Effect of Nb on dynamic strain induced austenite to ferrite transformation
2007; Maney Publishing; Volume: 23; Issue: 4 Linguagem: Inglês
10.1179/174328407x168900
ISSN1743-2847
AutoresPaulo Rangel Rios, Ivaní de Souza Bott, Dagoberto Brandão Santos, Túlio Magno Füzessy de Melo, Jetson Lemos Ferreira,
Tópico(s)Electromagnetic Effects on Materials
ResumoDynamic strain induced transformation (DSIT) is an interesting processing route to obtain ultrafine ferrite grains. In the present work, the effect of Nb on DSIT was investigated. Samples of low C–Mn steels, with and without Nb, were intensively deformed in hot torsion, aiming at the production of ultrafine ferrite grains. After soaking at 1200°C, the samples were cooled to 1100°C, submitted to hot torsion deformation to decrease the grain size and then cooled to 900, 850 or 800°C for further hot torsion deformation. In the steel without Nb, recrystallisation took place before enough deformation could be accumulated to induce ferrite formation, so DSIT would only take place at the lowest temperature investigated, 800°C. In the Nb steel, Nb addition delayed austenite recrystallisation, allowing DSIT ferrite to form at higher temperature than in the steel without Nb, 850°C.
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