Título: | EVALUATION OF THE EFFECTS OF REPLACEMENT OF HEMATITE BY WUSTITE ON OXIDIZING ELECTRODES COATING FOR UNDERWATER WET WELDING | |||||||
Autor: |
FREDY AUGUSTO FUENTES FERREIRA |
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Colaborador(es): |
SIDNEI PACIORNIK - Orientador VALTER ROCHA DOS SANTOS - Coorientador |
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Catalogação: | 22/MAR/2010 | 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=15408&idi=1 [en] https://www.maxwell.vrac.puc-rio.br/projetosEspeciais/ETDs/consultas/conteudo.php?strSecao=resultado&nrSeq=15408&idi=2 |
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DOI: | https://doi.org/10.17771/PUCRio.acad.15408 | |||||||
Resumo: | ||||||||
Underwater wet welding is one of the techniques used in the repair of
underwater oil and gas platforms, with a large expansion in the world nowadays.
Its major advantage over other welding processes is due to its simplicity and ease
of deployment, as it allows the diver to work directly on the submerged portions
of the parts without the protection of an artificial environment, as in the traditional
dry welding. Both oxidizing and rutilic electrodes are used in this type of welding.
In this study we assessed the effects of the use of wustite in partial replacement of
Hematite, a mineral used in the coating of oxidizing electrodes. Five groups of
electrodes were produced with a fixed percentage of the total weight of iron oxide
and varying proportions of FeO and Fe2O3. Four pass welds in the flat position
with 60° angle of inclination between the electrode plate and a 0.5m deep were
performed. Weld metals were evaluated by chemical analysis, microscopy,
diffusible hydrogen and micro-hardness. Digital image analysis methods were
developed to measure inclusion area fraction from OM and SEM images, and the
fraction of micro-constituents by OM. The results showed an increase of proeutectoid
ferrite with increasing wustite content and a decrease with increasing
carbon content, which, by its turn, decreased with increasing wustite content.
Micro-hardness decreased with wustite content and increased with carbon content.
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