - Ehrnstén, Ulla

    AU - Hänninen, Hannu

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    N2 - In modern pressurized water reactor (PWR) designs, dissimilar metal welds (DMW) between the reactor pressure vessel (RPV) nozzles and safe-ends connected to the main coolant pipes are manufactured using a narrow-gap welding (NGW) technique. In addition to the new weld design, the filler metals have been changed from conventional Alloys 82 and 182 to higher Cr containing Alloys 52 and 152 to ensure the structural integrity of the welds during long term operation. The changes in weld design and filler metal have an effect on the mechanical mismatch state of the DMW which has an effect on the fracture behavior of the weld. For the experimental determination of the local strength variations and the fracture mechanical behavior of a modern NG-DMW, a weld mock-up consisting of SA 508 pressure vessel steel with AISI 309L/308L cladding, AISI 304 piping steel, and Alloy 52 weld metal was manufactured. The NG-DMW was characterized in both as-welded and post-weld heat treated (PWHT) conditions. The results showed that the highest strength mismatch existed between the carbon-depleted zone (CDZ) in the SA 508 heat-affected zone (HAZ) and the Alloy 52 weld metal. High fracture toughness values were observed for the different zones of the weld and the crack propagation occurred towards the softer SA 508 HAZ CDZ.

    AB - In modern pressurized water reactor (PWR) designs, dissimilar metal welds (DMW) between the reactor pressure vessel (RPV) nozzles and safe-ends connected to the main coolant pipes are manufactured using a narrow-gap welding (NGW) technique. In addition to the new weld design, the filler metals have been changed from conventional Alloys 82 and 182 to higher Cr containing Alloys 52 and 152 to ensure the structural integrity of the welds during long term operation. The changes in weld design and filler metal have an effect on the mechanical mismatch state of the DMW which has an effect on the fracture behavior of the weld. For the experimental determination of the local strength variations and the fracture mechanical behavior of a modern NG-DMW, a weld mock-up consisting of SA 508 pressure vessel steel with AISI 309L/308L cladding, AISI 304 piping steel, and Alloy 52 weld metal was manufactured. The NG-DMW was characterized in both as-welded and post-weld heat treated (PWHT) conditions. The results showed that the highest strength mismatch existed between the carbon-depleted zone (CDZ) in the SA 508 heat-affected zone (HAZ) and the Alloy 52 weld metal. High fracture toughness values were observed for the different zones of the weld and the crack propagation occurred towards the softer SA 508 HAZ CDZ.

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