Abstract
Ultra-fast cooling (UFC) has been increasingly applied in industry, but accompanying with great changes of rolling strategy. It is therefore of importance to evaluate the characteristics of steels produced by UFC as compared to those processed by conventional accelerated cooling (ACQ. The present study examines the microstructure through thickness and centerline segregation of solute elements between UFC and ACC steels, both of which were rolled at a final rolling temperature at around non-recrystallized temperature. UFC steel showed the pronounced microstructural transition from lath-type bainite with Widmanstätten ferrite at subsurface to acicular ferrite in an average size of ~5 µm dispersed with degenerate pearlite in the interior. In contrast, ACC steel had the homogeneous microstructure through the thickness, which was distinguished with coarser polygonal ferrite grains and pearlite nodules. Moreover, the centerline segregation was significantly suppressed by applying UFC at a higher cooling rate of 40 K/s compared to 17K/s for ACC steel. The significant differences in the microstructure and centerline segregation caused by various cooling rate is discussed from the view of γ→α transformation.
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Ye, Q., Liu, Z., Wang, G. (2016). Effect of Cooling Rate on Microstructure and Centerline Segregation of a High-Strength Steel for Shipbuilding. In: HSLA Steels 2015, Microalloying 2015 & Offshore Engineering Steels 2015. Springer, Cham. https://doi.org/10.1007/978-3-319-48767-0_41
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DOI: https://doi.org/10.1007/978-3-319-48767-0_41
Publisher Name: Springer, Cham
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