Determination of the Critical Strains for the Initiation of Dynamic Transformation and Dynamic Recrystallization in Four Steels of Increasing Carbon Contents. Issue 5 (5th December 2012)

• Record Type: Journal Article
• Authors: Ghosh, Chiradeep; Basabe, Vladimir V.; Jonas, John J.
• Is Part Of: Steel research international. Volume 84:Issue 5(2013:May)
• Page Start: 490
• Page End: 494
• Publication Date: 2012-12-05
• Subjects: dynamic transformation -- dynamic recrystallization -- strain rate -- torsion testing -- work hardening; Steel -- Periodicals; Steel -- Metallurgy -- Periodicals; 669.142
• DOI: 10.1002/srin.201200188
• Languages: English
• ISSNs: 1611-3683

Abstract

Abstract: Hot torsion tests are carried on three plain carbon steels and a Nb microalloyed steel of increasing C concentrations. The tests are performed at strain rates up to 4 s −1 and over the temperature range 743–917°C. The onsets of dynamic transformation (DT) and dynamic recrystallization (DRX) are detected using the double‐differentiation method. Both mechanisms are initiated under all testing conditions but one. The critical strain for DT increases with temperature while the reverse dependency is exhibited by the critical strain for DRX. Abstract : The formation of ferrite during rolling at temperatures above the Ae3 is a controversial topic. Here it is shown that strong evidence for the occurrence of this transformation can be obtained directly from the flow curve of the deformation using the double‐differentiation method. The critical strain for dynamic transformation is shown to be distinctly less than that for dynamic recrystallization.