Effect of boron on intragranular ferrite nucleation mechanism in coarse grain heat-affected zone of high-nitrogen steel

Shi, Zhongran; Wang, Jiaji; Chai, Xiaoyan; Wang, Shihong; Chen, Gang; Wang, Ruizhen

doi:10.1016/j.matlet.2019.126819

Cited by 13 publications

(14 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…From Figure 6 , the sizes of the prior austenite grain of the B1, B2, B3 weld metals were in the range of 60–200, 40–140, and 40–120 μm, respectively. A large number of studies have shown that the addition of boron usually causes the redistribution of grain boundary energy caused by boron segregation [ 15 ], reduces the number of ferrite heterogeneity nucleation [ 7 ], causes boron segregation on the prior austenite grain boundary [ 23 , 24 ], and delays the transformation process from austenite to ferrite during cooling [ 21 , 25 ]. In our study, although the distribution of B could not be identified, the refinement of grain size could be found because of the addition of B content.…”

Section: Resultsmentioning

confidence: 99%

“…Zhu et al [ 14 ] indicated that the addition of B only slightly decreased the bainite transformation temperature at low cooling rates (≤10 °C/s), whereas the combined addition of B + Nb greatly decreased the transformation temperature. Shi et al [ 15 ] found that the addition of B made the ferrite transformation temperature increase from 775 to 800 °C, the amount of polygonal ferrites increase from 63.2% to 78.6% and the ductile-to-brittle transition temperature decreases from −30 to −50 °C. Additionally, they found that the sizes of (Ti,V)(C,N)-MnS-BN, MnS-BN, Al 2 O 3 -MnS-BN, and BN contributed to IGF formation.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Effects of Boron Content on the Microstructure and Impact Toughness of 12Cr1MoVR Low-Alloy Heat-Resistant Steel Weld Metals

et al. 2021

View full text Add to dashboard Cite

The impact toughness of low-Cr heat-resistant steel weld metal is an important problem to broaden the application of low-Cr heat-resistant steel. In this study, the microstructure and impact toughness of 12Cr1MoVR low-alloy heat-resistant steel weld metals with various boron contents (B1 = 0.0028%, B2 = 0.0054%, and B3 = 0.0079%) were investigated. The microstructures of all weld metals were composed of block ferrite, carbides, and inclusions. Results indicated that with increased B content, prior austenite grain sizes decreased, and minor microstructure changes could be found. With the increase in B content from 0.0028% to 0.0054% to 0.0079%, the ductile–brittle transition temperature of the weld metals decreased from 30 to 0 to −14 °C, the toughness of weld metal increased, and the hardness slightly decreased, all of which are directly related to the refinement of prior austenite grain size because of the addition of B content. However, on the top-shelf zone, such as at the testing temperature of 80 °C, ductile fracture dominates the fracture surface; with the increase in B content, the size and density of inclusions increased gradually, which led to the decrease of the impact toughness at 80 °C when the B content was 0.0079%.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effects of Boron Content on the Microstructure and Impact Toughness of 12Cr1MoVR Low-Alloy Heat-Resistant Steel Weld Metals

et al. 2021

View full text Add to dashboard Cite

show abstract

“…In steel with low nitrogen content, B improved the low temperature toughness of the heat-affected zone (HAZ) in the following manner: (1) boron segregation in the grain boundary of austenite prevented ferrite transformation and subsequently reduced ferrite grain size [13,14]. (2) The intragranular ferrite was nucleated at the position of Fe 23 (B,C) 6 and BN [11,12,15]. (3) On the contrary, the content of solid solution nitrogen in HAZ decreased.…”

Section: Effect Of Boron On Intragranular Ferrite Nucleation In Simul...mentioning

confidence: 99%

“…Shi et al [11] researched the effect of boron on the intragranular ferrite nucleation mechanism in the CGHAZ of low-carbon V-N-Ti TMCP steel at t 8/5 180 s, and the results showed that BN formed on the undissolved precipitates to increase the nucleation potency of IGF. Funakoshi found that BN nucleated on the surface of Rare Earth Metals (REM) oxide and promoted IGF nucleation, thus improving CGHAZ toughness, and Ohno et al [12] found that a "C-poor" region was formed around Fe 23 (B,C) 6 to increase the transition temperature of ferrite, and promoted the nucleation of GBF.…”

Section: Introductionmentioning

confidence: 99%

Mechanism of BN-Promoting Acicular Ferrite Nucleation to Improve Heat-Affected Zone Toughness of V-N-Ti Microalloyed Offshore Steel

et al. 2022

Self Cite

View full text Add to dashboard Cite

This study examined the effect of boron (B) on the microstructure and toughness of the simulated coarse-grained heat-affected zone (CGHAZ) of normalized vanadium microalloyed offshore steel by using the welding thermal simulation method under different heat inputs for welding. The results showed that when t8/5 (the cooling time from 800 to 500 ∘C) increased from 14 s to 24 s, In the range of t8/5 of 24–44 s, the impact energy of the CGHAZ rose initially and then remained constant at around 125 J at −40 ∘C, and dropped to 79 J when t8/5 increased to 64 s. The particles (Ti,V)(C,N)-BN and BN contributed in the generation of acicular ferrite, which minimized the loss of CGHAZ toughness due to the presence of carbon. Furthermore, the microstructural parameters controlling CGHAZ toughness were the contents of the high misorientation grain boundaries and effective grain size at a tolerance angle of 15∘ at varied heat inputs.

show abstract

“…Fortunately, proper amount of element B is added to the steel, it can converge to the grain boundary and inhibit the formation of grain boundary ferrite [13]. Moreover, B can combine with N to form BN particles, and BN particles promote the acicular ferrite nucleus in the grain [14], which further refine the CGHAZ structure. However, the effect of heat input on the microstructure and impact toughness of CGHAZ in V-N micro-alloyed steel containing B is rarely reported.…”

Section: Introductionmentioning

confidence: 99%

Improvement of impact toughness by microstructure refinement of simulated CGHAZ through enhancing welding heat input of low carbon Mo-V-Ti-N-B steel

Fan¹,

Shi²,

Wang³

et al. 2022

Mater. Res. Express

View full text Add to dashboard Cite

Welding heat input greatly influences the microstructure and impacts the affected zone's toughness. To interpret the relationships between the welding heat input, microstructure, and low-temperature toughness of the coarse-grained heat-affected zone (CGHAZ) of Mo-V-Ti-N-B steels, welding heat cycles with different heat inputs (25–75 kJ/cm) were performed on a Gleeble 3500 simulator. Intragranular ferrite in the simulated samples subjected to different thermal cycles was characterized and quantified, and the impact energies of simulated samples were evaluated at -20 °C. Upon increasing the heat input, the intragranular ferrite content rose sharply from 4.3% to 76.0%. The V(C,N) enrichment on the precipitate surface increased the size of precipitates, providing favourable nucleation conditions for intragranular ferrite. The prior austenite grain (PAG) and martensite/austenite (M/A) constituents became rough, and the content of the M/A constituent increased while the impact energy of the CGHAZ increased. This behaviour occurred due to the formation of intragranular acicular ferrite (IGAF), which refined the microstructure of the CGHAZ. Grain refinement eliminated the negative influence of higher M/A content on the impact toughness of the CGHAZ.

show abstract

Effect of boron on intragranular ferrite nucleation mechanism in coarse grain heat-affected zone of high-nitrogen steel

Cited by 13 publications

References 15 publications

Effects of Boron Content on the Microstructure and Impact Toughness of 12Cr1MoVR Low-Alloy Heat-Resistant Steel Weld Metals

Effects of Boron Content on the Microstructure and Impact Toughness of 12Cr1MoVR Low-Alloy Heat-Resistant Steel Weld Metals

Mechanism of BN-Promoting Acicular Ferrite Nucleation to Improve Heat-Affected Zone Toughness of V-N-Ti Microalloyed Offshore Steel

Improvement of impact toughness by microstructure refinement of simulated CGHAZ through enhancing welding heat input of low carbon Mo-V-Ti-N-B steel

Contact Info

Product

Resources

About