Change of critical event for cleavage fracture of HSLA steel

	Change of critical event for cleavage fracture of HSLA steel
	Chen, J.H.; Wang, G.Z.
	2005
会议名称	11th International Conference on Fracture 2005, ICF11
会议录名称	11th International Conference on Fracture 2005, ICF11
卷号	6
页码	3980-3985
会议日期	March 20, 2005 - March 25, 2005
会议地点	Turin, Italy
出版者	International Congress on Fracture
摘要	The greatest difficult step in the cleavage process presents in term of 'critical event'. In this paper results of series investigations on the critical event for cleavage of HSLA steel are presented. It reveals that basically the critical event for cleavage of notched specimens of HSLA steels at low temperature (lower than -130°C) is the 'propagation of a ferrite grain-sized crack'. The criterion for crack propagation can be presented by following formula σyy =Q σflow = Q(σ y+Δσy) ≥σf. Any variation, which makes above formula to be satisfied easier, may induce the change of critical event from propagation of a grain-sized crack to propagation of a second phase particle-sized crack and further to the crack nucleation. A precrack is more acute than a notch, thus it increases the stress intensification factor Q and σyy, which can propagate a second phase particle-sized crack even though it is much shorter than a grain-sized crack. Decreasing the test temperature and increasing the loading rate, both increase σy and make the term in the left side of above formula easier to reach the σf. The prestrain produces a increment of Δ σy by work hardening, which put the same effect as increasing σy. Increasing grain sizes acts from other hand to decrease σf, which also makes the formula to be satisfied easier. In essence, critical event can be transformed to the 'propagation of a second phase particle-sized crack' and further to the 'crack nucleation' by increasing the acuity of defects (in precracked specimen), coarsening the grain size, decreasing the test temperature, raising the loading rate, and subjecting specimens to pre-strain.
关键词	Coarsening Fracture Grain size and shape High-strength low-alloy steel Nucleation Strain hardening Temperature Cleavage fracture Crack nucleation Grain-sized crack Low temperatures Notched specimens Precracked specimens Second phase particles Test temperatures
收录类别	EI
语种	英语
EI入藏号	20124815728160
EI主题词	Cracks
来源库	Compendex
分类代码	537.1 Heat Treatment Processes - 641.1 Thermodynamics - 933.1.2 Crystal Growth - 951 Materials Science
文献类型	会议论文
条目标识符	https://ir.lut.edu.cn/handle/2XXMBERH/117177
专题	材料科学与工程学院_特聘教授组
作者单位	College of Materials Science and Engineering, State Key Laboratory for New Materials of Non-Ferrous Metal, Lanzhou University of Technology, Lanzhou, 730050, China
第一作者单位	兰州理工大学
推荐引用方式 GB/T 7714	Chen, J.H.,Wang, G.Z.. Change of critical event for cleavage fracture of HSLA steel[C]:International Congress on Fracture,2005:3980-3985.