Abstract
The effects of thermal aging time at 400 °C on the microstructure and mechanical and corrosion behaviors of Z3CN20.09M cast stainless steel were investigated; and the corresponding thermal aging mechanism was studied. It was revealed that the changes in mechanical properties after thermal aging were mainly caused by the iron-rich phase (α) and the chromium-rich phase (α’) produced by the amplitude-modulation decomposition of ferrite. A similar trend of thermoelectric potential during thermal aging was determined in relation to the Charpy impact energy. However, the corrosion resistance of Z3CN20.09M cast stainless steel deteriorates as thermal aging time increases. When the thermal aging is longer than 3000 h, the precipitation of G phase has a great influence on the corrosion resistance. The interfacial matching relationship between G phase and the surrounding ferrite was established by selected area electron diffraction of HRTEM. The relationship is of cube-on-cube phase boundary type. The impact fracture mechanisms in relation to thermal aging time were also studied and compared.
Highlights
In the past few decades, nuclear power, well known as the clean energy technology, has played an important role in industrial applications because of its low-carbon, highefficiency nature [1,2,3]
Due to the deficiency of Cr in G phases and concentration of Cr in matrix, severer corrosion occurred after more thermal aging
During the 400 ◦C thermal aging treatment of Z3CN20-09M cast stainless steel, the morphology and content of ferrite and austenite do not change significantly. This proves that the changes in mechanical and corrosion properties after thermal aging are independent of the morphology of ferrite in steel
Summary
In the past few decades, nuclear power, well known as the clean energy technology, has played an important role in industrial applications because of its low-carbon, highefficiency nature [1,2,3]. Z3CN20.09M cast austenitic stainless steel (containing 12%–18% ferrite) has been widely used in the primary coolant pipes of in-service pressurized water reactors [12]. This kind of stainless steel undergoes thermal aging embrittlement during long-term service in reactors (~288–327 ◦C, ~16 MPa), resulting in deficient impact toughness and poor corrosion resistance [13,14,15]. The present work is dedicated to investigating the microstructural, mechanical and corrosion properties of Z3CN20.09M cast austenitic stainless steel over a far longer thermal aging time range (0–15,000 h, 400 ◦C). We tried to enhance the reliability of a non-destructive method for testing the thermoelectric potential of cast austenitic stainless steel
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
