Investigations into the Transformation of Sigma Phase in Shot-peened Duplex Stainless Steel at Elevated Temperatures by Rietveld Method

Author:  F. Qiang, J. Chuanhai, H. Pan
Source:  Conf Proc 2014: ICSP-12 Goslar, Germany (pgs.494-498)
Doc ID:  2014126
Year of Publication:  2014
Abstract:  
Phase transformation and growth of sigma phase in shot-peened duplex stainless steel (DSS) S32205 was measured by X-ray diffraction during 64-min isothermal heat treatment at temperature between 600°C and 700°C. Quantitative analysis of phase in duplex stainless steel S32205 at elevated temperature was obtained by Rietveld method. Shot peening can facilitate the formation of sigma phase in tnear surface layers at elevated temperature, which is due to domain sizes refined. The content of sigma phase is most at layer depth of 10 μm rather than in surface layer at temperature of 700 °C and mechanism of formation was discussed. Sigma phase is known to adversely affect mechanical properties and corrosion resistance of DSS alloy. Therefore, it is important to assess phase composition and performance in shot-peened DSS subsurface layer at elevated temperatures.