文献类型：期刊文献

英文题名：Effect of the out-of-plane constraint on creep crack growth property of Cr-Mo-V type steel

作者：Tan, Jian-Ping[1]; Wang, Guo-Zhen[1]; Xuan, Fu-Zhen[1]; Tu, Shan-Tung[1]; Wang, Zheng-Dong[1]

机构：[1] Key Laboratory of Safety Science of Pressurized System, East China University of Science and Technology, Ministry of Education, Shanghai, China

年份：2011

卷号：5

起止页码：237

外文期刊名：American Society of Mechanical Engineers, Pressure Vessels and Piping Division (Publication) PVP

收录：EI(收录号：20133416626708)

语种：英文

外文关键词：Creep - Pressure vessels - Chromium alloys - Grain boundaries - Ternary alloys - Molybdenum alloys - Strain - Crack propagation - Grain growth - Molybdenum compounds

摘要：In order to establish an accurate integrity assessment of structures containing defects at high temperature, it is necessary to clarify the constraint effect on creep crack growth (CCG) property. However, the effect of the out-of-plane creep constraint induced by the specimen thicknesses has been little studied. In this study, the CCG properties and fracture mechanism of Cr-Mo-V type steel at 566°C were investigated by using the compact tension specimens with different thicknesses. The results show that the data of the CCG rate da/dt versus C* lie within a relatively tight scatter band on loglog scale for the specimens with different thicknesses at higher values of C*. In addition, the differences of CCG rate becomes large with C* decreasing. It means that the effect of out-ofplane constraint on CCG rate is dependent on the load level (C*). The reason for the similar CCG rate is that the creep damage and fracture mechanism of void growth at grain boundary ahead of crack tips in the specimens with different thicknesses does not essentially change. The size rc of the creep damage and fracture process zone in front of crack tips is related to the specimen thickness, and the damage rate fields over the process zone are similar for the specimens with different thicknesses. The deformation near the crack tip obscures the constraint effect. Based on a reference stress field under plane strain state and the creep process zone rc, in-plane and out-of-plane constraint parameter Rd and Td were defined and the creep crack-tip constraint effect induced by specimen thickness were quantitatively examined. The factors of creep time and load level (C*) influencing the constraint effect were analyzed. Copyright ? 2011 by ASME.