Hydrogen effect on fatigue life of a pipe steel

Transport by pipe is the means more used, at the present time, to convey energies of their point of extraction until their field sites final. To limit any risk of explosion or of escape and thus to limit the geological problems of pollution and the human risks, it is necessary to be able to know the mechanical properties of the steels used in the manufacture of these pipes. With the reduction in oil stocks, it is necessary to find a new energy. Hydrogen is this new energy vector, it thus will also be necessary to be able to transport it. This study makes it possible to emphasize the assignment of the lifespan of hydrogen on a pipeline steel normally used in the transport of gas. The fatigue tests in 3 points bending are carried out on samples not standards because of dimensions of the tube of origin

Experimental-numerical characterization of the fracture behaviour of P264GH steel notched pipes subject to internal pressure

The rupture phenomenon of a mechanical structure requires critical consideration, because of its safety constructions. A detailed experiment of material features as well as the Young’s modulus, yield strength, material toughness or fracture resistance provides useful information to predict the life integrity of a pipe structure. This paper presents the most accurate experimental techniques for characterization of a pipe-like structure to assess its reliability. Standard traction tests, dynamic Charpy tests and pressure tests were performed to envisage the crack propagation progress. Detailed information on fracture process was obtained by a robust numerical approach using the finite element method

Fatigue Life Prediction of Welded Box Structures

The objective of this study is to predict fatigue life of metal welded boxes. Experimental results of fatigue life are satisfactory predicted using an analytical scheme based on the volumetric approach.Проведено прогнозирование усталостной долговечности сварных коробчатых конструкций. Результаты расчета усталостной долговечности с использованием аналитической схемы, базирующейся на объемном методе, хорошо согласуются с соответствующими экспериментальными данными.Проведено прогнозування довговічності зварних коробчастих конструкцій від утомленості. Результати розрахунку довговічності від утомленості з використанням аналітичної схеми, що базується на об’ємному методі, добре узгоджуються з відповідними експериментальними даними

The effect of hydrogen concentration on fracture of pipeline steels in presence of a notch

International audienceThe comparative assessment of local fracture initiation at notches in API grade pipeline steels: X52, X70 and X100 have been done for conditions of electrochemical hydrogenating. The factor of hydrogen concentration in metal was taken into account. The relationship between hydrogen concentration in metal and work for initiation of the local fracture emanating from the notch has been derived. The existence of some critical hydrogen concentration , which causes the significant loss of local fracture resistance of material, was also shown and discussed

Sensitivity of pipelines with steel API X52 to hydrogen embrittlement

International audienceThe following cases of hydrogen influence on pipeline metal were considered: gaseous hydrogen under internal pressure in notched pipes and electrochemically generated hydrogen on external pipe surface from soil aqueous environment. The burst tests of externally notched pipes under pressure of hydrogen and natural gas (methane) were carried out after the pipe has been exposed to a constant “holding” pressure. It has been shown that even for relatively “soft” test conditions (holding pressure p = 20 bar and ambient temperature) the gaseous hydrogen is able to penetrate into near surface layers of metal and to change the mechanism of local fracture at notch. The sensitivity to hydrogenating of given steel in deoxygenated, near-neutral pH NS4 solution under soft cathodic polarisation was studied and the assessment local strength at notches in pipeline has been made for this conditions. Here, the relationship between hydrogen concentration and failure loading has been found. The existence of some critical hydrogen concentration, which causes the significant loss of local fracture resistance of material, was also shown

The Other Grazers: The Interactions of “Non-Charismatic Microfauna” in Rangelands

The Rangelands archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform March 202

Influence of sand movement in the Sahara on the erosion of pipeline network

The influence of sandblasting on a surface notched of pipeline with API 5L X52 steel is studied. The purpose of this study is to determine the evolution of static characteristics and lifetime of material in both directions of pipeline (Longitudinal (L) and Transverse (T)). Specimens were taken from a pipeline and the material damage was made by projecting corundum particles (aluminium oxide). In order to justify the evolution of mechanical properties of material, residual stress analysis was realized by the technique of X-ray diffraction. The observation of damage mode and distribution of residual stress under the notch tip show that the material hardening, the notch radius and the compressive stress, play together an important role in stabilizing the material mechanical properties

Amelioration des regles de detensionnement des joints soudes

CNRS AR 11813 (1-6) / INIST-CNRS - Institut de l'Information Scientifique et TechniqueSIGLEFRFranc