This study demonstrates a numerical model to predict the onset of pipe-wall failure for circumferential fillet and longitudinal weld. Numerical methods have been used in the assessment of welding conditions for the safe 'in-service' welding of high-pressure gas pipelines. This has given useful information for the prediction of thermal cycles leading to an estimate of the heat-affected zone (HAZ) hardness and possible cracking. This paper also discusses a new mathematical description of a heat-source representing, a commonly used, manual metal arc (MMA) welding with hydrogen-controlled electrodes. Empirical relationships between welding process inputs, weld bead sizes and shapes define the weldment geometry and control the heat source co-ordinates. The formation of a new three dimensional power density distribution function for a low-hydrogen electrode is also presented. Finite element models using this heat-source have given acceptable correlation with experimental and field welds. The prediction of burn-through has been achieved using thermo-elastoplastic model. This study has investigated earlier work and translates the temperature field into an effective radial deflection in the pipe-wall thickness. This information can be used to calculate a safe working pressure during 'in-service' welding. The simulation of the early stages of pipe-wall failure of circumferential fillet welding using a thermoelastic plastic analysis has been successfully demonstrated.


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    Titel :

    The onset of pipewall failure during "in-service" welding of gas pipelines


    Beteiligte:
    Wahab, M.A. (Autor:in) / Sabapathy, P.N. (Autor:in) / Painter, M.J. (Autor:in)

    Erschienen in:

    Erscheinungsdatum :

    2005


    Format / Umfang :

    9 Seiten, 9 Bilder, 21 Quellen




    Medientyp :

    Aufsatz (Zeitschrift)


    Format :

    Print


    Sprache :

    Englisch




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