The field hydrotest and the true strength properties of steel pipelines

摘要

Field hydrotesting of pipelines at test pressures exceeding SYMS has been used for a long time. Some of the original intentions of this test were to eliminate pipes in the line having undermatching tensile properties or greater defects as a result of bursting. As it is doubtful how far the original goals are still valid for modern pipelines, the aim of the paper, restricted to longitudinal seams SAW pipes, is to highlight the today's situation and to assess the test procedure with regard to its effects on the subsequent safety of a pipeline taking into account the modern pipe production in high toughness steels, as given in ISO 3182-2. The relation between tensile specimen properties and relevant pipe properties are shown and the statistical distribution of plastically deformed pipes in a line is discussed.