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 language | English |
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Title of host publication | Baltica IX. International Conference on Life Management and Maintenance for Power Plants. VTT Technology 106 |
Place of Publication | Espoo |
Publisher | VTT Technical Research Centre of Finland |
Pages | 152-173 |
ISBN (Print) | 978-951-38-8025-5 (USB flash drive), 978-951-38-8026-2 (URL: http://www.vtt.fi/publications/index.jsp |
Publication status | Published - 2013 |
MoE publication type | D2 Article in professional manuals or guides or professional information systems or text book material |