Low Circle Fatigue Behavior of X80 High-Strain Line pipe

摘要：

　　Symmetrical push-pull low circle fatigue tests have been performed on high-strain X80 line pipe material.Micro-analysis has been performed for deformation mechanism as well.Results show that X80 high-strain line pipe material exhibited a higher ductility and long low-circle fatigue life.Cyclic softening is observed at low strain amplitude of 0.4% and 0.6%,however,cyclic softening occurred after slight cyclic hardening at high strain amplitude of 1.0%,1.2% and 1.4%.Generally,Cyclic response curves show that the cyclic softening occurred at all strains amplitude (0.4%~1.4%).Fractography analysis suggests that transgranular fracture with well-developed fatigue striations and obvious second crack is the predominant failure mode.The amount of second cracks is much fewer deformed in high-strain X80 line pipe material than that in conventional X80 line pipe material.TEM examination reveals that the primary deformation mode of two kinds of material was dislocation slipping.Abundant dislocation glide bands and dislocation cells are formed at grain boundary as strain amplitude increased.Deformation in ferrite has been suppressed and formation of dislocation cell inside the ferrite has been postponed due to large content of M/A constituent.

关键词： High-strain line pipe Low-circle fatigue Strain amplitude Dislocation M/A

作者: Yang Li Weiwei Zhang Lingkang Ji Qingren Xiong Yaorong Feng Chunyong Huo

作者单位: Master, CNPC Tubular Goods Research Institute, No.32 Dianzier Road, Xian, China, 710065 Doctor, CNPC Tubular Goods Research Institute, No.32 Dianzier Road, Xian, China, 710065

会议类型: 国际会议

会议名称: 第四十届国际海事委员会会议

会议地点: 北京

会议语种:英文

页码: 783-793

在线出版日期: 2012-10-14（万方平台首次上网日期，不代表论文的发表时间）