Effect of Ti content on the inclusions, microstructure and fracture mechanism of X100 pipeline steel laser-MAG hybrid welds

Qi, Xiaonan; Wang, Xiaonan; Di, Hongshuang; Shen, Xinjun; Liu, Zhenguang; Huan, Pengcheng; Чэн, Лонг

doi:10.1016/j.msea.2021.142207

Cited by 33 publications

(7 citation statements)

References 32 publications

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“…[ 28 ] In this case, the higher the boundary energy of the martensite packet encountered by the secondary crack, the larger the crack deflection angle, and the higher the energy consumed. [ 29 ] Thus, the martensite packet hindered crack propagation to improve the strength.…”

Section: Resultsmentioning

confidence: 99%

Effect of Quenching and Tempering Temperatures on Microstructure and Properties of Ultrahigh Strength Cast Steel

Zhou

Zhao

Dong

et al. 2022

steel research int.

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Low‐alloy cast steel with ultrahigh strength is produced by a combination of normalizing and reheating, followed by water quenching and high‐temperature tempering. The cast steel quenched at 1000 °C for 30 min and tempered at 550 °C for 120 min exhibits superior tensile ductility. More precisely, the tensile strength is 1683.5 MPa, yield strength is 1635.3 MPa, elongation is 12.0%, and microhardness is 500.3 HV. The microstructure is composed of martensite lath + ferrite + M23C6 carbide. The strengthening mechanisms of the steel are mainly precipitation, grain refinement, and dislocation strengthening. When the quenching temperature is increased from 950 to 1000 °C, the M3C carbides precipitated between the martensite lath are transformed from short rod‐like to spherical shapes, which improves the plasticity of the steel. When the tempering temperature is increased from 550 to 630 °C, the number and size of the carbides also increase. The M23C6 carbides interact with the dislocations. M23C6 carbides play a crucial role in the precipitation strengthening and efficiently improve the strength of the steel. The fracture is changed from a mixed ductile and brittle fracture to a ductile fracture.

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Section: Resultsmentioning

confidence: 99%

Effect of Quenching and Tempering Temperatures on Microstructure and Properties of Ultrahigh Strength Cast Steel

Zhou

Zhao

Dong

et al. 2022

steel research int.

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show abstract

“…[7,8] This interlocking structure can slice the original grain, and its staggered structure and high-angle grain boundary can prevent crack propagation, thus improving the mechanical properties of the material, especially the toughness. [9][10][11][12][13][14]…”

Section: Introductionmentioning

confidence: 99%

Review of Research on Titanium Oxides in Low‐Carbon Steel

Lei,

Zhang,

et al. 2023

steel research int.

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Titanium oxides, which act as nuclei for intragranular ferrite, are common inclusions in low carbon steel. The interlocking structure of intragranular ferrite greatly improves the mechanical properties of low carbon steel. To make the best use of this kind of oxide, we reviewed the types, sizes and distribution properties of effective titanium oxides that can promote intragranular ferrite nucleation. We summarized the control techniques of titanium oxides as follows: (1) Ti2O3 is one of the most effective of the common titanium oxides, followed by TiO and TiO2. The type of titanium oxide can be affected by controlling the Ti/O mass ratio in molten steel. (2) Titanium oxide with the size range of 0.4‐4 μm can effectively promote the nucleation of IGF or IAF, among them, titanium oxide about 1 μm is the most beneficial to IAF nucleation. (3) In order to obtain the titanium oxides with effective size, the precipitation of titanium oxides should be controlled during the solidification process, and this process can be achieved in the existing rapid solidification technology. Under the same conditions, the higher solidification rate can obtain finer titanium oxide.This article is protected by copyright. All rights reserved.

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“…These aspects have restricted the manufacture of offshore platform. To achieve a better welded joint, laser hybrid welding (LHW) has obtained increasing attention for joining steel plates because of its excellent industrial prospects [3][4][5]. LHW can be as a combination of arc and laser welding techniques, which can produce a narrow, deep joint by Available online at http://link.springer.com/journal/40195.…”

Section: Introductionmentioning

confidence: 99%

“…In other words, impact toughness is still one of the key problems of LHW. Because it's extremely rapid cooling rate may cause the generation of martensite and welding defects, such as pores and cracks [4,13]. However, for the comparative study of SAW and LHW, there is still little research on the fine characterization of microstructure in welded joint and its relationship with impact toughness, though it is indeed one of the research hotspot.…”

Section: Introductionmentioning

confidence: 99%

Microstructure Evolution of Heat-Affected Zone in Submerged Arc Welding and Laser Hybrid Welding of 690 MPa High Strength Steel and its Relationship with Ductile–Brittle Transition Temperature

Wang

Xie

et al. 2022

Acta Metall. Sin. (Engl. Lett.)

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The comparative study of submerged arc welding (SAW) and laser hybrid welding (LHW) was carried out for a 690 MPa high strength steel with thickness of 20 mm. Microstructure and ductile-brittle transition temperature (DBTT) evolution in welded zone were elucidated from the aspect of crystallographic structure, particularly, digitization and visualization of 24 variants. The impact toughness of each micro zone in LHW joint is better than that of SAW, in which the DBTT of equivalent fusion line and heat-affected zone (HAZ) can reach − 70 and − 80 °C, while that of SAW is only − 50 °C. LHW technology induces narrowing of the HAZ and refining of the microstructure obtained in weld metal and HAZ. Meanwhile, the austenite grain size and transformation driving force in the coarse grained heat-affected zone (CGHAZ) are reduced and increased, respectively. It makes variant selection mechanism occurring in CGHAZ of LHW dominate by close-packed plane grouping, which promotes lath bainite formation with high density of high angle grain boundary, especially block boundary dominated by V1/V2 pair. While for SAW, the lower transformation driving force inferred from the large amount of retained austenite in CGHAZ induces Bain grouping of variants, and thus triggers the brittle crack propagating straightly in granular bainite, resulting in lower impact toughness and higher DBTT.

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Effect of Ti content on the inclusions, microstructure and fracture mechanism of X100 pipeline steel laser-MAG hybrid welds

Cited by 33 publications

References 32 publications

Effect of Quenching and Tempering Temperatures on Microstructure and Properties of Ultrahigh Strength Cast Steel

Effect of Quenching and Tempering Temperatures on Microstructure and Properties of Ultrahigh Strength Cast Steel

Review of Research on Titanium Oxides in Low‐Carbon Steel

Microstructure Evolution of Heat-Affected Zone in Submerged Arc Welding and Laser Hybrid Welding of 690 MPa High Strength Steel and its Relationship with Ductile–Brittle Transition Temperature

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