Optimization of Nb HSLA Microstructure Using Advanced Thermomechanical Processing in a CSP Plant

Abstract:

Article Preview

There are two obstacles to be overcome in the CSP production of HSLA heavy gauge strip and skelp, especially for API Pipe applications. First, the microalloying should be conserved by eliminating the high temperature precipitation of complex particles. Second, the heterogeneous microstructure that normally results from the 800 micron initial austenite in the 50mm slab as it is rolled to 12.5mm skelp must be eliminated to optimize the final microstructure and improve the final mechanical properties. Alteration in the hot rolling sequence can strongly homogenize the final austenite and resulting final ferritic microstructure. When coupled with a low coiling temperature near 550°C, the new rolling practice can result in Nb HSLA steels that can easily meet requirements for strength, toughness and ultrasonic testing in 12.5mm skelp gauges for X70 API pipe applications. The underlying physical metallurgy of these two breakthroughs will be presented and discussed in detail.

Info:

Periodical:

Materials Science Forum (Volumes 539-543)

Main Theme:

Edited by:

T. Chandra, K. Tsuzaki, M. Militzer , C. Ravindran

Pages:

28-35

Citation:

A. J. DeArdo et al., "Optimization of Nb HSLA Microstructure Using Advanced Thermomechanical Processing in a CSP Plant", Materials Science Forum, Vols. 539-543, pp. 28-35, 2007

Online since:

March 2007

Export:

Price:

$38.00

[1] International Symposium on Thin Slab Casting and Rolling (TSCR' 2002), Guangzhou, China, December 3-5, 2002, Chinese Society for Metals.

[2] Continuous Caster Roundup-2001, Iron & Steelmaker, ISS, Warrendale, PA, Vol. 28, No. 11, (2001), 36.

[3] G. Flemming et al., Metall. Plant and Tech., Vol. 11, 1988, pp.16-35.

[4] Y. Li, et al., Proc. Materials Solutions Conference 2002, Columbus, OH, ASM International, (2002), 5.

[5] A. J. DeArdo, Nb in Modern Steels, International Materials Reviews, Vol. 48, No. 6, (2003), 371.

[6] A.J. DeArdo, et al, in ref.

[1] 194.

[7] C. I. Garcia, et al., in ref.

[1] 386.

[8] Y. Li, et al., in ref.

[1] 218.

[9] A. Ruiz-Aparicio, MS Thesis, University of Pittsburgh, (2004).

[10] H. Hu, Recovery and Recrystallization of Metals, Interscience, NY, 1963, 311.

[11] A.J. DeArdo, Microalloying '95, ISS-AIME, Warrendale, PA, 1995, 15.

[12] I. Kozasu et al., Microalloying'75, Union Carbide Corporation, New York, NY, 1977, 120. 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% 0. 050 0. 075 0. 100 0. 125 0. 150 0. 175 0. 200 0. 225 0. 250 0. 275 0. 300 0. 325 0. 350 0. 375 Thickness (in) Cumulative % 50 ksi 60 ksi 70 ksi 80 ksi.

Fetching data from Crossref.
This may take some time to load.