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Rapid annealing of severely deformed low carbon steel in subcritical temperature range

Ghiabakloo, H ; Sharif University of Technology

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  1. Type of Document: Article
  2. DOI: 10.1007/s12540-017-6753-2
  3. Abstract:
  4. A low-carbon steel sheet containing 0.05 C, 0.203 Mn, and 0.0229 Si (all in wt%) was rapidly annealed in a temperature range of 300 °C to 600 °C after severe plastic deformation by using constrained groove pressing (CGP) technique. Microstructure evolution was investigated by scanning electron and optical microscopes. Mechanical properties were evaluated by hardness measurements and shear punch test. The results showed a thermal stability up to 400 °C where recrystallization did not occur in the specimens even after 7200 s. This thermal stability is in agreement with previously reported results of conventional annealing of the same steel after CGP. However, annealing at 500 °C and 600 °C led to recrystallization which started after holding times of 600 s and 20 s, respectively. Longer holding times resulted to grain growth and deterioration of strength and hardness, but the final strength and hardness were still higher than those of conventionally annealed specimens. The reason has been attributed to no abnormal grain growth in the present study, in contrast to that occurs after conventional annealing of CGPed low carbon steel. The kinetics of recrystallization at 600 °C was studied using the celebrated Johnson-Mehl-Avrami-Kolmogorov (JMAK) model; the results showed a bi-linear JMAK plot indicating two different stages of recrystallization rate before and after 70% recrystallization. © 2017, The Korean Institute of Metals and Materials and Springer Science+Business Media B.V
  5. Keywords:
  6. Hardness test ; Metals ; Microstructure ; Rapid annealing ; Severe plastic deformation
  7. Source: Metals and Materials International ; Volume 23, Issue 5 , 2017 , Pages 984-993 ; 15989623 (ISSN)
  8. URL: https://link.springer.com/article/10.1007/s12540-017-6753-2