This report deals with the research of a standardised methodology for laboratory evaluation of Near Neutral SCC (NNSCC or even called low pH SCC). This phenomenon has gained an increasing interest among both gas companies and steel producers in the attempt to avoid failures and minimise the risk associated with it. Two major objectives can be pointed out. The first one refers to existing pipeline and it is to identify the areas with the highest risk of NNSCC, so that appropriate measures can be taken. For future pipelines, the aim is to produce guidelines for pipe materials, coating, environment and operating service to reduce the risk of NNSCC. One heavy obstacle to an effective progress in the research is however the difficulty to reproduce in a consistent and reliable way the cracking pattern and the mechanism actually observed in the field experience. A research project was therefore launched late 1996 under the supervision of EPRG Corrosion Committee involving four laboratories (namely British Gas R&D, British Steel Swinden Lab, Saltzgitter (former Preussag Stahl) and CSM) with the scope, in a first phase, of defining and developing a standardised experimental methodology to obtain reliable data for crack initiation and propagation. A good consistency and reproducibility among the different laboratories was achieved but the difficulty for a quantitative assessment of NNSCC was however confirmed. Crack like features resulting from test exposure were observed in 53% of the tensile specimens with apparent crack depths of up to 70microns, as well in 43% of the CT specimens. Despite such limitations both developed test methodologies can be profitably applied for investigating the phenomenon. Based on such conclusion a second phase of the project is presently under preparation by EPRG, where the developed test procedures will be used to examine the effect of a range of metallurgical factors on NNSCC.


    Access

    Access via TIB

    Check availability in my library

    Order at Subito €


    Export, share and cite



    Title :

    Test methodologies for the study of near neutral stress corrosion cracking in pipeline steels


    Additional title:

    Prüfmethoden für die Untersuchung der beinahe neutralen Spannungsrisskorrosion in Pipelinestählen


    Contributors:


    Publication date :

    2000


    Size :

    15 Seiten, 17 Bilder, 4 Tabellen, 21 Quellen



    Type of media :

    Conference paper


    Type of material :

    Print


    Language :

    English