Effect of δ-Ferrite on Hot Deformation and Recrystallization of 316KD Austenitic Stainless Steel for Sodium-Cooled Fast Reactor Application

doi:10.11900/0412.1961.2022.00039

IMR OpenIR

	Effect of δ-Ferrite on Hot Deformation and Recrystallization of 316KD Austenitic Stainless Steel for Sodium-Cooled Fast Reactor Application
	Chen Shenghu 1; Wang Qiyu 1,2; Jiang Haichang 1; Rong Lijian 1
通讯作者	Rong Lijian(ljrong@imr.ac.cn)
	2024-03-01
发表期刊	ACTA METALLURGICA SINICA
ISSN	0412-1961
卷号	60 期号:3 页码:367-376
摘要	The sodium-cooled fast reactor is the most mature reactor among generation-IV nuclear reactors. A carbon/nitrogen-controlled 316KD austenitic stainless steel has been developed for the construction of pressure vessels and internals in Chinese CFR600 demonstration reactor. During their industrial production, d -ferrite is present in large-scale billets because of the combined effect of non-equilibrium segregation and low cooling rate. For large-scale billets containing d -ferrite, inhomogeneous grain-size distributions are observed in the product after hot working. Extensive studies on the recrystallization of the austenite phase in austenitic stainless steels during hot deformation were conducted. However, the effect of d -ferrite on the recrystallization behavior of the austenite phase remains unclear. In this study, uniaxial hot compression tests of 316KD austenitic stainless steels involving as-cast and homogenized conditions were conducted at 1423 K and 0.1 s- 1 using a Gleeble-3800 thermal-mechanical simulator, and the effect of d- ferrite on hot deformation and recrystallization was analyzed by SEM, EBSD, and TEM. Results showed that d- ferrite could be nearly eliminated through d- ferrite. austenite transformation after homogenization at 1473 K for 14 h, whereas austenite grain showed evident growth. The elimination of d- ferrite was a Cr-diffusion-controlled process through kinetic analysis. Plastic deformation occurred preferentially in d- ferrite and at the d- ferrite/austenite interface, and subsequently in austenite during hot deformation. The flow stress of as-cast samples was much lower than that of homogenized samples at the same strain because of the presence of soft d- ferrite. Dynamic recovery occurred easier in d-ferrite, and the resulting dynamic softening remarkably reduced flow stress with an increase in strain. Discontinuous dynamic recrystallization characterized by original austenite grain boundary bulging was the dominant mechanism in homogenized samples. However, the presence of d- ferrite promoted the occurrence of continuous dynamic recrystallization in austenite near the d- ferrite/austenite interface in ascast samples. Compared with the homogenized samples, a higher degree of recrystallization was observed in as-cast samples because of the combined effects of continuous dynamic recrystallization and discontinuous dynamic recrystallization.
关键词	austenitic stainless steel delta-ferrite homogenization treatment hot deformation dynamic recrystallization
DOI	10.11900/0412.1961.2022.00039
收录类别	SCI
语种	英语
WOS研究方向	Metallurgy & Metallurgical Engineering
WOS类目	Metallurgy & Metallurgical Engineering
WOS记录号	WOS:001193645500009
出版者	SCIENCE PRESS
引用统计
文献类型	期刊论文
条目标识符	http://ir.imr.ac.cn/handle/321006/185259
专题	中国科学院金属研究所
通讯作者	Rong Lijian
作者单位	1.Chinese Acad Sci, Inst Met Res, CAS Key Lab Nucl Mat & Safety Assessment, Shenyang 110016, Peoples R China 2.Univ Sci & Technol China, Sch Mat Sci & Engn, Shenyang 110016, Peoples R China
推荐引用方式 GB/T 7714	Chen Shenghu,Wang Qiyu,Jiang Haichang,et al. Effect of δ-Ferrite on Hot Deformation and Recrystallization of 316KD Austenitic Stainless Steel for Sodium-Cooled Fast Reactor Application[J]. ACTA METALLURGICA SINICA,2024,60(3):367-376.
APA	Chen Shenghu,Wang Qiyu,Jiang Haichang,&Rong Lijian.(2024).Effect of δ-Ferrite on Hot Deformation and Recrystallization of 316KD Austenitic Stainless Steel for Sodium-Cooled Fast Reactor Application.ACTA METALLURGICA SINICA,60(3),367-376.
MLA	Chen Shenghu,et al."Effect of δ-Ferrite on Hot Deformation and Recrystallization of 316KD Austenitic Stainless Steel for Sodium-Cooled Fast Reactor Application".ACTA METALLURGICA SINICA 60.3(2024):367-376.