Influence of Rolling Temperature and Cooling Rate on Microstructure and Properties of Pipeline Steel Grades

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Abstract:

Thermo-mechanical control processing (TMCP) is a powerful tool for development of high strength low alloy (HSLA) steels. The understanding of the effect of process parameters on the microstructure of these steels is a key aspect for the optimization of their mechanical properties. The influence of the rolling temperatures and the cooling conditions on the texture, strength and toughness of HSLA steel was investigated. Two stage controlled rolling (roughing and finishing) was carried out on a laboratory rolling mill. Four different compositions were rolled by maintaining same roughing conditions but varying the process parameters of the finish rolling, namely, start finish rolling temperature (SFRT), finish rolling and cooling temperatures. Subsequent to rolling, two different cooling routes were used, namely, air-cooling (AC) and accelerated water cooling (ACC). For the ACC route, the plates were subsequently heat treated to simulate coiling. The microstructure and texture obtained before and after each TMCP schedule were characterized quantifying the phases, grain size and texture by means of EBSD and XRD and associated with the mechanical properties. It was found that SFRT has a strong impact on both strength and toughness if the material was air-cooled. Plates rolled at lower temperature showed better strength and toughness than ones rolled at high temperature in both air-cooling and ACC due to grain refinement. However, for the material that was processed through ACC and coiling simulation, the strength increased without any substantial effect on the toughness. These results provide an interesting insight on the industrial processing of HSLA steels.

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Periodical:

Materials Science Forum (Volumes 706-709)

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2710-2715

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Online since:

January 2012

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[1] H. Vergote, Current status of TMP in Hot Strip Mill. TMP 2004 Liege pp.9-18.

Google Scholar

[2] J.D. Jones, A.B. Rothwell; Deformation under hot working conditions, pp.72-82; (1968).

Google Scholar

[3] A. Arrowsmith: J. Iron Steel Inst. 1924, 110, 317-319.

Google Scholar

[4] I. Tamura et al. The thermo-mechanical processing of high-strength low allow steels. (1988).

Google Scholar

[5] T. Tanaka International metals Reviews, vol 26, (1981), pp.185-212.

Google Scholar

[6] M. -C. Zhao et al. Materials Science and Engineering A335 (2002) p.14–20.

Google Scholar

[7] R. Phillips, J.A. Chapman; J. Iron Steel Int., (1966).

Google Scholar

[8] Buehler SUM-METTM. The science behind material preparation p.75.

Google Scholar

[9] P. Van Houtte: The MTM-FHM software system version 2. K. U. Leuven, Belgium.

Google Scholar

[10] G. Krauss, S.W. Thomson ISIJ Int (1995) pp.937-945.

Google Scholar

[11] M. -C Zhao et al. Materials Letters 57 (2003) 1496-1500.

Google Scholar

[12] M. Liebeherr, Microstructure-Property Relationship in 22mm Thick X80 Coil Skelp. IPC 2010 -31250 Canada.

DOI: 10.1115/ipc2010-31250

Google Scholar

[13] M. Diaz-Fuentes, A. Iza-Mendia, I. Gutierrez, Analysis of different acicular ferrite microstructures in low-carbon steels by electron backscattered diffraction. Study of their toughness behavior, Metall. Mater. Trans., Vol 34A, 2003, pp.2505-2516.

DOI: 10.1007/s11661-003-0010-7

Google Scholar

[14] B. Hwang, et al. Effective grain size and Charpy impact properties of high-toughness X70 pipeline steels, Metall. Mater. Trans., Vol 36A, (2005).

DOI: 10.1007/s11661-005-0331-9

Google Scholar

[15] R. K. Ray, J. J. Jonas, M.P. Butron-Guillen and J. Savoie Transformation Textures in Steels ISIJ International. Vol. 34 (1994), No. 12.

DOI: 10.2355/isijinternational.34.927

Google Scholar

[16] W. Oldfield, ASTM Standardizations News, (1975) pp.24-29.

Google Scholar

[17] Wan, Q, -m, et al., Analysis method of Charpy V-notch impact data before and after electron beam welding reconstruction. Nucl. Eng. Des. (2011).

Google Scholar

[18] L.I. Zhuang Controlled rolling and cooling process for low carbon Cold forming steel, Wuhan University (2010).

Google Scholar