TY - JOUR

T1 - Some Considerations on Austenite Grain Growth Kinetics from High-Temperature Laser Scanning Confocal Microscopy Observations

AU - Bernhard, Christian

AU - Kern, Maximilian

AU - Bernhard, Michael Christian

N1 - Publisher Copyright: © 2023 The Authors. Steel Research International published by Wiley-VCH GmbH.

PY - 2023/10/25

Y1 - 2023/10/25

N2 - For more than 20 years, high-temperature laser scanning confocal microscopy (HT-LSCM) has become worldwide a proven technique for observing various metallurgical phenomena in situ. HT-LSCM turns out to be a reliable and effective method for the observation of quantification austenite grain growth kinetics in steel, being highly relevant in casting and steel processing. In the present article, the measurement technique is briefly introduced followed by some basics on austenite grain growth. Finally, selected examples of recent research activities are discussed, including investigations into pure iron and the systems Fe–P, Fe–C, Fe–Al–N, and Fe–C–Nb–N. The influence of P on the grain growth kinetics is remarkable. At 1350 °C, the final grain size decreases from 255 μm in pure iron to 145 μm by adding 0.044 wt% P. In contrast, C enhances the grain growth in specific alloying ranges (0–0.30 wt%C), particularly at elevated temperatures. For a Al content of 0.025 wt% and only 50 wt ppm N, AlN loses the pinning effect above 1150 °C. In case of Nb(C,N), an elevated Nb content (0.085 wt%) provides stabilization of Nb(C,N) at 1150 °C, but at 1250 °C, no pinning of Nb(C,N) is visible anymore.

AB - For more than 20 years, high-temperature laser scanning confocal microscopy (HT-LSCM) has become worldwide a proven technique for observing various metallurgical phenomena in situ. HT-LSCM turns out to be a reliable and effective method for the observation of quantification austenite grain growth kinetics in steel, being highly relevant in casting and steel processing. In the present article, the measurement technique is briefly introduced followed by some basics on austenite grain growth. Finally, selected examples of recent research activities are discussed, including investigations into pure iron and the systems Fe–P, Fe–C, Fe–Al–N, and Fe–C–Nb–N. The influence of P on the grain growth kinetics is remarkable. At 1350 °C, the final grain size decreases from 255 μm in pure iron to 145 μm by adding 0.044 wt% P. In contrast, C enhances the grain growth in specific alloying ranges (0–0.30 wt%C), particularly at elevated temperatures. For a Al content of 0.025 wt% and only 50 wt ppm N, AlN loses the pinning effect above 1150 °C. In case of Nb(C,N), an elevated Nb content (0.085 wt%) provides stabilization of Nb(C,N) at 1150 °C, but at 1250 °C, no pinning of Nb(C,N) is visible anymore.

UR - http://www.scopus.com/inward/record.url?scp=85176594352&partnerID=8YFLogxK

U2 - 10.1002/srin.202300547

DO - 10.1002/srin.202300547

M3 - Review article

VL - ??? Stand: 12. April 2024

SP - 1

EP - 10

JO - Steel research international

JF - Steel research international

SN - 0177-4832

IS - ??? Stand: 12. April 2024

M1 - 2300547

ER -