Grain Refinement and Deformation Behaviour of Medium Carbon Steel Processed by ECAP

Abstract:

The work presents the results on grains refinement of steel containing 0,45 wt pct carbon resulted from severe plastic deformation (SPD). Different steel structures from prior solutioning and/or thermomechanical treatment were prepared for deformation experimental. A coarse grain ferrite-pearlite structure was achieved applying solutioning. By application of thermomechanical (TM) controlled forging process, performing multistep open die forging, the refined ferrite-pearlite mixture was prepared. Final structure refinement of steel, having different initial structure, was then accomplished applying warm Equal Channel Angular Pressing (ECAP) at 400°C. Employment of this processing route resulted in extensive deformation of ferrite grains and cementite lamellae fragmentation. Applying the highest shear stress (ε_ef - 4) the mixed structure of subgrains and ultrafine grains was present within the ferrite phase. In pearlite grains, modification of cementite lamellae due to shearing, bending, twisting and breaking was found efficient. The coarse cementite lamellae spheroidization was more efficient in prior TM treated steel. The tensile deformation records confirmed strength increase and diversity in strain hardening behaviour.

• Periodical: Key Engineering Materials (Volumes 592-593)
• Pages: 307-312
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.592-593.307
• Online since: November 2013
• Authors: Jozef Zrník, Sergey Dobatkin, Libor Kraus
• Keywords: ECAP, Medium Carbon Steel, Property, Solutioning, SPD, Structure, TM Treatment

References

[1] W. M. Segal, Mater. Sci. Eng. A, 197, 1995, 157.

[2] R. Z. Valiev et al., Mat. Sci. Eng. A, 168, 1993, 141.

[3] S. V. Shin, J. J. Park, Y. S. Park, Mater. Sci. Eng. A, 375, 2002, 178.

[4] K. T. Park, Y. S. Kim, D.H. Shin, Metall. and Materials Trans. A, 32, 2001, 492.

[5] Y. Fukuda et al., Acta Mater. Trans, 50, 2002, 1359.

[6] N. Tsuji et al., Scripta Mater., 47, 2002, 893.

[7] S. M. Sastry, S.V. Dobatkin, V. Sidorova, Russian Metalls, 2, 2004, 139.