innovations in safety analysis of dissimilar metal...

Project LOST:Innovations insafety analysisof dissimilarmetal weldsSebastian Lindqvist

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Cracks have been detected in dissimilar metal welds– safety class 1

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Weld metal, Lincoln TIG 316L &LNS 316L, P240

Ferritic steel,15H2MFA

Buttering layer 1, EA-395/9

Buttering layer 2, EA-400/10T

Buttering layer 3, EA-400/10T

Austenitic stainless steel,X6CrNiTi18-10

Low alloy steel

18MND5

(ferritic steel)

Stainless steel

316LNi-base

Alloy 52

(weld metal)

Current methods to determine the lower boundary fracturetoughness properties are developed for homogeneous materials –Safety concerns when applied to dissimilar metal welds?

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Fracture toughness = J

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Fracture toughness = J or K

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Area of theremaining ligament

Fracture toughness = J

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Remainingligament

Energy stored inthe specimen

Fracture toughness = J

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Remainingligament

Energy stored inthe specimen

Parameter relating themeasured workto the fracture toughness

The η-factors developed for homogeneous materials can be usedfor cracks on the interface between a hard and a soft material

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Crack path –brittle andductile regime

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Lower boundary fracture toughness values areobtained at the fusion boundary, the weak zone

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The model can be used for predicting the fracturetoughness of/adjacent to the weakest zone

Transferability

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Towards better operation of NPPs by utilizingthe full potential of fracture mechanics

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Longeroperation

New material solutions

Reduced material consumption

Sebastian.lindqvist@vtt.fi

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