Título: | STRUCTURAL ASSESSMENT OF PIPELINES WITH BLUNT CORROSION DEFECTS COINCIDENT WITH LONG-SEAM WELDS | |||||||
Autor: |
SERGIO IBAJE OLIVEIRA BUENO |
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Colaborador(es): |
JOSE LUIZ DE FRANCA FREIRE - Orientador ADILSON CARVALHO BENJAMIN - Coorientador |
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Catalogação: | 19/OUT/2007 | Língua(s): | PORTUGUESE - BRAZIL |
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Tipo: | TEXT | Subtipo: | THESIS | |||||
Notas: |
[pt] Todos os dados constantes dos documentos são de inteira responsabilidade de seus autores. Os dados utilizados nas descrições dos documentos estão em conformidade com os sistemas da administração da PUC-Rio. [en] All data contained in the documents are the sole responsibility of the authors. The data used in the descriptions of the documents are in conformity with the systems of the administration of PUC-Rio. |
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Referência(s): |
[pt] https://www.maxwell.vrac.puc-rio.br/projetosEspeciais/ETDs/consultas/conteudo.php?strSecao=resultado&nrSeq=10728&idi=1 [en] https://www.maxwell.vrac.puc-rio.br/projetosEspeciais/ETDs/consultas/conteudo.php?strSecao=resultado&nrSeq=10728&idi=2 |
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DOI: | https://doi.org/10.17771/PUCRio.acad.10728 | |||||||
Resumo: | ||||||||
One of the most important issues that affects pipeline
integrity is corrosion-caused metal loss. This type of
defect can occur over the pipe body, seam or girth welds
or even on heat affected zones. Pipeline remaining
strength criterions are restricted or even prohibited for
assessing corrosion defects coincident with weld regions.
This present work investigated the reliability of the most
common assessment criteria for corroded pipes when defects
were coincident with seam weld region in submerged arc
welded pipes. The tested specimens were C-Mn steel pipe,
from a pipeline manufactured in the 60´s and had operated
for over 30 years. Five external defects were created on
five pipe specimens and pressure tested until rupture.
Stress, charpy V-notch and bending tests were carried out
to find the mechanical properties of the welded joints.
Microstructure and chemical composition from base metal
and weld metal were also analyzed. Residual stresses on
welds were measured. The level 1 criterion (ASME B31G,
085dL, RPA, DNV single and PCORRC) applications have
underestimated failure pressure for spherical shaped
defects. On the other hand, the same criterions have
overestimated failure pressure for rectangular shaped
defects. The level 2 criterions (Effective Area e DNV
complex geometry) application overestimated failure
pressure for all 5 specimens with both spherical and
rectangular shaped defects. Fracture analyses have
indicated that no specimen had a toughness controlled
failure. Internal pit corrosion that was found after
pressure testing is recognized as the most probable cause
of underestimated pressure forecasts.
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