Phase transformations evaluation on a UNS S31803 duplex stainless steel based on nondestructive testing

Abstract Duplex stainless steel presents special mechanical properties such as, for example, mechanical and corrosion strength, becoming competitive in relation to the other types of stainless steel. One of the great problems of duplex stainless steel microstructural changes study is related to embrittlement above 300 °C, with the precipitation of the α′ phase occurring over the ferritic microstructure. Aiming to characterise embrittlement of duplex stainless steel, hardening kinetics, from 425 to 475 °C, was analysed through the speed of sound, Charpy impact energy, X-ray diffraction, hardness and microscopy parameters. The presence of two hardening stages, detected through the speed of sound, was observed, one being of brittle characteristic and the other ductile. Moreover, the speed of sound showed a direct correlation with the material's hardness. Thus, it is concluded that the speed of sound is a promising nondestructive parameter to follow-up embrittlement in duplex stainless steel.

[1]  M Suresh Kumar,et al.  Failure analysis of a stainless steel pipeline , 2008 .

[2]  J. Pešička,et al.  The structure and low temperature strength of the age hardened Cu-Ni-Sn alloys , 1984 .

[3]  S. Gialanella,et al.  Effect of “475 °C embrittlement” on duplex stainless steels localized corrosion resistance , 2005 .

[4]  A. Badidi Bouda,et al.  Grain size influence on ultrasonic velocities and attenuation , 2003 .

[5]  S. Tavares,et al.  475 °C Embrittlement in a duplex stainless steel UNS S31803 , 2001 .

[6]  R. Simão,et al.  Diagram of phase transformations in the austenite of hardened alloy Fe-28% Mn-8.5% Al-1% C-1.25% Si as a result of aging due to isothermal heating , 2006 .

[7]  Ultrasonic characterization of materials hardness , 2000, Ultrasonics.

[8]  M. D. Mathew,et al.  Low temperature aging embrittlement of CF-8 stainless steel , 1999 .

[9]  J. Kim,et al.  Microstructural change in austenitic Fe-30.0wt%Mn-7.8wt%Al-1.3wt%C initiated by spinodal decomposition and its influence on mechanical properties , 1997 .

[10]  Sandip Bhattacharyya,et al.  Failure analysis of stainless steel tubes in a recuperator due to elevated temperature sulphur corrosion , 2008 .

[11]  G. Goerigk,et al.  Spinodal decomposition of Ni–Nb–Y metallic glasses , 2009 .

[12]  João M.A. Rebello,et al.  Hydrogen damage detection by ultrasonic spectral analysis , 1999 .

[13]  Baldev Raj,et al.  Ultrasonic velocity measurements for estimation of grain size in austenitic stainless steel , 1995 .

[14]  H. Ogi,et al.  Elastic property of aged duplex stainless steel , 2003 .