Effect of Cooling Rate on Microstructure and Effective Grain Size for a Ni-Cr-Mo-B High-Strength Steel

doi:10.1007/s40195-022-01422-6

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	Effect of Cooling Rate on Microstructure and Effective Grain Size for a Ni-Cr-Mo-B High-Strength Steel
	Zhang, Shouqing 1,2; Hu, Xiaofeng 2; Jiang, Haichang 2; Rong, Lijian 2
刊名	ACTA METALLURGICA SINICA-ENGLISH LETTERS
	2022-06-16
页码	11
关键词	Ni-Cr-Mo-B steel Cooling rate Microstructural characterization Effective grain size (EGS)
ISSN号	1006-7191
DOI	10.1007/s40195-022-01422-6
通讯作者	Hu, Xiaofeng(xfhu@imr.ac.cn) ; Rong, Lijian(ljrong@imr.ac.cn)
英文摘要	The effect of cooling rate on microstructure and effective grain size (EGS) of a Ni-Cr-Mo-B high-strength steel has been studied by dilatometer, field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and electron backscattered diffraction (EBSD). The results show that the microstructure of the Ni-Cr-Mo-B steel is dependent on cooling rate in the following sequence: lath martensite (LM), mixed LM and lath bainite (LB), mixed LB and granular bainite (GB) and GB. The critical cooling rates for appearance of LB and GB are about 10 degrees C/s and 0.5 degrees C/s, respectively. The LM (> 10 degrees C/s) consists of few blocky regions with a width of several micros. Compared with the lath regions, the blocky regions in LM form at higher actual transformation temperatures during cooling. The blocky region area percentage in LM keeps almost constant about 8% at different cooling rates (> 10 degrees C/s) due to similar martensite transformation starting temperature (M-s). The LB percentage in mixed LM/LB increases gradually with decreasing cooling rate (10-0.5 degrees C/s). The EBSD results show that different microstructures have different EGS. The mixed LM/LB exhibits the smallest EGS due to the separation of the prior austenite grains by the pre-formed LB and the refinement of the LM. Meanwhile, the mixed LM/LB at different cooling rates (10-0.5 degrees C/s) exhibits almost the same EGS because the LB and LM in the mixed LM/LB have a similar high-angle grain boundary density and similar EGS. Because the blocky regions contain few high-angle grain boundaries and have similar area percentages in the LM, the LM at different cooling rates (> 10 degrees C/s) exhibits almost the same EGS. The ferrite in GB exhibits as a whole with few high-angle grain boundaries; thus, the mixed LB/GB exhibits the largest EGS.
资助项目	Liaoning Revitalization Talents Program[XLYC1907143] ; Strategic Priority Research Program of the Chinese Academy of Sciences[XDC04000000] ; Strategic Priority Research Program of the Chinese Academy of Sciences[XDA28040200]
WOS研究方向	Metallurgy & Metallurgical Engineering
语种	英语
出版者	CHINESE ACAD SCIENCES, INST METAL RESEARCH
WOS记录号	WOS:000811965600001
资助机构	Liaoning Revitalization Talents Program ; Strategic Priority Research Program of the Chinese Academy of Sciences
内容类型	期刊论文
源URL	[http://ir.imr.ac.cn/handle/321006/174338]
专题	金属研究所_中国科学院金属研究所
通讯作者	Hu, Xiaofeng; Rong, Lijian
作者单位	1.Univ Sci & Technol China, Sch Mat Sci & Engn, Shenyang 110016, Peoples R China 2.Chinese Acad Sci, Inst Met Res, CAS Key Lab Nucl Mat & Safety Assessment, Shenyang 110016, Peoples R China
推荐引用方式 GB/T 7714	Zhang, Shouqing,Hu, Xiaofeng,Jiang, Haichang,et al. Effect of Cooling Rate on Microstructure and Effective Grain Size for a Ni-Cr-Mo-B High-Strength Steel[J]. ACTA METALLURGICA SINICA-ENGLISH LETTERS,2022:11.
APA	Zhang, Shouqing,Hu, Xiaofeng,Jiang, Haichang,&Rong, Lijian.(2022).Effect of Cooling Rate on Microstructure and Effective Grain Size for a Ni-Cr-Mo-B High-Strength Steel.ACTA METALLURGICA SINICA-ENGLISH LETTERS,11.
MLA	Zhang, Shouqing,et al."Effect of Cooling Rate on Microstructure and Effective Grain Size for a Ni-Cr-Mo-B High-Strength Steel".ACTA METALLURGICA SINICA-ENGLISH LETTERS (2022):11.