Deformation-Induced Austenite-to-Ferrite Massive Transformation in Medium Carbon Steel

• Published in: Metallurgical and materials transactions. A, Physical metallurgy and materials science Physical metallurgy and materials science, 2008-02, Vol.39 (2), p.235-242
• Main Authors: Park, J.K., Kim, K.H., Chung, J.H., Ok, S.Y.
• Format: Article
• Language: English
• Subjects: Alloys; Applied sciences; Carbon steel; Characterization and Evaluation of Materials; Chemistry and Materials Science; Exact sciences and technology; Grain boundaries; Hot rolling; Materials Science; Metallic Materials; Metallurgy; Metals. Metallurgy; Nanotechnology; Structural Materials; Surfaces and Interfaces; Thin Films; Yield stress
• ISSN: 1073-5623; 1543-1940
• DOI: 10.1007/s11661-007-9404-2

Austenite-to-ferrite transformation behavior during hot deformation within the two-phase field was studied in a medium carbon (0.25 wt pct) steel containing 1.1 wt pct Mn-0.25 wt pct Si. Flow softening was observed during hot deformation at temperatures lower than a critical temperature within a two-phase field under the slow strain rate condition. This was because the austenite-to-ferrite transformation during deformation occurred by the deformation-induced massive transformation. The critical temperature was observed to be significantly higher than the T 0 temperature, suggesting that the γ - α equilibrium temperature was largely shifted toward higher temperature during hot deformation. The T 0 shift was believed to be possible because a nonuniform deformation-induced stress can develop between austenite and ferrite phases during hot deformation due to the presence of a significant yield stress difference between two phases.