A Study of Microstructure and Mechanical Properties for the Autogenous Single-Pass Butt Weldment of a Ferritic/Martensitic Steel Using Gas Tungsten Arc Welding

doi:10.1007/s40195-020-01146-5

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	A Study of Microstructure and Mechanical Properties for the Autogenous Single-Pass Butt Weldment of a Ferritic/Martensitic Steel Using Gas Tungsten Arc Welding
	Wu, Dong 2; Wei, Shitong 2; Lu, Shanping 1
刊名	ACTA METALLURGICA SINICA-ENGLISH LETTERS
	2020-10-26
页码	11
关键词	Martensitic stainless steel Gas tungsten arc welding (GTAW) Post-weld heat treatment Microstructure Mechanical properties
ISSN号	1006-7191
DOI	10.1007/s40195-020-01146-5
通讯作者	Lu, Shanping(shplu@imr.ac.cn)
英文摘要	A 12% Cr ferritic/martensitic steel, HT-9, has been used as a primary core material for nuclear reactors. The microstructure and mechanical properties of gas tungsten arc butt welded joints of HT-9 in as-welded, and as-tempered conditions have been explored. In as-welded condition, the fusion zone (FZ) contained a fresh martensite matrix with delta (delta)-ferrite. The delta-ferrite was rich in Cr and depleted in C compared with the matrix. The heat-affected zone (HAZ) could be divided into three areas as the distance from the fusion line increased: delta-ferrite/martensite duplex zone, fully recrystallized zone, and partly recrystallized zone. Prior austenitic grains did not coarsen in the delta-ferrite/martensite duplex zone due to the newly nucleated delta-ferrite grains and incompletely ferritizing (delta-ferrite) during the welding thermal cycle. The weldment microhardness distributed heterogeneously with values above 600 HV1.0 in the HAZ and FZ and 250 HV1.0 in the base metal (BM). Solute C in the matrix, induced by the dissolution of carbide during the welding process, dominated the microhardness variation. Low toughness was observed in the FZ with a quasi-cleavage fracture tested from - 80 to 20 degrees C. The tensile fracture occurred in the relatively soft BM tested from 20 to 600 degrees C. In as-tempered condition (760 degrees C for 1 h), M23C6-type carbides precipitated within the martensitic laths, the lath boundaries, and the delta-ferrite/martensite interfaces. Moreover, V, Cr, Mo-rich nitrides with very small size also precipitated in the delta-ferrite/martensite interface. The tempering treatment improved the homogenous distribution of weldment hardness significantly. Tensile fracture still occurred in the BM of the weldment specimens tested from 20 to 600 degrees C. The impact toughness improved significantly, but the ductile-brittle transaction temperature was - 12 degrees C which was higher than that of the normalized and tempered (N&T) BM. delta-ferrite was considered to be one of the major factors aggravating the impact toughness in the FZ.
资助项目	China National Nuclear Corporation-Chinese Academy of Sciences Joint Key Laboratory of Nuclear Material and Safety Assessment
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:000583963000001
资助机构	China National Nuclear Corporation-Chinese Academy of Sciences Joint Key Laboratory of Nuclear Material and Safety Assessment
内容类型	期刊论文
源URL	[http://ir.imr.ac.cn/handle/321006/141137]
专题	金属研究所_中国科学院金属研究所
通讯作者	Lu, Shanping
作者单位	1.Chinese Acad Sci, Inst Met Res, Shenyang Natl Lab Mat Sci, 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	Wu, Dong,Wei, Shitong,Lu, Shanping. A Study of Microstructure and Mechanical Properties for the Autogenous Single-Pass Butt Weldment of a Ferritic/Martensitic Steel Using Gas Tungsten Arc Welding[J]. ACTA METALLURGICA SINICA-ENGLISH LETTERS,2020:11.
APA	Wu, Dong,Wei, Shitong,&Lu, Shanping.(2020).A Study of Microstructure and Mechanical Properties for the Autogenous Single-Pass Butt Weldment of a Ferritic/Martensitic Steel Using Gas Tungsten Arc Welding.ACTA METALLURGICA SINICA-ENGLISH LETTERS,11.
MLA	Wu, Dong,et al."A Study of Microstructure and Mechanical Properties for the Autogenous Single-Pass Butt Weldment of a Ferritic/Martensitic Steel Using Gas Tungsten Arc Welding".ACTA METALLURGICA SINICA-ENGLISH LETTERS (2020):11.