Effect of cerium additive on low temperature impact properties of S32750 super duplex stainless steel

doi:10.13251/j.issn.0254-6051.2021.11.007

Abstract

Abstract: The differences of impact absorption energy and energy composition between the two super duplex stainless steels with different Ce additives in the range of 20 ℃ to -100 ℃ was analyzed by means of Charpy impact test and oscilloscope shock method. Effects of Ce additive on modification of inclusion and impact fracture behavior of the steel were studied by means of Aspex automatic scanning electron microscope, SEM and EDS. The results show that the low temperature impact fracture resistance of the high Ce tested steel is obviously better than that of the low Ce tested steel, and the ductile-brittle transition temperature of the former is 16 ℃ lower than that of the latter. The addition of cerium increases the impact absorbed energy at －80 ℃ by 45 J, which is mainly due to the increase of crack growth energy W_P (76%). The results of impact fracture morphology observation and inclusion analysis show that the impact fracture of low Ce tested steel at －80 ℃ shows complete cleavage fracture. Compared with the low Ce tested steel, the inclusion of Al₂O₃ in the high Ce tested steel is significantly reduced, and most of the inclusion becomes the modified composite Ce aluminum oxygen inclusion. The decrease of the content of hard and brittle Al₂O₃ inclusions effectively improves the impact properties of the tested steel.

Key words: Ce, super duplex stainless steel, low temperature impact properties, ductile-brittle transition, modification of inclusion

CLC Number:

TG142

Bao Shun, Liu Rongpei, Wang Baoshun, Wu Minghua, Luo Youxin, Yao Liang, Feng Han, Song Zhigang. Effect of cerium additive on low temperature impact properties of S32750 super duplex stainless steel[J]. Heat Treatment of Metals, 2021, 46(11): 42-47.

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