Change of critical event for cleavage fracture of HSLA steel | |
Chen, J.H.; Wang, G.Z. | |
2005 | |
会议日期 | March 20, 2005 - March 25, 2005 |
会议地点 | Turin, Italy |
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 |
卷号 | 6 |
页码 | 3980-3985 |
英文摘要 | 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. |
会议录 | 11th International Conference on Fracture 2005, ICF11
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会议录出版者 | International Congress on Fracture |
语种 | 英语 |
内容类型 | 会议论文 |
源URL | [http://ir.lut.edu.cn/handle/2XXMBERH/117177] ![]() |
专题 | 兰州理工大学 |
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 |
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]. 见:. Turin, Italy. March 20, 2005 - March 25, 2005. |
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