A Novel Approach for Controlling the Band Formation in Medium Mn Steels

Journal article (2018)

Authors

H. Farahani Novel Aerospace Materials - Aerospace Engineering
Wen Xu Northeastern University China
S. van der Zwaag Novel Aerospace Materials - Aerospace Engineering
Research Group
Novel Aerospace Materials (Aerospace Engineering) (TU Delft)
Copyright: © 2018 H. Farahani, W. Xu, S. van der Zwaag
DOI: https://doi.org/10.1007/s11661-018-4565-8
More Info
expand_more

Published Date

2018

Language

English

Faculty

Aerospace Engineering

Department

Aerospace Structures & Materials

Research Group

Novel Aerospace Materials

Abstract

Formation of the microstructural ferrite/pearlite bands in medium Mn steels is an undesirable phenomenon commonly addressed through fast cooling treatments. In this study, a novel approach using the cyclic partial phase transformation concept is applied successfully to prevent microstructural band formation in a micro-chemically banded Fe-C-Mn-Si steel. The effectiveness of the new approach is assessed using the ASTM E1268-01 standard. The cyclic intercritical treatments lead to formation of isotropic microstructures even for cooling rates far below the critical one determined in conventional continuous cooling. In contrast, isothermal intercritical experiments have no effect on the critical cooling rate to suppress microstructural band formation. The origin of the suppression of band formation either by means of fast cooling or a cyclic partial phase transformation is investigated in detail. Theoretical modeling and microstructural observations confirm that band formation is suppressed only if the intercritical annealing treatment leads to partial reversion of the austenite-ferrite interfaces. The resulting interfacial Mn enrichment is responsible for suppression of the band formation upon final cooling at low cooling rates.