Gigacycle Fatigue Behavior of 1800 MPa Grade High Strength Spring Steel for Automobile Lightweight  

作　　者：Ji-ming ZHANG Ling-kang JI Dong-jie BAO Yao-rong FENG Shou-xin LI Yu-qing WENG 

机构地区：[1]CNPC Tubular Goods Research Institute [2]Xingtai Polytechnic College [3]Institute of Metal Research,Academy of Sciences [4]Central Iron and Steel Research Institute

出　　处：《Journal of Iron and Steel Research International》2014年第6期614-618,共5页

基　　金：Sponsored by National Basic Research Program(973 Program)of China(2004CB619100)

摘　　要：Gigacycle fatigue behavior of 60Si2CrVA high strength spring steel was investigated by ultrasonic fatigue test machine. Fatigue fractography was observed by scanning electron microscopy （SEM）. Maximum inclusion sizes and fatigue strength in different volumes were estimated by statistics of extreme values （SEV） and generalized Pareto distribution （GPD） methods. The results showed that S N curves of 60Si2CrVA spring steels for two rolling processes were not horizontal asymptotes but a gradient in a regime of 109 cycles, and traditional fatigue limits were eliminated. Surface machined topography and inclusions in steel were major factors that led to elimination of fatigue limit for 60Si2CrVA spring steel. The SEV and GPD methods could effectively predict size of the maximum inclusion and fatigue strength in different volumes of 60Si2CrVA spring steel. Predicted fatigue strength was in accordance with experimental results by ultrasonic fatigue testing.Gigacycle fatigue behavior of 60Si2CrVA high strength spring steel was investigated by ultrasonic fatigue test machine. Fatigue fractography was observed by scanning electron microscopy （SEM）. Maximum inclusion sizes and fatigue strength in different volumes were estimated by statistics of extreme values （SEV） and generalized Pareto distribution （GPD） methods. The results showed that S N curves of 60Si2CrVA spring steels for two rolling processes were not horizontal asymptotes but a gradient in a regime of 109 cycles, and traditional fatigue limits were eliminated. Surface machined topography and inclusions in steel were major factors that led to elimination of fatigue limit for 60Si2CrVA spring steel. The SEV and GPD methods could effectively predict size of the maximum inclusion and fatigue strength in different volumes of 60Si2CrVA spring steel. Predicted fatigue strength was in accordance with experimental results by ultrasonic fatigue testing.

关 键 词：gigacycle fatigue S-N curve FRACTOGRAPHY FISH-EYE INCLUSION statistics of extreme value （SEV） generalized Pareto distribution （GPD） 

分 类 号：TG115.5[金属学及工艺—物理冶金]