Vol. 7 2, 2017 p 22-30


Article name, authors, abstract and keyword


Research of changes of pipeline metal properties during operation: summary of results and prospective developments of Ufa scolarly tradition

Airat R. Khafizov a, Dmitriy A. Neganov a, Vitaly I. Surikov a, Kabir M. Gumerov b

a Pipeline Transport Institute, LLC (Transneft R&D, LLC), 47a, Sevastopolskiy prospect, Moscow, 117186, Russian Federation

b Research and Development center of pipeline transportation Transneft R&D LLC (STC Transneft R&D), 144/3 Oktyabrya prospect, 450055, Ufa, Bashkortostan, Russian Federation


Abstract: Provision of high reliability and safety of pipeline systems is a major task in the oil and gas industry and its solution requires careful study and identification of possible causes and mechanisms of fracture propagation. One of the little-studied processes is, in particular, the change of mechanical properties of the pipes metal. Despite a number of studies carried out in this sphere, there are still a lot of questions about the influence and consideration of this phenomenon during long-term operation of the pipelines.
An overview of several studies in the pipe metal aging area is given in the article. In particular, there are considered results made by representatives of Ufa scolarly tradition in the field, which make it possible to establish a change in steel mechanical characteristics during a long operation of pipelines, the so called pipe metal aging. Two main ways of the metal characteristics degradation are specified, i.e. a strain aging and hydrogen absorption. Under operating conditions of the underground pipelines, both these phenomena lead to virtually identical results, although in different ways: the pipes metal gradually loses its plastic properties, embrittles and cracks. These phenomena were considered at the level of the microstructure of metals that allows not only understanding the development of degradation processes, but also proposing of the methods for their inhibition. There are also presented works of Ufa scholarly tradition aimed at creating a physical model of the pipelines stress corrosion cracking, which is nowadays one of the main causes of metal fracture at the pipeline mains; though it is unreasonably low studied in the oil pipeline transportation system.

Keywords: main pipeline, metal aging, strain aging, embrittlement, hydrogen absorption, cracking, stress corrosion cracking, dislocation, impact strength

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