TY - JOUR
T1 - A new strategy for developing a Nb microalloyed fire-resistant steel
T2 - Effects of boron and cooling rate
AU - Ferreira, A. M.
AU - Ariza, E. A.
AU - Bauri, L. F.
AU - Gomes, P. M.C.D.
AU - Carvalho, F. M.S.B.
AU - Masoumi, M.
AU - Poplawsky, J. D.
AU - Goldenstein, H.
AU - Tschiptschin, A. P.
N1 - Publisher Copyright:
© 2024 The Authors
PY - 2024/11/1
Y1 - 2024/11/1
N2 - This study investigates the correlation among cooling rates, boron addition, and their subsequent effects on the microstructure and mechanical properties of niobium microalloyed steels, specifically with an intent to develop new fire-resistant steels. Slower cooling rates enhanced the ferrite transformation and (Nb,Ti)C precipitation, promoting a shift toward an equilibrium-phase microstructure. A boron addition of 30 ppm was sufficient to increase the fire resistance of niobium microalloyed steels when slowly cooled after thermocontrolled rolling. At rapid cooling rate boron induced the formation of upper bainite. Boron is mainly segregated at the interface of (Nb,Ti)C precipitates, possibly hindering the coarsening kinetics of nanosized carbides and contributing to the maintenance of a high yield strength during fire exposure simulations. The boron addition promoted a ratio between yield strength at 600 °C and room temperature greater than 66%., boron also shifted the strain-temperature curve to higher temperatures in transient tensile tests. These findings contribute to the potential use of boron additions in advancing cost-effective, high-performance, fire-resistant steel development, highlighting the central role of microstructural control and optimized thermomechanical treatment.
AB - This study investigates the correlation among cooling rates, boron addition, and their subsequent effects on the microstructure and mechanical properties of niobium microalloyed steels, specifically with an intent to develop new fire-resistant steels. Slower cooling rates enhanced the ferrite transformation and (Nb,Ti)C precipitation, promoting a shift toward an equilibrium-phase microstructure. A boron addition of 30 ppm was sufficient to increase the fire resistance of niobium microalloyed steels when slowly cooled after thermocontrolled rolling. At rapid cooling rate boron induced the formation of upper bainite. Boron is mainly segregated at the interface of (Nb,Ti)C precipitates, possibly hindering the coarsening kinetics of nanosized carbides and contributing to the maintenance of a high yield strength during fire exposure simulations. The boron addition promoted a ratio between yield strength at 600 °C and room temperature greater than 66%., boron also shifted the strain-temperature curve to higher temperatures in transient tensile tests. These findings contribute to the potential use of boron additions in advancing cost-effective, high-performance, fire-resistant steel development, highlighting the central role of microstructural control and optimized thermomechanical treatment.
KW - Fire simulation tests
KW - Fire-resistant steels
KW - Nanoprecipitates
KW - Niobium microalloyed steels
UR - http://www.scopus.com/inward/record.url?scp=85205135842&partnerID=8YFLogxK
U2 - 10.1016/j.jmrt.2024.09.150
DO - 10.1016/j.jmrt.2024.09.150
M3 - Article
AN - SCOPUS:85205135842
SN - 2238-7854
VL - 33
SP - 2365
EP - 2376
JO - Journal of Materials Research and Technology
JF - Journal of Materials Research and Technology
ER -