Influence of Solution Treatment Duration on Microstructural Features of an Industrial Forged UNS S32750/1.4410/F53 Super Duplex Stainless Steel (SDSS) Alloy

The microstructural changes induced by solution treatment of an industrial forged F53 Super Duplex Stainless Steel alloy were studied, in order to emphasize how component phases are influenced by heat treatment temperature and duration. The solution treatment was done at a temperature of 1100°C, with variable holding times: 0.6 ks (10 min), 3.6 ks (60 min) and 10.8 ks (180 min). Scanning electron microscopy–electron backscattered diffraction was used as main characterization technique, to obtain and analyse data referring to microstructural features, such as: nature and morphology of constituent phases, average grain-size and grain misorientation. It was shown that in all studied cases the microstructure consisted of a mixture of about 45% δ-Fe (ferrite) and 55% γ-Fe (austenite). Besides δ-Fe and γ-Fe phases, other phases were also identified, such as τ-phase (chromium-iron carbide), σ-phase (chromium-iron) and δ-(Cr–Fe) (ferrite).