Fatigue Crack Growth on Double Butt Weld with Toe Crack of Pipelines Steel

Hadjoui, Féthi; Benachour, Mustapha; Benguediab, M.

doi:10.4236/msa.2012.39085

Cited by 4 publications

(4 citation statements)

References 14 publications

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“…13 represents the evolution of the specific energy expended U per cycle in function of ΔK in the three zones studied. This energy is given by the following relation [31], [55]:…”

Section: Evolution Of Energy Parametersmentioning

confidence: 99%

“…The finite element analysis performed by Hadjoui [30] for the X60 and X70 steels for a load ratio R = 0.2 shows that the X70 presents a better resistance to fatigue. Recently Maachou [31] analyzed the fatigue crack growth behavior under constant amplitude and variable amplitude loading using terms of energy parameters. The main objective of this work is to study the fatigue crack growth rate of low-carbon micro alloyed steel X70 welded joints used in pipeline manufacturing.…”

Section: Introductionmentioning

confidence: 99%

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Fatigue crack propagation in welded joints X70

Deliou

Bouchouicha

2018

Frattura Ed Integrità Strutturale

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Structural failure assessment approaches take into account local parameters, specimen geometry, loading and material. In the case of welded joints, in addition to these parameters, consideration must be given to the effect of the heterogeneity of properties due to welding. The objective of our work is to study the fatigue crack propagation of welded joint in API X70 pipeline steel. This experimental study focused on welded joints in the different parts, base metal, weld metal and heat affected zone. The concepts of fracture mechanics are used to analyze the harmfulness of defects in welded joints and the main part of fatigue life falls on the crack propagation. The results obtained show that the fatigue crack propagation rate of cracks in the heat affected zone is delayed compared to the other zones. The effect of the microstructure and the quality of submerged arc welding of the studied X70 steel are significant. Tensile tests, hardness and measurement of energetically parameters complemented this work.

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“…13 represents the evolution of the specific energy expended U per cycle in function of ΔK in the three zones studied. This energy is given by the following relation [31], [55]:…”

Section: Evolution Of Energy Parametersmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Fatigue crack propagation in welded joints X70

Deliou

Bouchouicha

2018

Frattura Ed Integrità Strutturale

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“…In exploitation, welded constructions, as well as joints, are often affected by cyclic loading. Such loadings facilitate a crack initiation [1] and its propagation [2], often in the welded section [3]. The initiation of cracks in a welded joint occurs in places of the greatest stress concentration, i.e., in the toe radius.…”

Section: Introductionmentioning

confidence: 99%

Multiparametric Investigation of Welding Techniques on Toe Radius of High Strength Steel at Low-Temperature Levels Using 3D-Scanning Techniques

Randić¹,

Pavletić

Turkalj

2019

Metals

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To avoid the occurrence of surface cracks at the welds, it is important to lower the stress concentration in the zone of the weld face by an appropriate choice of parameters. A plethora of experiments was conducted varying four welding techniques. The welded samples were scanned with 3D scanners and the toe radius was measured on each sample. The significance of the obtained results was analyzed using Pareto diagrams. The experiment results analysis shows that the length of the electrode stick-out has a significant influence on the toe radius, while the shielding gas has a great effect on the toe radius. Moreover, with the analysis of results obtained by experiments it was proved that the interaction of the torch angle and the number of cover passes, as well as that of the torch angle and the shielding gas, has a significant influence on the toe radius.

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“…Systematic studies have shown that, for instance, welding residual stresses might lead to a drastic reduction in the fatigue strength of welded elements. In multi-cycle fatigue (N > 106 cycles), the effect of residual stresses is comparable to the effect of stress concentration [4]. Surprisingly, the effect of residual stresses on the fatigue life of welded elements, specifically with regards to relieving harmful tensile residual stresses and introducing beneficial compressive residual stresses in the weld toe zones, is significant.…”

Section: Introductionmentioning

confidence: 99%

Residual Stress Measurements on the TIG Weld Joint of 57Fe15Cr25Ni Austenitic Steel for Structural Material Applications by Means X-Ray Diffraction Techniques

Parikin

Ismoyo

Iskandar

et al. 2017

MST

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Measurements of residual stress on the 57Fe25Cr15Ni steel plate with no-filler TIG-welding process were carried out. This work was conducted to determine the nature of weld ability in synthesized steel. The bulks were formed in a dimension of 30x20x7 mm 3 to ease data retrieval. Results show that the largest residual stress occurred in the weld metal area, amounting to 82.40 MPa with lattice stretching of 0.18%. Conversely, the values decreased to 65.92 MPa and a stretch of 0.14% in the HAZ area. This residual stress is a tensile stress that can reduce the mechanical strength of the material since it adds to the applied loads. This was confirmed by microstructure observations. The carbon content was very high in the dark lines. Weaken materials usually start from this side and could initiate the intergranular cracks that rapidly migrate among its grain boundaries. Abstrak Pengukuran Tegangan Sisa pada Sambungan Las-TIG Bahan Struktur Baja Austenitik 57Fe15Cr25NiMenggunakan Teknik Difraksi Sinar-X. Pengukuran tegangan sisa pada pelat baja 57Fe15Cr25Ni akibat proses pengelasan TIG tanpa filler telah dilakukan. Pekerjaan ini dilakukan untuk mengetahui sifat mampu las dari bahan pelat baja. Bahan 'bulk' dibentuk plat dengan dimensi 30x20x7 mm3 untuk memudahkan pengambilan data. Hasil penelitian menunjukkan bahwa tegangan sisa terbesar terjadi di daerah pusat las, sekitar 82,40 MPa dengan kisi peregangan 0,18% dan turun pada sekitar 65,92 MPa dengan regangan sebesar 0,14% di daerah HAZ. Tegangan sisa ini adalah tegangan tarik yang dapat mengurangi kekuatan mekanik material karena mampu menambah beban terpakai. Hal ini ditegaskan dengan pengamatan mikrostruktur. Kandungan karbon sangat tinggi di garis hitam. Pelemahan bahan biasanya dimulai dari sisi ini dan bisa mengawali retakan intergranular, yang dengan cepat dapat bermigrasi di antara batas butirnya.

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Fatigue Crack Growth on Double Butt Weld with Toe Crack of Pipelines Steel

Cited by 4 publications

References 14 publications

Fatigue crack propagation in welded joints X70

Fatigue crack propagation in welded joints X70

Multiparametric Investigation of Welding Techniques on Toe Radius of High Strength Steel at Low-Temperature Levels Using 3D-Scanning Techniques

Residual Stress Measurements on the TIG Weld Joint of 57Fe15Cr25Ni Austenitic Steel for Structural Material Applications by Means X-Ray Diffraction Techniques

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