Microstructure and corrosion resistance of Z3CN20.09M stainless steels after different thermo-mechanical processing

• Published in: Journal of nuclear materials Vol. 577; p. 154300
• Main Authors: Chen, Xufeng, Tian, Donghua, Ling, Ligong, Liu, Tingguang, Wang, Hui, Chen, Yinqiang, Lu, Yonghao
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.04.2023
• Subjects: Corrosion resistance; Duplex stainless steel; Low-∑ CSL boundary; Microstructure; Thermo-mechanical processing; Corrosion resistance; Duplex stainless steel; Thermo-mechanical processing; Microstructure; Low-∑ CSL boundary
• ISSN: 0022-3115; 1873-4820
• DOI: 10.1016/j.jnucmat.2023.154300

Thermo-mechanical process was used to control the microstructure of a nuclear grade cast duplex stainless steel Z3CN20.09M. It is revealed that heat treatment alone cannot change the casting microstructure of coarse columnar grains. After a low-strain deformation (7% tension) and annealing at 1180 °C, a high fraction of low-∑ CSL boundaries, about 76%, were formed due to the strain induced boundary migration. After higher deformation (>10%) and annealing, recrystallization microstructure with fine equiaxed grains could be formed. The electrochemical tests in lithium borate aqueous solution showed that a high fraction of low-∑ CSL boundaries and fine grains after the thermo-mechanical processing improved the corrosion resistance of the Z3CN20.09M.