Hot ductility behavior of boron microalloyed steels

López-Chipres, E.; Mejı́a, I.; Maldonado, C.; Bedolla-Jacuinde, A.; Cabrera, J.M.

doi:10.1016/j.msea.2007.01.098

Cited by 76 publications

(77 citation statements)

References 36 publications

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“…Boron additions can improve the hot ductility as shown by the work of Loprez-Chipres et al [133]. They examined a low C, 0.04%C, 0.025%Al steel with 0.008%N and found that the hot ductility markedly improved as the B/N ratio increased from 0.33 to 1.25, (the stoichiometric ratio for BN is 0.8); the minimum depth at 800 o C increasing from an RA value of 45 to 70%, as shown in Fig.2.53.…”

Section: Boronmentioning

confidence: 92%

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Hot ductility of TWIP steels

Kang

Tuling

Banerjee

et al. 2011

Materials Science and Technology

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The hot ductility of twin induced plasticity (TWIP), 0·6 wt-C steels containing 18–22 wt-Mn with N levels in the range 0·005–0·023 wt- and the Al additions either low (<0·05 wt-) or high (1·5 wt-) has been examined. Little change in ductility occurred in the temperature range 1100–650°C as the structure was always fully austenitic. Ductility was generally poor (<40), reduction of area values, the best ductility at the higher Al level being given by the steel with the lowest N and S levels. Because the steel is fully austenitic, the ductility is solely dependent on that for unrecrystallised austenite. Therefore, to avoid transverse cracking the volume of second phase particles should be kept to a minimum, i.e. the N should be low to reduce the amount of AlN that can be precipitated out and the S level should be as low as possible to limit the amount of MnS inclusions. Metallographic and TEM studies were carried out and the poor ductility was found to be due to extensive precipitation of AlN at the austenite grain boundaries. Increasing the cooling rate from the melting point to the test temperature from 60 to 180°C min−1 or introducing an undercooling step both led to even worse ductility.

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Section: Boronmentioning

confidence: 92%

“…At low temperatures (700℃) where recrystallization is absent, recovery of hot ductility is related to a high volume fraction of ferrite so that strain concentration does not occur [107]. Fig.2.53 Hot ductility curves for boron microalloyed steels (RA, reduction of area) [133].…”

Section: Boronmentioning

confidence: 99%

Hot ductility of TWIP steels

Kang

Tuling

Banerjee

et al. 2011

Materials Science and Technology

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“…[6][7][8] Addition of B to plain carbon steel improves hot ductility in the austenite single-phase region because solute B atoms that segregate to grain boundaries can occupy vacancies and thus prevent formation and propagation of microcracks at grain boundaries. 9,10) However, in B-bearing steel, transverse cracking on the slab surface easily occurs during continuous casting (CC) process because of poor hot ductility at temperatures of 700-1 000°C, possibly due to formation of Boron Nitride (BN) at austenite (g) grain boundaries. 11) The diffusion coefficient of B in low carbon steel is on the order of 10 Ϫ10 m 2 /s at ϳ1 200°C.…”

Section: Introductionmentioning

confidence: 99%

Effect of Thermal Cycle and Nitrogen Content on the Hot Ductility of Boron-bearing Steel

et al. 2010

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“…As temperature increases, some fluctuations are observed in the flow curves for all examined TWIP steels. Such fluctuations are evidence of DRX, which is usually characterized either by a sudden drop or by oscillations in the flow curve [33]. On the contrary, the tensile elongation to fracture decreases as temperature increases.…”

Section: Tensile Behaviormentioning

confidence: 99%

“…In fact, boron has been added to modern low carbon microalloyed steels, i.e., advanced high-strength steels (AHSS), to reduce the use of more expensive alloying elements, which improves the hot flow behavior of steel in a similar or higher level than carbon does [32][33][34][35][36]. Such studies indicate that the improved hot ductility obtained after boron additions can be associated with boron segregation to austenite grain boundaries, phenomenon that increases grain boundary cohesion.…”

Section: Introductionmentioning

confidence: 99%

Effect of Ti and B microadditions on the hot ductility behavior of a High-Mn austenitic Fe–23Mn–1.5Al–1.3Si–0.5C TWIP steel

Mejı́a

Salas-Reyes

Calvo

et al. 2015

Materials Science and Engineering: A

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a b s t r a c tThis research work studies the effect of combined Ti and B microadditions and the solidification route on the hot ductility behavior of a high-Mn austenitic Twinning Induced Plasticity (TWIP) steel. For this purpose, uniaxial hot tensile tests were carried out at different temperatures between 700 and 1100°C under a constant strain rate of 10. The hot ductility was determined by measuring the reduction of transverse area (%RA) after specimen rupture. Characterization was performed by SEM-EBSD and TEM techniques in order to identify the relationship between microstructural features and cracking phenomena. Results indicate that the early occurrence of dynamic recrystallization (DRX) at the intermediate temperature range (800-900°C) is the favorable mechanism that enhances the ductility, achieving RA values up to 82%. These high RA values are discussed in terms of the boron effect on the improvement of the grain-boundaries cohesion through non-equilibrium segregation, and Ti(C,N) precipitation, which reduces the formation of harmful precipitates such as BN and AlN. Additionally, the Fe 23 (B,C) 6 and B 4 C compounds were identified, which are less detrimental to hot ductility than boron-nitride compounds. Finally, the fracture surfaces of the present TWIP steels in the temperature range of the highest ductility indicate that the failure mode is of the ductile type as evidenced by the presence of many dimples.

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Hot ductility behavior of boron microalloyed steels

Cited by 76 publications

References 36 publications

Hot ductility of TWIP steels

Hot ductility of TWIP steels

Effect of Thermal Cycle and Nitrogen Content on the Hot Ductility of Boron-bearing Steel

Effect of Ti and B microadditions on the hot ductility behavior of a High-Mn austenitic Fe–23Mn–1.5Al–1.3Si–0.5C TWIP steel

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