ISIJ International
Online ISSN : 1347-5460
Print ISSN : 0915-1559
ISSN-L : 0915-1559
Regular Article
Ferrite Formation above the Ae3 Temperature during the Torsion Simulation of Strip Rolling
Clodualdo Aranas Jr.Samuel Filgueiras RodriguesRupanjit GrewalJohn Joseph Jonas
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2015 Volume 55 Issue 11 Pages 2426-2434


Torsion simulations of 7-pass strip rolling were carried out on a 0.06%C-0.3%Mn-0.01%Si and a 0.11%C-1.0%Mn-0.11%Si-0.03%Al-0.034%Nb steel using pass strains of 0.4 applied at 1 s−1. The deformations were imposed isothermally at 910°C and 930°C for the C–Mn and the Nb microalloyed steel, respectively. The flow curve levels decreased from pass to pass as a result of softening by both dynamic transformation (DT) and dynamic recrystallization (DRX). The application of double differentiation to the stress-strain curves led to average critical strains for the initiation of DT and DRX of about 0.06 and 0.11, respectively. Optical microscopy revealed that the volume fraction of DT ferrite increased continuously right up to the last pass. The fraction of DT ferrite formed and retained was significantly higher when short interpass times were used. Comparison of the behaviors of the C–Mn and Nb steels indicates that Nb addition retards both the forward as well as the reverse transformation.

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© 2015 by The Iron and Steel Institute of Japan
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