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Determination of residual stress and critical rolling temperatures in a microalloyed steel with low carbon and niobium contents
Author(s) -
Gómez Manuel,
Hernanz Oscar,
Medina Sebastián F.,
Tarín Pascual
Publication year - 2002
Publication title -
steel research
Language(s) - English
Resource type - Journals
eISSN - 1869-344X
pISSN - 0177-4832
DOI - 10.1002/srin.200200013
Subject(s) - microalloyed steel , niobium , materials science , metallurgy , residual stress , flow stress , strain rate , microstructure , austenite
Using torsion tests, residual stress (Δσ) and critical rolling temperatures ( T nr , A r3 , A r1 ) have been determined for a low Nb content microalloyed steel by means of simulation of rolling cycles and subsequent representation of mean flow stress versus the inverse of the temperature. The above magnitudes were determined as a function of interpass time for two strains applied in each pass (0.20, 0.35), respectively. Among the results found, it is notable that Δσ decreases with longer interpass times until it reaches zero, and is greater the smaller the strain applied. With regard to the cooling transformation temperatures A r3 and A r1 , these were found to be practically independent of the interpass time and were higher for smaller applied strains. Temperatures A r3 and A r1 were also determined by dilatometry, and comparison of these values showed that both methods yield similar results, except in the value of A r1 .