Effect of Heat Input on M-A Constituent and Toughness of Coarse Grain Heat-Affected Zone in an X100 Pipeline Steel

Wang, Xiaonan; Zhao, Yixin; Guo, Pengfei; Qi, Xiaonan; Di, Hongshuang; Zhang, Min; Chen, Changjun

doi:10.1007/s11665-019-03921-7

Cited by 16 publications

(10 citation statements)

References 25 publications

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“…Xie et al [15] studied the impact toughness of a high-strength steel that was welded using various heat inputs, and suggested that coarse martensite/austenite (M/A) constituents were the main reason for the dramatic decrease of impact toughness of the simulated CGHAZ specimens with high heat input. A similar result was obtained by Wang et al [16], they believed that fine and reduced M/A constituents in the CGHAZ were beneficial to impact toughness. However, Zhou et al [17] thought that M/A constituents cannot directly induce the impact toughness because of the low fraction of M/A constituents in their study.…”

Section: Introductionsupporting

confidence: 86%

“…Zhu et al [20] reported that the PAGS increased with increasing heat input and small PAGS was conducive to the improvement of CGHAZ toughness. According to previous studies [16,17,20], the effect of heat input on microstructure and toughness in the CGHAZ of Nb-microalloyed steels has been studied maturely. However, the correlation among heat input, microstructure evolution and toughness in the CGHAZ of V-N microalloyed pipeline steels requires further understanding.…”

Section: Introductionmentioning

confidence: 99%

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Microstructure-toughness relationship in the simulated CGHAZ of V-N microalloyed X80 pipeline steel

Wang

Gao

Song

et al. 2021

Materials Science and Technology

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The microstructure evolution, hardness and impact toughness in the simulated coarse-grained heat-affected zone (CGHAZ) of a V-N microalloyed X80 pipeline steel were studied. The results indicated that the microstructure mainly consisted of bainitic ferrite, acicular ferrite and granular bainite. The area fraction and size of M/A constituents were increased with increasing heat input. As heat input increased from 15 to 60 kJ cm−1, the hardness gradually decreased from 301 to 243 HV, and impact energy decreased from 284 to 33 J. Hardness in the CGHAZ was not sensitive to heat input. When the heat input exceeded 30 kJ cm−1, the formation of coarse granular bainite and large-sized blocky M/A constituents resulted in the deterioration of impact toughness.

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Section: Introductionsupporting

confidence: 86%

Section: Introductionmentioning

confidence: 99%

Microstructure-toughness relationship in the simulated CGHAZ of V-N microalloyed X80 pipeline steel

Wang

Gao

Song

et al. 2021

Materials Science and Technology

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“…Further, the impact fracture is usually subjected to the following processes. Under the impact load, the softer ferrite matrix preferentially undergoes initial plastic deformation, resulting in stress concentration around or at the hard brittle phase M/A constituents [44,45]. When the local stress reaches the critical fracture stress, the microcracks are initiated.…”

Section: 2mentioning

confidence: 99%

Effect of heat input on the microstructure and impact toughness of submerged arc weld metal for high-performance weathering steel

Li,

et al. 2023

Mater. Res. Express

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This study aims to elucidate the appropriate heat input (Ej) range for submerged arc welding (SAW) of high-performance weathering steel. Generally, by increasing Ej, the welding efficiency can be improved, but the toughness of the weld metal may be deteriorated. Therefore, SAW was employed to produce the weld microstructure under varying Ej from 20 to 50 kJ/cm. The Charpy V-notch impact tests were conducted at −40℃, and the weld microstructures were characterized by optical microscopy (OM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and electron backscatter diffraction (EBSD). The results indicate that the weld microstructures consist of polygonal ferrite (PF), acicular ferrite (AF), granular bainitic ferrite (GBF), and martensite/austenite (M/A) constituents under each Ej. With the increase in Ej, the proportion of PF increases, while AF and GBF are coarsened, and the area fraction (fM/A) and mean size (dM/A) of M/A constituents increase monotonically. Further, the fraction (fMTA>15°) of high-angle grain boundaries (HAGBs) with the misorientation tolerance angles (MTAs) greater than 15° is reduced, while the mean equivalent diameter (MEDMTA≥15°) of ferrite grains with HAGBs increases. Accordingly, with the increase in Ej, the impact toughness of weld degrades from 128.4 to 47.6 J. The higher degree of micro-strain concentration caused by the increase in M/A size and area leads to the formation of larger microcracks under small plastic deformation, while the reduced HAGBs have a lower inhibition effect on crack propagation. Finally, the impact toughness decreases with the increase of Ej. Overall, the findings suggest that the Ej of SAW should not exceed 40 kJ/cm in the construction of high-performance weathering steel.

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“…Rod like Cr 2 N precipitates were found in simulated HAZ specimens of weld thermal cycle with heat input of 5 kJ/cm on duplex steel exposed at 700 o C was observed by Chen and Yang 9 . Wang et al 10 reported that increasing the heat input from 8 kJ/cm to 36 kJ/cm with different t 8/5 values increases the volume fraction of precipitates from 10.07% to 16.85% respectively. Similarly, with the increase of cooling rate, the fraction of Cr 2 N precipitates decreases from 13.8% to 2.9% in HNSS is observed by Li et al 11 .…”

Section: Introductionmentioning

confidence: 99%

Thermomechanical Simulation of Heat-Affected Zones in Nickel-Free High Nitrogen Stainless Steel: Microstructural Evolution and Mechanical Property Studies

Ramalingam

Veerappagounder²,

Rangaswamy

2023

Mat. Res.

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Three different Heat Affected Zones (HAZ) in hot rolled Nickel Free High Nitrogen Stainless Steels (NFHNSS) based on three different peak temperatures were physically simulated using Gleeble Simulator to investigate microstructural evolution and structure-property correlation. Optical microscopy revealed that the austenite grains are recrystallized in the simulated heat affected zone in the peak temperature range of 750 o C to 1050 o C. Extent of recrystallization of grains and nucleation of precipitates varied with peak temperatures. TEM characterization showed the presence of Cr 2 N precipitate having an average particle size in the range of 300 nm to 395 nm in the simulated HAZ were confirmed by Selected Area Electron Diffraction (SAED) analysis. Precipitation kinetics of Cr 2 N were simulated using Thermo-Calc were found to correlate well with experimental values. Mechanical properties of specimens taken from three different HAZ were evaluated for tensile strength and hardness. Variation in strength of the different specimens has been discussed using various strengthening models. Fractography analysis was also carried out to understand the effect of peak temperature on fracture behaviour. Transition in fracture patterns in NFHNSS from ductile to mixed mode was observed for different specimens.

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Effect of Heat Input on M-A Constituent and Toughness of Coarse Grain Heat-Affected Zone in an X100 Pipeline Steel

Cited by 16 publications

References 25 publications

Microstructure-toughness relationship in the simulated CGHAZ of V-N microalloyed X80 pipeline steel

Microstructure-toughness relationship in the simulated CGHAZ of V-N microalloyed X80 pipeline steel

Effect of heat input on the microstructure and impact toughness of submerged arc weld metal for high-performance weathering steel

Thermomechanical Simulation of Heat-Affected Zones in Nickel-Free High Nitrogen Stainless Steel: Microstructural Evolution and Mechanical Property Studies

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