Microstructural Evolution and Mechanical Properties of Low C-Mn Steels Subjected to Accelerated Cooling

Abstract:

Microstructure consisting of ferrite and bainite in low C-Mn steels with different manganese contents (0.75-1.49 mass %) can be formed by accelerated cooling. Microstructure observation reveals that the transformation products of 0.75%Mn and 1.06%Mn steel mainly consist of equiaxed ferrite and pearlite when hot finish deformation was processed at the temperature of 800°C, while the transformed products mainly contained irregular ferrite and upper bainite when finish rolling temperature (FRT) increases to 850°C or 900°C. However, a large amount bainite can also be attained in 1.49%Mn steel when FRT decreased to 800°C. The strength increases by about 100MPa with the increase of manganese content from 0.75% to 1.49%. The 1.06%Mn steel exhibits a superior strength-elongation combination by deforming at FRT of 850°C and then accelerated cooling at the cooling rate of about 40°C/s to coiling temperature in the range of 490~510°C.

• Periodical: Materials Science Forum (Volume 893)
• Pages: 245-251
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.893.245
• Online since: March 2017
• Authors: Long Li*, Guang Su, Xiao Bin Li
• Keywords: Rolling , Accelerated Cooling, Bainite, Low C-Mn Steel, Mechanical Properties

References

[1] M. Jahazi, B. Egbali, The influence of hot rolling parameters on the microstructure and mechanical properties of an ultra-high strength steel, Journal of Materials Processing Technology 103 (2000) 276-279.

DOI: 10.1016/s0924-0136(00)00474-x

[2] M.C. Zhao, K. Yang, Y.Y. Shan, Comparison on strength and toughness behaviors of microalloyed pipeline steels with acicular ferrite and ultrafine ferrite, Materials Letters 57 (2003) 1496-1500.

DOI: 10.1016/s0167-577x(02)01013-3

[3] P.D. Hodgson, M.R. Hickson, R.K. Gibbs, Ultrafine ferrite in low carbon steel, Scripta Materialia 40 (1999) 1179-1184.

DOI: 10.1016/s1359-6462(98)00411-4

[4] M.R. Hickson, R.K. Gibbs, P.D. Hodgson, The Effect of Chemistry on the Formation of Ultrafine Ferrite in Steel, ISIJ International 39 (1999) 1176-1180.

DOI: 10.2355/isijinternational.39.1176

[5] B. Q, Han, S. Yue, Processing of ultrafine ferrite steels, Journal of Materials Processing Technology 136 (2003) 100-104.

DOI: 10.1016/s0924-0136(02)01014-2

[6] L. Li, C.Z. Yang, H. Ding, Study on microstructures and mechanical properties of B510L steel by TMCP, Materials Science Forum 475-479 (2005) 77-80.

DOI: 10.4028/www.scientific.net/msf.475-479.77

[7] P.G. Xu, H.S. Fang, B.Z. Bai, Z.J. Wang, Z.G. Yang, J.F. Huang, New Duplex Microstructure of Grain Boundary Allotriomorphic Ferrite/Granular Bainite. J. Iron & Steel Res., Int. 9 (2002) 33-38.

DOI: 10.1016/j.msea.2004.04.073

[8] J.R. Bradley, H.I. Aaronson, Growth kinetics of grain boundary ferrite allotriomorphs in Fe-C-X Alloys, Metallurgical transactions A 12 (1981) 1729-1741.

DOI: 10.1007/bf02643755

[9] S.K. Liu, J. Zhang, The influence of the Si and Mn concentration on the kinetics of the bainite transformation in Fe-C-Si-Mn alloys, Metallurgical Transaction A 21 (1990) 1517-1525.

DOI: 10.1007/bf02672566

[10] M.C. Zhao, K. Yang, F.R. Xiao, Y.Y. Shan, Continuous cooling transformation of undeformed and deformed low carbon pipeline steels, Materials Science and Engineering A 355 (2003) 126-136.

DOI: 10.1016/s0921-5093(03)00074-1

[11] J.S. Byun, J. H Shim, Y.W. Cho, Influence of Mn on microstructural evolution in Ti-killed C-Mn steel, Scripta Materialia 48 (2003) 449-454.

DOI: 10.1016/s1359-6462(02)00437-2

[12] P.C.M. Rodrigues, E.V. Pereloma, D.B. Santos, Mechanical properities of an HSLA bainitic steel subjected to controlled rolling with accelerated cooling, Materials Science and Engineering A 283 (2000) 136-143.

DOI: 10.1016/s0921-5093(99)00795-9

[13] M. Thompson, M. Ferry, P.A. Manohar, Simulation of Hot-band Microstructure of C-Mn Steels during high Speed Cooling, ISIJ Int. 41(2001) 891-899.

DOI: 10.2355/isijinternational.41.891

[14] Y.D. Huang, W.Y. Yang, Z.Q. Sun, Formation of ulrafine grained ferrite in low carbon steel by heavy deformation in ferrite or dual phase region, Journal of Materials Processing Technology 134 (2003) 19-25.

DOI: 10.1016/s0924-0136(02)00272-8

[15] L.X. Du, C.B. Zhang, H. Ding, X.H. Liu, G.D. Wang, Determination of upper limit temperature of strain-induced transformation of low carbon steels, ISIJ Int. 42(2001) 1119-1124.

DOI: 10.2355/isijinternational.42.1119

[16] H. Ding, L. Li, C.Z. Yang, X.H. Liu, Microstructures of an Ultrafine Grained SS400 Steel in an Industrial Scale, J. Mater. Sci. Technol. 22(2006) 145-148.