EBSD Study of the Effect of Hot Deformation on Low Carbon Bainitic Structure

Abstract:

The effect of deformation temperature (DT) and thickness reduction on the bainitic structure was investigated under various test conditions by using hot compression on a Gleeble-1500 thermo-mechanical simulation machine, and electron back scattering diffraction (EBSD) technique. In the case of the bainitic structure consisting of granular bainite (GB), lath bainite (LB) and a little ferrite (AF) under the given deformation conditions, DT and thickness reduction have remarkable effect on the transformation kinetics, starting temperature (B) of bainite fast transformation, and the type of bainitic structure. With the decreasing of DT from 810 °C to 730 °C, the starting temperature of transformation B increase from 585 °C to 595 °C. When the thickness reduction was 0 % and 20 %, the microstructure consists of GB, LB and a little AF, whereas as the thickness reduction increase to 40 %, large grain size of LB and GB disappear, and only AF and M/A remained. With the thickness reduction increases from 0 % to 40 %, the effective grain size decreases from 4 μm to 2 μm, and the fraction of HGB increases from 48 % to 57 %.

• Periodical: Materials Science Forum (Volume 993)
• Pages: 513-519
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.993.513
• Online since: May 2020
• Authors: Xin Li Wen*
• Keywords: Bainitic Structure, EBSD, Hot Deformation, Transformation Kinetics, Transformation Starting Temperature

References

[1] Miao C L, Shang C J, Subramanian M. Effect of ausforming and cooling rate on the distribution of high angle boundaries in low carbon bainitic structure. Journal of University of Science and Technology Beijing, 2012, 34(3): 289-297.

[2] Xia D X, Wang X L, Li X C, You Y, Shang C J. The properties and microstructure of third generation X90 pipeline steel. Acta Metallurgica Sinica, 2013,49(3): 271-276.

DOI: 10.3724/sp.j.1037.2012.00480

[3] Chen S K, Li Q Y, Miao Z, Xu F. EBSD and its applications in materials research. Rare Metal Materials and Engineering, 2006, 35(3): 500-504.

[4] Zhang X L, Feng Y R, Zhuang C J, et al. Study on effective particle size of high grade pipeline steels and relationship between CVN. Journal of Materials Engineering, 2008(7): 1-5.

[5] Jiang J X, Tang D, Wu H B, et al. Analysis of propagation behavior of secondary cracks in the E550 offshore platform steel. Journal of Materials Engineering, 2013(6): 35-39.

[6] Diaz-fuentes M, Iza-mendia A, Gutierrez I. Analysis of different acicular ferrite microstructures in low-carbon steels by electron backscattered diffraction. Metallurgical and Materials Transactions A, 2003, 34: 2505-2516.

DOI: 10.1007/s11661-003-0010-7

[7] Zhang X L, Zhuang C J, Ji L K, et al. Effective partical size of high grade pipeline steels. Materials for Mechanical Engineering, 2007, 31(3): 4-8.

[8] Feng R. Metal Physics-The First Volume. Beijing: Science Press, (2000).