Effect of welding heat input on microstructural evolution, precipitation behavior and resultant properties of the simulated CGHAZ in high-N V-alloyed steel

Xin, Wenbin; Luo, Guoping; Wang, Ruifen; Meng, Qingyong; Xian, Shangtong

doi:10.1016/j.matchar.2020.110201

Cited by 31 publications

(16 citation statements)

References 38 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The specimens were subjected to welding thermal cycles with 20 kJ/cm heat inputs and different peak temperatures (T P ). Based on the correlation between heat inputs (E) and t 8/5 , the corresponding t 8/5 for the 20 kJ/cm heat inputs was 21 s [ 10 , 17 ]. Simulated welding thermal cycles of the experimental steel HAZ are shown in Figure 2 .…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Effect of Welding Peak Temperature on Microstructure and Impact Toughness of Heat-Affected Zone of Q690 High Strength Bridge Steel

et al. 2021

View full text Add to dashboard Cite

The effect of peak temperature (TP) on the microstructure and impact toughness of the welding heat-affected zone (HAZ) of Q690 high-strength bridge steel was studied using a Gleeble-3500 thermal simulation testing machine. The results show that the microstructure of the inter critical heat-affected zone (ICHAZ) was ferrite and bainite. The microstructure of fine grain heat-affected zone (FGHAZ) and coarse grain heat-affected zone (CGHAZ) was lath bainite (LB) LB, lath martensite (LM), and granular bainite (GB), but the microstructure of FGHAZ was finer. With the increase in peak temperature, the content of LB and GB decreased, the content of LM increased, and the lath bundles of LM and LB gradually became coarser. With the increase in peak temperature, the grain size of the original austenite increased significantly, and the impact toughness decreased significantly. When the peak temperature was 800 °C, the toughness was the best. For CGHAZ, the peak temperature should be less than 1200 °C to avoid excessive growth of grain and reduction of mechanical property.

show abstract

Section: Methodsmentioning

confidence: 99%

“…Recent research has focused on the effect of heat input on the microstructure and properties of HAZ [ 5 , 8 , 9 , 10 ]. In general, welding heat input can be related to Δt 8/5 .…”

Section: Introductionmentioning

confidence: 99%

Effect of Welding Peak Temperature on Microstructure and Impact Toughness of Heat-Affected Zone of Q690 High Strength Bridge Steel

et al. 2021

View full text Add to dashboard Cite

show abstract

“…The submicron-scale complex precipitates, (Ti,V)(C,N) and (V,Ti)(C,N), with Ti(C,N) inside and V(C,N) on the surface, can form a certain orientation relationship with ferrite: (001) precipitate //(001) ferrite , (100) precipitate //(110) ferrite [32]. Zhang et al observed the orientation relationship (001) α // (110) V(C,N) using HRTEM [30]. Moreover, precipitates between 0.25-0.8 µm support ferrite nucleation very well [33,34].…”

Section: Effects Of Increasing Heat Input On Simulated Cghaz Microstructuresmentioning

confidence: 99%

“…To refine the microstructure of CGHAZ under a high heat input, N micro-alloying provides a good design idea. Zhang et al [30] revealed that the optimum impact toughness occurred using a high heat input; the increased formation of AF and HAGB remedied the detrimental effects caused by the coarsened PAG and M/A constituent. However, one noteworthy observation is that impact toughness increased along with increases in heat input in the low-carbon N-enhanced steel, though the details are unclear.…”

Section: Introductionmentioning

confidence: 99%

Effect of Welding Heat Input on Microstructure and Impact Toughness in the Simulated CGHAZ of Low Carbon Mo-V-Ti-N-B Steel

Qiao

Fan

Shi

et al. 2021

Metals

View full text Add to dashboard Cite

Welding thermal cycles with heat inputs ranging from 25 to 75 kJ/cm were performed on a Gleeble 3500. The impact energy improved significantly (from 10 to 112 J), whereas the simulated coarse-grain heat-affected zone (CGHAZ) microstructure changed from lath bainite ferrite (LBF) and granular bainite ferrite (GBF) + martensite/austenite (M/A) to acicular ferrite (AF) + polygonal ferrite (PF) + M/A as the heat input increased. Simultaneously, the mean coarse precipitate sizes and the degree of V(C,N) enrichment on the precipitate surface increased, which provided favorable conditions for intragranular ferrite nucleation. The Ar3 of CGHAZ increased from 593 °C to 793 °C with increasing heat inputs; the longer high-temperature residence time inhibited the bainite transformation and promoted the ferrite transformation. As a result, acicular ferrite increased and bainite decreased in the CGHAZ. The CGHAZ microstructure was refined for the acicular ferrite segmentation of the prior austenite, and the microstructure mean equivalent diameter (MED) in the CGHAZ decreased from 7.6 µm to 4.2 µm; the densities of grain boundaries higher than 15° increased from 20.3% to 45.5% and significantly increased the impact toughness. The correlation of heat input, microstructure, and impact toughness was investigated in detail. These results may provide new ideas for the development of high welding heat input multiphase steels.

show abstract

“…As the heat input increases, the small VN may dissolve and then precipitate on the dissolved particles during cooling, coarsening the particles and reducing the barrier for the particles to promote the formation of acicular ferrite. Zhang et al [12] revealed that the optimum impact toughness is obtained at a high heat input (t 8/5 =180 s) for the increased formation of intragranular ferrite, especially AF, and high angle grain boundry. The interesting phenomenon that AF increases as the increase of heat input in the low-carbon micro-alloyed steel remains unclear in detail.…”

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 welding heat input on microstructural evolution, precipitation behavior and resultant properties of the simulated CGHAZ in high-N V-alloyed steel

Cited by 31 publications

References 38 publications

Effect of Welding Peak Temperature on Microstructure and Impact Toughness of Heat-Affected Zone of Q690 High Strength Bridge Steel

Effect of Welding Peak Temperature on Microstructure and Impact Toughness of Heat-Affected Zone of Q690 High Strength Bridge Steel

Effect of Welding Heat Input on Microstructure and Impact Toughness in the Simulated CGHAZ of Low Carbon Mo-V-Ti-N-B 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