Improvement of Strength-Toughness-Hardness Balance in Large Cross-Section 718H Pre-Hardened Mold Steel

doi:10.3390/ma11040583

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	Improvement of Strength-Toughness-Hardness Balance in Large Cross-Section 718H Pre-Hardened Mold Steel
	Liu, HH ; Fu, PX ; Liu, HW ; Li, DZ
刊名	MATERIALS
	2018-04-01
卷号	11 期号:4 页码:-
关键词	718H pre-hardened mold steel heat treatments strength-toughness-hardness microstructure
ISSN号	1996-1944
DOI	10.3390/ma11040583
英文摘要	The strength-toughness combination and hardness uniformity in large cross-section 718H pre-hardened mold steel from a 20 ton ingot were investigated with three different heat treatments for industrial applications. The different microstructures, including tempered martensite, lower bainite, and retained austenite, were obtained at equivalent hardness. The microstructures were characterized by using metallographic observations, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and electron back-scattered diffraction (EBSD). The mechanical properties were compared by tensile, Charpy U-notch impact and hardness uniformity tests at room temperature. The results showed that the test steels after normalizing-quenching-tempering (N-QT) possessed the best strength-toughness combination and hardness uniformity compared with the conventional quenched-tempered (QT) steel. In addition, the test steel after austempering-tempering (A-T) demonstrated the worse hardness uniformity and lower yield strength while possessing relatively higher elongation (17%) compared with the samples after N-QT (14.5%) treatments. The better ductility of A-T steel mainly depended on the amount and morphology of retained austenite and thermal/deformation-induced twined martensite. This work elucidates the mechanisms of microstructure evolution during heat treatments and will highly improve the strength-toughness-hardness trade-off in large cross-section steels.
学科主题	Materials Science, Multidisciplinary
语种	英语
WOS记录号	WOS:000434710200125
内容类型	期刊论文
源URL	[http://ir.imr.ac.cn/handle/321006/80216]
专题	金属研究所_中国科学院金属研究所
作者单位	1.Chinese Acad Sci, Inst Met Res, 72 Wenhua Rd, Shenyang 110016, Peoples R China 2.Univ Sci & Technol China, Sch Mat Sci & Engn, 72 Wenhua Rd, Shenyang 110016, Peoples R China
推荐引用方式 GB/T 7714	Liu, HH,Fu, PX,Liu, HW,et al. Improvement of Strength-Toughness-Hardness Balance in Large Cross-Section 718H Pre-Hardened Mold Steel[J]. MATERIALS,2018,11(4):-.
APA	Liu, HH,Fu, PX,Liu, HW,&Li, DZ.(2018).Improvement of Strength-Toughness-Hardness Balance in Large Cross-Section 718H Pre-Hardened Mold Steel.MATERIALS,11(4),-.
MLA	Liu, HH,et al."Improvement of Strength-Toughness-Hardness Balance in Large Cross-Section 718H Pre-Hardened Mold Steel".MATERIALS 11.4(2018):-.