Isothermal Austenite–Ferrite Phase Transformations and Microstructural Evolution during Annealing in Super Duplex Stainless Steels

Metals

Andrea Gruttadauria¹  Carlo Mapelli¹  Silvia Barella¹  Davide Mombelli¹  Andrea Francesco Ciuffini¹  Cosmo Di Cecca¹ 

[1] Department of Mechanical Engineering, Politecnico di Milano, via La Masa 34, 20156 Milano, Italy;

关键词: duplex stainless steel;    isothermal austenite–ferrite transformation;    multicomponent diffusion;    local equilibrium;    additivity rule;   

DOI  :  10.3390/met7090368

来源: DOAJ

【 摘 要 】

Super Duplex Stainless Steels (SDSSs) are composed of α-ferrite and γ-austenite grains, the simultaneous presence of which forms an optimal microstructure to achieve the best combination of mechanical and corrosion resistance properties. Moreover, international quality standards are strict about the phase fraction ratio. The purpose of this work is the achievement of a better description of the phase ratio evolution taking place during annealing at 1080 °C in the super duplex stainless steels F53–S32750 and F55–S32760. The experimental results show a damped sinusoidal trend in the α/γ phase ratio evolution with the increase of the soaking time of thermal treatment. This can be described by coupling both the competitive coarsening growth regime and the concept of the local equilibrium phase transformations, pointing out a good correspondence with the experimental data. Further, recrystallization phenomena also play a major role. Finally, the additivity character of the observed processes has been proven.

【 授权许可】

Unknown