Eutectoid Decomposition of δ-Ferrite in Ferritic-Austenitic Duplex Cast Steel - Structural and Morphological Study

Abstract:

The influence of time and temperature of ageing on the σ-phase morphology in ferritic-austenitic cast steel have been investigated in this study. The morphology and quantity of the σ-phase were analyzed by using optical microscope, X-ray diffractometry, scanning electron microscope and image analysis, respectively. The annealing temperature has a significant influence on the morphology, volume fraction and the dynamics of σ-phase precipitation. Surface development of the σ-phase decreases from R=4.3, for the cast steel annealed at 700°C to R=2.4 for the cast steel annealed at 900°C, and the volume fraction Vv_σ from 50.8% to 26.5%, respectively. The most rapid progress of δ → σ + γ’ transformation was observed at 800°C.

• Periodical: Materials Science Forum (Volumes 706-709)
• Pages: 2314-2319
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.706-709.2314
• Online since: January 2012
• Authors: D. Dyja, Z. Stradomski, Cezary Kolan, Grzegorz Stradomski
• Keywords: Aging, Duplex Cast Steel, Microstructure, Precipitation, Sigma Phase

References

[1] R. Badji, M. Bouabdallah, B. Bacroix, C. Kahloun, B. Belkessa, H. Maza, Phase transformation and mechanical behaviour in annealed 2205 duplex stainless steel welds, Materials Characterization 59, (2008), 447-453.

DOI: 10.1016/j.matchar.2007.03.004

[2] K. A. Bakken, Cost effective materials selections – what is true?, Stainless Steel World Conference & Expo, Maastricht Netherlands, (2005), pp.18-23.

[3] S.K. Ghosh, S. Mondal, High temperature ageing behaviour of a duplex stainless steel, Materials Characterization 59, (2008), 1176-1783.

DOI: 10.1016/j.matchar.2008.04.008

[4] Y-J. Kim, O. Ugurlu, C. Jinag, B. Gleeson, Microstructural evolution of secondary phases in the cast duplex stainless steel CD3MN and CD3MWCuN, Metallurgical and Materials Transactions A, Vol. 38A, (2007), 203-211.

DOI: 10.1007/s11661-006-9049-6

[5] H. Sieurin, R. Sandstrom, Sigma phase precipitation in duplex stainless steel 2205, Materials Science and Engineering A 444, (2007), 271-276.

DOI: 10.1016/j.msea.2006.08.107

[6] K.W. Wong, C.H. Shek, W. Zhang, J.K.L. Lai, Sigma phase dissolution in duplex stainless steel at elevated temperature studied by thermal analysis, Material Letters, (2008), 3991-3994.

DOI: 10.1016/j.matlet.2008.05.040

[7] P. Kangas, J.O. Nilsson, Influence of phase transformations on mechanical properties and corrosion properties in duplex stainless steels, Stainless Steel World Conference & Expo, Maastricht Netherlands, (2005), pp.278-283.

[8] C.J. Park, R.V. Shankar, H.S. Kwon, Effect of sigma phase on the initiation and propagation of pitting corrosion of duplex stainless steel, Corrosion Vol. 61, No. 1 (2005) 76-83.

DOI: 10.5006/1.3278163

[9] D. Dyja, Z. Stradomski, A. Pirek, Microstructural and fracture analysis of aged cast duplex steel, Strength of Materials, Vol. 40, No. 1, (2008), pp.122-125.

DOI: 10.1007/s11223-008-0032-x

[10] T.H. Chen, K.L. Weng, J.R. Yang, The effect of high-temperature exposure on the microstructual stability and thougness property in a 2205 duplex stainless steels, Materials Science and Engineering A338, (2002), 259-270.

DOI: 10.1016/s0921-5093(02)00093-x

[11] D. Dyja, Z. Stradomski, S. Stachura, Optimisation of structure and operational properties of a duplex cast steel, Duplex 2007 International Conference & Expo, Grado Italy, (2008).

[12] L. Duprez, B.D. Cooman, N. Akdut, Redistribution of the substitutional elements during a and c phase formation in a duplex stainless steel, Steel Research 72, No. 8, (2001), 311-316.

DOI: 10.1002/srin.200100123

[13] Z. Stradomski, D. Dyja, Characterization of solidification and solid state transformation in duplex cast steel: Thermo-Calc investigation, Archives of Foundry Engineering Vol. 7, Issue 3, (2007), 269-272.

[14] Z. Stradomski, D. Dyja, A.M. Galkin, Role of carbon in the crystallization of duplex steels and the solidification of their ingots, Steel in Translation, Vol. 37 No 3, (2007), 234-237.

DOI: 10.3103/s096709120703014x

[15] Stradomski Z., Soiński M.S., Stradomski G.: The assessment of hot cracking susceptibility of ferritic-austenitic cast iron. Archives of Foundry Engineering (2010), Vol. 9, Issue 3, 21-24.

DOI: 10.1515/afe-2016-0101