Thermodynamic Analysis of the Effect of Compositional Inhomogeneity on Phase Transformations in a 13Cr6Ni2Mo Supermartensitic Stainless Steel

Abstract:

Supermartensitic stainless steels possess an excellent combination of strength, toughness and corrosion resistance and have attracted an increased industrial attention especially from the offshore oil and gas industry, where those materials are already successfully in use. It is well known that the mechanical properties of this type of steels are strongly dependent on the fraction of retained austenite, which is controlled by heat treatment. Because the products manufactured out of these steels are in large sections, temperature gradients and corresponding compositional inhomogeneities are inevitable. Also during heat treatment partitioning of elements between the phases will give local concentrations far removed from the bulk levels. In the present work a 13Cr6Ni2Mo supermartensitic stainless steel is thermodynamically analyzed using the Thermo-Calc^® software package where the influence of compositional variations on phase transformations is investigated, in particular the effect of changes in the Ae₃-temperature is discussed.

• Periodical: Solid State Phenomena (Volumes 172-174)
• Pages: 899-904
• DOI: https://doi.org/10.4028/www.scientific.net/SSP.172-174.899
• Online since: June 2011
• Authors: Andrea Bojack, Lie Zhao, Jilt Sietsma
• Keywords: Retained Austenite, Supermartensitic Stainless Steel, Thermodynamic Calculation

References

[1] D. Carrouge, H.K.D.H. Bhadeshia, P. Woollin: Science and Technology of Welding and Joining 2004, Vol. 9, No. 5, pp.377-389.

DOI: 10.1179/136217104225021823

[2] D. Carrouge, H.K.D.H. Bhadeshia, P. Woollin: Microstructural Change in High Temperature Heat-Affected Zone of Low Carbon Weldable 13 %Cr, Martensitic Stainless Steel, in Stainless Steel World, October 2002, pp.16-23.

[3] P.D. Bilmes, M. Solari, C.L. Llorente: Materials Characterization 46 (2001), pp.285-296.

[4] Y. Wei: Microstructural Characterization and Mechanical Properties of Super 13% Cr Steel, PhD-thesis, The University of Sheffield, (2005).

[5] H. van der Winden, P. Toussaint, L. Coudreuse: Past, present and future of weldable supermartensitic alloys in: Proc. Supermartensitic Stainless Steels 2002, KCI Publishing BV, 2002, Brussels, pp.9-13.

[6] K. Kondo et al.: Alloy Design of Super 13Cr Martensitic Stainless Steel: Proc. Supermartensitic Stainless Steels 1999, KCI Publishing BV, 1999, Brussels, pp.11-18.

[7] R.W.K. Honeycombe, H.K.D.H. Bhadeshia: Steels: Microstructure and Properties, 2nd edition, Edward Arnold, London, (1995).

[8] G. Rožnovská et al.: The Effect of Heat Treatment on Microstructure and Properties of a 13Cr6Ni2. 5Mo Supermartensitic Steel, Sborník vědeckých Vysoké školy báňské – TU Ostrava, číslo 1, rok 2005, ročník XLVIII, řada hutnická článek č. 1241, pp.225-231.

[9] W. Xu et al.: Modelling Chi-Phase Precipitation in High Molybdenum Stainless Steel, Advanced Materials Research Vols. 15-17 (2007), pp.531-536.

DOI: 10.4028/www.scientific.net/amr.15-17.531

[10] A.F. Padilha, P.R. Rios: ISIJ International, Vol. 42 (2002), No. 4, pp.325-337.

[11] Information on http: /www. corusgroup. com/file_source/StaticFiles/Business%20Units/Engineering%20steels/ SF1325. PDF.