Microstructure, texture evolution and mechanical properties of X70 pipeline steel after different thermomechanical treatments

Omale, Joseph; Ohaeri, Enyinnaya; Tiamiyu, A.A.; Eskandari, M.; Mostafijur, K. M.; Szpunar, Jerzy A.

doi:10.1016/j.msea.2017.07.086

Cited by 44 publications

(16 citation statements)

References 33 publications

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“…The microstructure of the weld metal (WM) consists of dominant polygonal ferrite, acicular ferrite around the inclusions, and islands of pearlite (Fig.5c). The microstructure obtained is agreed with a number of studies oriented towards the analysis of the structure [26], [38][39][40][41].…”

Section: Microstructure Analysissupporting

confidence: 82%

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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Section: Microstructure Analysissupporting

confidence: 82%

Fatigue crack propagation in welded joints X70

Deliou

Bouchouicha

2018

Frattura Ed Integrità Strutturale

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“…Meanwhile, there is proof of several kinds of inclusion particles in pipeline steel, mainly sulfide, and oxides of elements such as Ti, Ca, Mg, and Al. , These multicomponent fragments often found in X70 pipeline steel are present due to the complexities associated with microalloying. Interestingly, the location of some inclusion components has been reported as a preferred site for different forms of corrosion, most especially localized/crack related corrosive degradation. − A recent work established that particles of TiN as well as δ-ferrite were quite unfavorable for corrosion resistance in 321 stainless steel. The reason is that incoherence between these inclusions and the steel matrix could result in porosity or voids, which will eventually become preferred sites where corrosion could begin.…”

Section: Results and Discussionmentioning

confidence: 99%

Conversion of Imidazole to N-(3-Aminopropyl)imidazole toward Enhanced Corrosion Protection of Steel in Combination with Carboxymethyl Chitosan Grafted Poly(2-methyl-1-vinylimidazole)

Eduok

Ohaeri

Szpunar

2019

Ind. Eng. Chem. Res.

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In this study, the synthesis route for preparing N-(3aminopropyl)imidazole (APM) from imidazole has been reported via hydrogenation using Raney nickel catalyst. The inhibition performance of the resultant imidazoline product against pipeline steel corrosion has been investigated in CO 2 saturated acidic oilfield formation water. The contributions of carboxymethyl chitosan grafted poly(2-methyl-1vinylimidazole) copolymer (polyCMCh-graf t-polyMVI) newly synthesized from chitosan revealed a synergy of protective capacity in combination with APM. Corrosion inhibition by APM/graft copolymer conjugate is attributed to molecular adsorption and the formation of more stable protective inhibitor films on the steel surface compared to individual compounds. In-depth electrochemical corrosion investigation is reported by means of electrochemical impedance spectroscopy and potentiodynamic polarization as well as surface analytical techniques. Adsorbed ferrous carbonate phases are observed at acid pH with apparently amorphous morphologies. Modeled mechanisms of corrosion and corrosion inhibition have been illustrated from experimental evidence in line with the barrier performance on adsorbed films.

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“…In order to obtain the texture type and distribution pattern of cubic crystal polycrystalline materials, the ODF (orientation distribution function) is used to measure and visualize the texture [34,35,36]. The texture index calculated by the ODF is an important parameter for describing the texture strength of polycrystalline metal materials [37,38,39].…”

Section: Resultsmentioning

confidence: 99%

The Evolution and Distribution of Microstructures in High-Energy Laser-Welded X100 Pipeline Steel

et al. 2019

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High-energy beam welding was introduced for pipeline steel welding to reduce pipeline construction costs and improve the efficiency and safety of oil and gas transportation. Microstructures and their distribution in X100 laser-welded joints, which determine the joints’ strength and toughness, are discussed in this paper. Welded joints were prepared by an automatic 10,000-watt robot-based disc laser-welding platform for 12.8 mm thick X100 pipeline steel. Then, the grain, grain boundary, orientation, and distribution pattern of each zone of the welded joints were studied by optical microscopy (OM), scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), and electron backscattered diffraction (EBSD) analysis techniques. The results showed that the grain boundary density, contents of the high-angle and low-angle grain boundaries, distribution states, and evolution trends of coincident site lattice (CSL) grain boundaries were essentially the same in each zone from the base metal (BM) to the weld of the X100 pipeline steel laser-welded joint. The relative content of grain boundaries above 55°, which were composed of the Σ3 type CSL grain boundary, showed a considerable impact on the mechanical properties of the joint. The content of twin grain boundaries was closely related to the thermal cycles of laser welding, and the effect of the cooling rate was greater than that of the process of austenization.

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Microstructure, texture evolution and mechanical properties of X70 pipeline steel after different thermomechanical treatments

Cited by 44 publications

References 33 publications

Fatigue crack propagation in welded joints X70

Fatigue crack propagation in welded joints X70

Conversion of Imidazole to N-(3-Aminopropyl)imidazole toward Enhanced Corrosion Protection of Steel in Combination with Carboxymethyl Chitosan Grafted Poly(2-methyl-1-vinylimidazole)

The Evolution and Distribution of Microstructures in High-Energy Laser-Welded X100 Pipeline Steel

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