N80Q钢的高温低周疲劳行为及寿命预测  

High Temperature Low Cycle Fatigue Behavior and Life Prediction of N80Q Steel

作　　者：崔璐[1] 杨程晖 魏文澜 吴鹏 程嘉瑞[1] 曹银萍[1] CUI Lu;YANG Chenghui;WEI Wenlan;WU Peng;CHENG Jiarui;CAO Yinping(School of Mechanical Engineering,Xi’an Shiyou University,Xi'an 710072,China)

机构地区：[1]西安石油大学机械工程学院,陕西西安710072

出　　处：《热加工工艺》2022年第20期29-33,共5页Hot Working Technology

基　　金：国家自然科学基金资助项目(51901180);国家自然科学基金资助项目(51305348);国家重点研发计划项目(2019YFF0217504)。

摘　　要：在350℃下对N80Q钢在应变幅为0.5%、0.7%、1.0%、1.5%、2.0%下进行低周疲劳试验,分析了其低周疲劳行为。结果表明:塑性应变幅与疲劳寿命的关系和塑性应变幅与循环应力幅的关系在对数坐标系下均呈线性关系。用Manson-Coffin方程和Basquin方程的叠加能较好的预测350℃下N80Q钢应变与低周疲劳寿命的关系。N80Q钢低周疲劳主要断裂方式为韧脆交替的周期性解理断裂,疲劳裂纹源均在试样的表面处,低应变条件下更易形成多裂纹源萌生。随着总应变幅的增加,裂纹扩展区的二次裂纹长度增大。The low cycle fatigue test of N80Q steel was carried out at 350℃under the condition of strain amplitude of 0.5%,0.7%,1.0%,1.5%and 2.0%,and the low cycle fatigue behavior was analyzed.The results show that the plastic strain amplitude and fatigue life,plastic strain amplitude and cyclic stress amplitude are in linear logarithmic coordinate system.The superposition of Manson coffin equation and basquin equation can well predict the relationship between strain and low cycle fatigue life of N80Q steel at 350℃.The main fracture mode of low cycle fatigue of N80Q steel is periodic cleavage fracture with alternate toughness and brittleness.The fatigue crack sources are all on the surface of the sample,and it is easier to form multiple crack sources under low strain condition.With the increase of the total strain amplitude,the length of the secondary crack in the crack growth zone increases significantly.

关 键 词：套管钢 高温低周疲劳 疲劳寿命 疲劳断口 

分 类 号：TG115.5[金属学及工艺—物理冶金]