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Effects of Annealing Conditions on Recrystallization, Texture, and Average Normal Anisotropy Coefficient of a Niobium‐Stabilized Ferritic Stainless Steel
Author(s) -
Rodrigues Daniella Gomes,
Alcântara Cláudio Moreira,
Santos Dagoberto Brandão,
Oliveira Tarcísio Reis,
Gonzalez Berenice Mendonça
Publication year - 2017
Publication title -
steel research international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.603
H-Index - 49
eISSN - 1869-344X
pISSN - 1611-3683
DOI - 10.1002/srin.201700214
Subject(s) - recrystallization (geology) , materials science , annealing (glass) , metallurgy , nucleation , grain size , microstructure , niobium , electron backscatter diffraction , dynamic recrystallization , composite material , hot working , thermodynamics , paleontology , physics , biology
The present study investigates the influence of the heating rate on annealing, microstructure, recrystallization, texture, and the average normal anisotropy coefficient, r ¯value, of a niobium‐stabilized ferritic stainless steel (i.e., an ASTM 430‐type steel). Experiments with 0.10 and 41.5 °C s −1 heating rates are performed after 85% cold rolling. The sample's characterization is performed by optical microscopy, transmission electron microscopy, electron backscatter diffraction, and hardness tests. The tensile tests are performed to determine ther ¯value and the Δ r value . The results show that the extent of recrystallization and the average grain size decreases significantly when the heating rate is raised. This increased heating rate causes a weakening of γ ‐fiber and of the{ 334 } 〈 483 〉and{ 554 } 〈 225 〉components, and leads to an even more randomized recrystallization texture. Ther ¯value after having achieved full recrystallization is improved when the heating rate is reduced. Ther ¯ = 1.99 is obtained for γ / θ = 5.11 with a lower heating rate. These observed differences in recrystallization, grain size, and recrystallization texture are mainly related to the nucleation rate during annealing. The high intensity of the γ ‐fiber is attributed to the number advantage of γ ‐fiber grains after full recrystallization.