Print Email Facebook Twitter Effect of the initial microstructure and thermal path on the final microstructure and bendability of a high strength ferrite-martensite dual phase steel Title Effect of the initial microstructure and thermal path on the final microstructure and bendability of a high strength ferrite-martensite dual phase steel Author Lan, H. (TU Delft Novel Aerospace Materials; Northeastern University) Tang, S. (TU Delft Novel Aerospace Materials; Northeastern University) DU, Linxiu (Northeastern University) LI, Jianping (Northeastern University) van der Zwaag, S. (TU Delft Novel Aerospace Materials) Date 2021 Abstract The combined effects of the initial microstructure and heating rate on ferrite recrystallization, austenite formation and transformation kinetics of a regular ferrite-martensite dual phase steel are investigated. Special attention is given to the effect of the martensite distribution on mechanical properties, particularly the bendability. Ferrite recrystallization in the cold rolled bainitic grade proceeds faster than in the ferrite-pearlite grade. The reason for this is the higher defect density leading to a lower activation energy. The junctions between the cementite and the ferrite grain boundaries are the preferred austenite nucleation sites. Those ferrite boundaries far away from the cementite can only be invaded by austenite through carbon supplied by cementite dissolution and carbon segregation. When using a high heating rate, nucleation of austenite can occur in a massive-like manner, and the austenite transformation kinetics is remarkably accelerated. The bendability of DP steel is determined by a combination of structural parameters, such as grain size, volume fraction as well as spatial distribution of martensite. A short in-line holding-step during heating can alleviate the banding severity and improve the bendability of this ferrite-martensite DP steel. Subject Austenite transformation kineticsBendabilityDual phase steelFerrite recrystallizationMartensite distribution To reference this document use: http://resolver.tudelft.nl/uuid:0eb2810f-8208-47c3-b4d0-a42dd9a50e47 DOI https://doi.org/10.2355/ISIJINTERNATIONAL.ISIJINT-2020-613 ISSN 0915-1559 Source ISIJ International, 61 (5), 1650-1659 Part of collection Institutional Repository Document type journal article Rights © 2021 H. Lan, S. Tang, Linxiu DU, Jianping LI, S. van der Zwaag Files PDF en.pdf 1.99 MB Close viewer /islandora/object/uuid:0eb2810f-8208-47c3-b4d0-a42dd9a50e47/datastream/OBJ/view