Mechanical Properties of High-Nb X80 Steel Weld Pipes for the Second West-to-East Gas Transmission Pipeline Project

Qiao, Guifang; Chen, Xiaowei; Zhang, Zhien; Han, Xiu-lin; Wang, Xu; Liao, Bo; Xiao, Furen

doi:10.1155/2017/7409873

Cited by 9 publications

(4 citation statements)

References 17 publications

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“…Bends are some of key parts of the pipeline projects [1,2]. Recently, in order to maximize the transport efficiency and decrease the construction and transposition costs, the gas pipeline transmission develops toward a larger diameter and/ or higher operation pressure; thereby, the high strength X80 steel grade and heavy-wall pipe over 22 mm have been applied to many long-distance transmission pipeline projects [3,4], such as the ird West-to-East Gas Transmission Pipeline Project and the Sino-Russian Gas Transmission Pipeline Project. Contemporaneously, heavy-wall hot bends have been developed.…”

Section: Introductionmentioning

confidence: 99%

Transformation of M/A Constituents during Tempering and Its Effects on Impact Toughness of Weld Metals for X80 Hot Bends

Qiao

Han

Xiao

et al. 2019

Advances in Materials Science and Engineering

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Impact toughness of the weld metal is one of the important factors affecting the quality of hot bends, which is strongly dependent on the microstructure transformation during hot bending and tempering. In this study, three kinds of weld metals with different Ni contents were selected, and then the effects of tempering temperature on the microstructure impact toughness of weld metals for hot bends were investigated by simulation conducted on a Gleeble-3500 thermal simulator. The results show that the nonmetallic inclusion particles in weld metals can become the nuclear core of acicular ferrite like in as-welded metal. So, the overlapping acicular ferrite microstructure is obtained in the weld metal after direct cooling from the reheating temperature. During tempering, the overlapping acicular ferrite microstructure is degenerated, and martensite/austenite (M/A) constituents in the acicular ferrite microstructure decompose into ferrites and carbides. The resulting carbide particles mainly distribute along the acicular ferrite grain boundaries. With the increase of the tempering temperature, the carbide particles coarsen, which decreases the impact toughness of the weld metal of hot bends. Addition of Ni to weld metals can refine the acicular ferrite and improve the impact toughness.

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Section: Introductionmentioning

confidence: 99%

Transformation of M/A Constituents during Tempering and Its Effects on Impact Toughness of Weld Metals for X80 Hot Bends

Qiao

Han

Xiao

et al. 2019

Advances in Materials Science and Engineering

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“…In [24], the authors evaluated the mechanical properties of API 5L X80 pipes and concluded that the mechanical properties from different suppliers have a strong correlation with EC, especially TS and toughness. In the case of the steels used in this study, sample 3 came from a batch that presented ECPcm values slightly higher than the batch that originated sample 4.…”

Section: Resultsmentioning

confidence: 99%

Laminação Termo-Mecânica Visando a Obtenção De Um Aço Api 5l Grau X80 No Laminador De Chapas Grossas Da Gerdau - Efeitos Das Estratégias De Laminação

Abreu

2023

ABM Proceedings

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The oil and gas industry has been demanding high-performance steels, with increasingly competitive projects with requirements for safe application and high responsibility. Despite advances in the controlled rolling of microalloyed materials followed by accelerated cooling, it is still a challenge to obtain these products in rolling mills with the characteristics of the single-stand reversible rolling mill followed by accelerated cooling, at the Gerdau in Ouro Branco. This study aimed to develop the production of heavy plates, mostly bainitic, to meet API 5L X80 Standard, evaluating the effects of rolling parameters and austenite conditioning on the microstructure and mechanical properties. For this, chemical composition, processing temperatures, and average deformations were specified, through mathematical models and bibliographical references. Four rolling conditions were performed, compared and critically analyzed. In addition, microstructural and mechanical characterizations were carried out using the techniques: OM, SEM, tensile tests, Charpy impact tests and hardness tests to verify compliance with the API 5L Standard. The results indicated that the austenite conditioning strongly influenced the microstructure and the mechanical properties. In addition, an optimized route to produce the material was determined considering the specificities of the used rolling mill.

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“…With the rapid increase in demand for clean energy, such as natural gas, long-distance gas transportation pipelines are developing towards larger diameters and higher operating pressures to maximize transport efficiency, promoting the rapid development of high-strength pipeline steel. Thus, high-strength X80 grade steels have been applied in high-throughput long-distance gas transportation pipelines [ 1 , 2 , 3 ]. Although the traditional acicular ferrite (or low-carbon bainite) high-strength pipeline steels have good strength, toughness, and weldability balance, their plasticity does not meet the requirements of long-distance gas transportation pipelines to prevent deformation collapse caused by geological and ocean current movement in hazardous geological areas.…”

Section: Introductionmentioning

confidence: 99%

Effect of Bainite to Ferrite Yield Strength Ratio on the Deformability of Mesostructures for Ferrite/Bainite Dual-Phase Steels

et al. 2021

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The strength and plasticity balance of F/B dual-phase X80 pipeline steels strongly depends on deformation compatibility between the soft phase of ferrite and the hard phase of bainite; thus, the tensile strength of ferrite and bainite, as non-negligible factors affecting the deformation compatibility, should be considered first. In this purely theoretical paper, an abstract representative volume elements (RVE) model was developed, based on the mesostructure of an F/B dual-phase X80 pipeline steel. The effect of the yield strength difference between bainite and ferrite on tensile properties and the strain hardening behaviors of the mesostructure was studied. The results show that deformation first occurs in ferrite, and strain and stress localize in ferrite prior to bainite. In the modified Crussard-Jaoul (C-J) analysis, as the yield strength ratio of bainite to ferrite (σy,B/σy,F) increases, the transition strain associated with the deformation transformation from ferrite soft phase deformation to uniform deformation of ferrite and bainite increases. Meanwhile, as the uncoordinated deformation of ferrite and bainite is enhanced, the strain localization factor (SLF) increases, especially the local strain concentration. Consequently, the yield, tensile strength, and yield ratio (yield strength/tensile strength) increase with the increase in σy,B/σy,F. Inversely, the strain hardening exponent and uniform elongation decrease.

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Mechanical Properties of High-Nb X80 Steel Weld Pipes for the Second West-to-East Gas Transmission Pipeline Project

Cited by 9 publications

References 17 publications

Transformation of M/A Constituents during Tempering and Its Effects on Impact Toughness of Weld Metals for X80 Hot Bends

Transformation of M/A Constituents during Tempering and Its Effects on Impact Toughness of Weld Metals for X80 Hot Bends

Laminação Termo-Mecânica Visando a Obtenção De Um Aço Api 5l Grau X80 No Laminador De Chapas Grossas Da Gerdau - Efeitos Das Estratégias De Laminação

Effect of Bainite to Ferrite Yield Strength Ratio on the Deformability of Mesostructures for Ferrite/Bainite Dual-Phase Steels

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