Effect of microstructure evolution on strength and impact toughness of G18CrMo2-6 heat-resistant steel during tempering

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	Effect of microstructure evolution on strength and impact toughness of G18CrMo2-6 heat-resistant steel during tempering
	Z. J. Li; N. M. Xiao; D. Z. Li; J. Y. Zhang; Y. J. Luo; R. X. Zhang
	2014
发表期刊	Materials Science and Engineering a-Structural Materials Properties Microstructure and Processing
ISSN	0921-5093
卷号	604 页码:103-110
摘要	G18CrMo2-6 steel is one kind of low alloy CrMo steel with ferrite/bainite phase constituent. It is widely adopted in the large casting parts of pressure vessels. This paper aims at investigating evolution of G18CrMo2-6 steel microstructure, tensile strength and impact toughness during the tempering (680 degrees C). The tempered microstructure characterization shows that the tempering time mainly affects the precipitation of three kinds of carbides, naming MC, M3C and M23C6. Both tensile strength and impact toughness do not obey the monotonic evolution with the tempering time but the complex changes. The shift of mechanical properties results from the interaction among matrix phases and the evolution of three different kinds of carbides. The softening of matrix due to the dislocation recovery and the decrease of the amout of carbon and other alloy elements in matrix lattice due to the precipitation of M23C6 cause the decreasing tensile strength for the whole tempering except for that an increase during the short-term tempering controlled by the precipitation of MC and the spheroidization and refinement of M3C carbide. On the other hand, both the softening of matrix and the spheroidization and refinement of M3C carbide are responsible for the increasing impact toughness. However, the precipitation and coarsening of M23C6 at ferrite grain boundaries during long-term tempering results in the sharp deterioration of impact toughness. It attributes to the larger grain boundary carbides result in the lower critical fracture stress of a carbide-ferrite interface. (C) 2014 Elsevier B.V. All rights reserved.
部门归属	[li, zhenjiang ; xiao, namin ; li, dianzhong] chinese acad sci, inst met res, shenyang natl lab mat sci, shenyang 110016, peoples r china. [zhang, junyong ; luo, yongjian ; zhang, ruixue] kocel grp co ltd, yinchuan 750021, peoples r china. ; xiao, nm (reprint author), chinese acad sci, inst met res, shenyang natl lab mat sci, 72 wenhua rd, shenyang 110016, peoples r china. ; 08121881@bjtu.edu.cn
关键词	Tempering Precipitation Tensile Strength Impact Toughness Carbides Low-alloy Steels Grain-boundary Segregation High-temperature Exposure Affected Zone 2.25cr-1mo Steel Bainitic Steels Martensite Embrittlement Cooling Conditions Precipitation Carbides
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语种	英语
文献类型	期刊论文
条目标识符	http://ir.imr.ac.cn/handle/321006/72876
专题	中国科学院金属研究所
推荐引用方式 GB/T 7714	Z. J. Li,N. M. Xiao,D. Z. Li,et al. Effect of microstructure evolution on strength and impact toughness of G18CrMo2-6 heat-resistant steel during tempering[J]. Materials Science and Engineering a-Structural Materials Properties Microstructure and Processing,2014,604:103-110.
APA	Z. J. Li,N. M. Xiao,D. Z. Li,J. Y. Zhang,Y. J. Luo,&R. X. Zhang.(2014).Effect of microstructure evolution on strength and impact toughness of G18CrMo2-6 heat-resistant steel during tempering.Materials Science and Engineering a-Structural Materials Properties Microstructure and Processing,604,103-110.
MLA	Z. J. Li,et al."Effect of microstructure evolution on strength and impact toughness of G18CrMo2-6 heat-resistant steel during tempering".Materials Science and Engineering a-Structural Materials Properties Microstructure and Processing 604(2014):103-110.