Effect of heat inputs on microstructure and mechanical properties in CGHAZ of BWELDY960Q steel

Qin, Hongbo; Guo, Yong; Wang, L.; Liang, Peng-cheng; Shi, Yantao; Cui, Yunjiang

doi:10.4149/km_2019_5_355

“…The size of M/A islands is a key factor for the microcracks formation induced by M/A islands (Moeinifar et al, 2011;Jorge et al, 2021). With the increase in the size of M/A islands, the exerted load for inducing the microcrack is decreased (Lan et al, 2014;Qin et al, 2019;Cui et al, 2020). On the other hand, the literatures (Li et al, 2011;Lan et al, 2012;Li et al, 2015) documented that fine-sized M/A islands do not impair the toughness of metal.…”

Section: Resultsmentioning

confidence: 99%

Effect of boron treatment on the microstructure and toughness of Ti-containing steel weld metals

Cui

¹

,

Wang²

2022

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Ti-containing steel weld metals with boron addition contents of 0-85 ppm were prepared, and their microstructural characteristics as well as the impact toughness were investigated. The results show that in these microstructures, compared to the weld metal without boron, the addition of 22-39 ppm boron results in a remarkable increase in the amount of acicular ferrite at the expense of grain boundary ferrite, idiomorphic ferrite and side-plate ferrite. However, with a further increase in the boron content up to 61-85 ppm, the bainitic ferrite is formed, accompanied with a drop in the amount of acicular ferrite. In the acicular ferrite, the size of martensite-austenite (M/A) islands is much smaller, and the amount is much lower than those found in the bainitic ferrite. In the case of the weld metals primarily composed of acicular ferrite, during the fracture of the impact specimens, the crack propagation path is more bent in comparison with the weld metals with large amounts of grain boundary ferrite, idiomorphic ferrite, side-plate ferrite or bainitic ferrite, which that the presence of acicular ferrite improves the toughness of the weld metals. The coarse martensite-austenite islands readily induce micro-cracks at the interface between martensite-austenite islands and ferrite matrix, deteriorating the toughness. The weld metals with B contents of 22-39 ppm exhibit outstanding impact toughness because of high amount of acicular ferrite, accompanied with fine martensite-austenite islands.

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“…The size of M/A islands is a key factor for the microcracks formation induced by M/A islands [31,32]. With the increase in the size of M/A islands, the exerted load for inducing the microcrack is decreased [33][34][35]. On the other hand, the literature [36][37][38] documented that fine-sized M/A islands did not impair the toughness of metal.…”

Section: Resultsmentioning

confidence: 99%

Effect of boron addition on microstructure and toughness of Ti-containing weld metals

Wang¹,

Li²

2022

KM

0

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Ti-containing weld metals with boron (B) contents of 0-85 ppm were prepared, and the microstructural characteristics and impact toughness of weld metals were investigated. The results show that compared with the weld metal without B, in the weld metal with 22 ppm B, the fraction of acicular ferrite (AF) is increased from 26 to 76 %, accompanied by a remarkable decrease in the contents of pro eutectoid ferrite (PF), grain boundary ferrite (GBF) and sideplate ferrite (SPF). In the 39 ppm B weld metal, the microstructure basically consists of AF. However, a further increase in the B content up to 61 ppm decreases the fraction of AF to 66 % due to the formation of bainitic ferrite (BF). For the weld metal with 85 ppm B, the microstructure is wholly composed of BF. The size of martensite-austenite (M/A) islands distributed between AF plates is much smaller, and the amount is much lower than this between BF plates. In the case of the weld metals primarily composed of AF, during fracture of impact specimens, crack propagation deflects much more frequently in comparison to the weld metals with large amounts of PF, GBF and SPF, or BF, which improves the toughness of weld metals. The coarse M/A islands readily induce microcracks at the interface between M/A islands and the ferrite matrix, deteriorating the toughness. The weld metals with B contents of 22 and 39 ppm exhibit outstanding impact toughness because of a high fraction of AF accompanied by fine M/A islands.

show abstract

Effect of boron addition on microstructure and toughness of Ti-containing weld metals

Wang¹,

Li²

2022

KM

0

View full text Add to dashboard Cite

Ti-containing weld metals with boron (B) contents of 0-85 ppm were prepared, and the microstructural characteristics and impact toughness of weld metals were investigated. The results show that compared with the weld metal without B, in the weld metal with 22 ppm B, the fraction of acicular ferrite (AF) is increased from 26 to 76 %, accompanied by a remarkable decrease in the contents of pro eutectoid ferrite (PF), grain boundary ferrite (GBF) and sideplate ferrite (SPF). In the 39 ppm B weld metal, the microstructure basically consists of AF. However, a further increase in the B content up to 61 ppm decreases the fraction of AF to 66 % due to the formation of bainitic ferrite (BF). For the weld metal with 85 ppm B, the microstructure is wholly composed of BF. The size of martensite-austenite (M/A) islands distributed between AF plates is much smaller, and the amount is much lower than this between BF plates. In the case of the weld metals primarily composed of AF, during fracture of impact specimens, crack propagation deflects much more frequently in comparison to the weld metals with large amounts of PF, GBF and SPF, or BF, which improves the toughness of weld metals. The coarse M/A islands readily induce microcracks at the interface between M/A islands and the ferrite matrix, deteriorating the toughness. The weld metals with B contents of 22 and 39 ppm exhibit outstanding impact toughness because of a high fraction of AF accompanied by fine M/A islands.

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Effect of heat inputs on microstructure and mechanical properties in CGHAZ of BWELDY960Q steel

Cited by 3 publications

References 32 publications

Effect of boron treatment on the microstructure and toughness of Ti-containing steel weld metals

Effect of boron treatment on the microstructure and toughness of Ti-containing steel weld metals

Effect of boron addition on microstructure and toughness of Ti-containing weld metals

Effect of boron addition on microstructure and toughness of Ti-containing weld metals

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