Development of high strength ultra-heavy plate processed with gradient temperature rolling, intercritical quenching and tempering

Xie, Bao-sheng; Cai, Qingwu; Yang, Yun; Li, Gaosheng; Zhang, Ning

doi:10.1016/j.msea.2016.10.119

Cited by 35 publications

(25 citation statements)

References 23 publications

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“…[7] Xie et al developed a 60 mmthickness high-strength plate with outstanding strength homogeneity by gradient temperature rolling (GTR) process followed by intercritical quenching and tempering. [8] Wu et al applied interpass cooling technology during rough rolling (R-IPC) to process a 60 mm-thickness steel plate with excellent toughness and ductility. [9] In addition, reheat-quenching and tempering after the hot rolling process were also conducted for ultraheavy steel plates to improve the mechanical properties.…”

Section: Introductionmentioning

confidence: 99%

Superior Through‐Thickness Homogeneity of Microstructure and Mechanical Properties of Ultraheavy Steel Plate by Advanced Casting and Quenching Technologies

Wang

et al. 2021

steel research int.

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Keeping through‐thickness homogeneity of mechanical properties has been a great challenge for producing heavy gauge steel plates. Herein, a superior homogeneity of microstructure and hence strength and toughness achieved in a quenched and tempered (QT) 210 mm‐thickness steel plate produced by advanced electroslag remelting casting and roller quenching (ESR–RQ) technologies are reported. Some comparisons are made with a QT 178 mm steel plate produced by conventional mold casting and immersion quenching in the water tank (MC‐IQ). The martensite of the as‐quenched ESR–RQ steel is distributed homogeneously across the thickness with a fraction of 39% at the 1/2 thickness, remarkable higher 34% than that of MC‐IQ steel. ESR–RQ steel appears excellent comprehensive mechanical properties even for the as‐quenched samples, as well as QT samples. Comparing with the MC‐IQ steel, the Charpy impact energy at −60 °C is 150 J (278%) higher for the samples tempered at 650 °C, and the yield strength is 137 MPa (18%) higher for the samples tempered at 600 °C than those of MC‐IQ steel, respectively. The considerable improvement can be attributed to homogeneous through‐thickness microstructures, including refined prior austenite grains, effective grain size, and carbide precipitates.

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Section: Introductionmentioning

confidence: 99%

Superior Through‐Thickness Homogeneity of Microstructure and Mechanical Properties of Ultraheavy Steel Plate by Advanced Casting and Quenching Technologies

Wang

et al. 2021

steel research int.

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“…For these two key properties, they rely on the bainitic microstructure of steels [1,2,[6][7][8]. A characteristic feature of thick section components is a microstructure which is not homogeneous throughout the cross section, because during heat treatments surface areas cool faster than the interior parts [9][10][11][12][13]. Therefore, it is crucial to establish combinations of microstructures across a thick section plate which provide the best overall properties.…”

Section: Introductionmentioning

confidence: 99%

Effect of cooling rate on the microstructure and mechanical properties of a low-carbon low-alloyed steel

Wang

Cao

et al. 2021

J Mater Sci

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Heavy plate steels with bainitic microstructures are widely used in industry due to their good combination of strength and toughness. However, obtaining optimal mechanical properties is often challenging due to the complex bainitic microstructures and multiple phase constitutions caused by different cooling rates through the plate thickness. Here, both conventional and advanced microstructural characterization techniques which bridge the meso- and atomic-scales were applied to investigate how microstructure/mechanical property-relationships of a low-carbon low-alloyed steel are affected by phase transformations during continuous cooling. Mechanical tests show that the yield strength increases monotonically when cooling rates increase up to 90 K/s. The present study shows that this is associated with a decrease in the volume fraction of polygonal ferrite (PF) and a refinement of the substructure of degenerated upper bainite (DUB). The fine DUB substructures feature C-rich retained austenite/martensite-austenite (RA/M-A) constitutes which decorate the elongated micrograin boundaries in ferrite. A further increase in strength is observed when needle-shaped cementite precipitates form during water quenching within elongated micrograins. Pure martensite islands on the elongated micrograin boundaries lead to a decreased ductility. The implications for thick section plate processing are discussed based on the findings of the present work.

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“…Therefore, in our previous research, we investigated the effect of intercritical quenching-which is called lamellarizing (L) treatment-from the dual-phase region of ferrite (α) and austenite (γ) on the mechanical properties and microstructures of A707 modified steel using 50-kg test ingots [5]. L-treated steels such as structural steel and steel for very low temperatures have been studied [6][7][8][9][10][11][12][13]. On the other hand, the effects of L treatment on Cu-containing low alloy steel have not been reported.…”

Section: Introductionmentioning

confidence: 99%

“…On the other hand, the effects of L treatment on Cu-containing low alloy steel have not been reported. The strength of Cu-containing low alloy steel is improved by Cu deposited during heat treatment [2][3][4][5][6][7][8][9][10][11][12][13][14]. Therefore, for the A707 modified steel, the Cu precipitation state is very important to obtain the strength.…”

Section: Introductionmentioning

confidence: 99%

Effect of Intercritical Quenching Temperature of Cu-Containing Low Alloy Steel of Long Part Forging for Offshore Applications

2019

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In our previous study, intercritical quenching from the dual-phase region of ferrite and austenite regions, which is called lamellarizing (L) treatment, brought a clear improvement of balance between the strength and toughness of Cu-containing low alloy steel based on American Society for Testing and Materials (ASTM) A707 5L grade. Moreover, the results imply that the reverse transformation behavior during L treatment is very important in order to optimize the L treatment temperature. Hence, the purpose of this paper is to clarify the mechanism by which L treatment improves the mechanical properties in terms of reverse transformation behavior. Additionally, offshore structures require good weldability, because the structures generally have a lot of weld joints. Therefore, weldability was also investigated in this study. The investigation revealed that coarse Cu precipitates are observed in the not-transformed α phase, so the strength tendency in relation to the L treatment temperature is relevant to the area ratio of the not-transformed α phase and the transformed γ phase during L treatment. From the in situ electron back scatter diffraction (EBSD) results, it is believed to be possible to enhance the mechanical properties of Cu-containing low alloy steel by controlling the area ratio of the reverse-transformed gamma phase and selecting the appropriate L treatment temperature. Furthermore, the long part forging of Cu-containing low alloy steel has a good weldability, since the maximum hardness of the heat-affected zone (HAZ) is less than 300 HV, and the HAZ of steel has a good crack tip opening displacement (CTOD) property with less than 2.3 kJ/mm of heat input of GTAW.

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Development of high strength ultra-heavy plate processed with gradient temperature rolling, intercritical quenching and tempering

Cited by 35 publications

References 23 publications

Superior Through‐Thickness Homogeneity of Microstructure and Mechanical Properties of Ultraheavy Steel Plate by Advanced Casting and Quenching Technologies

Superior Through‐Thickness Homogeneity of Microstructure and Mechanical Properties of Ultraheavy Steel Plate by Advanced Casting and Quenching Technologies

Effect of cooling rate on the microstructure and mechanical properties of a low-carbon low-alloyed steel

Effect of Intercritical Quenching Temperature of Cu-Containing Low Alloy Steel of Long Part Forging for Offshore Applications

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