摘要
用超声疲劳试验技术研究40CrNiMo钢表面处理在超声振动载荷(f=20kHz,R=-1)下的疲劳寿命以及影响因素。研究结果表明,渗碳和渗氮处理能显著提高工件的超声疲劳寿命,此外具有强韧配合的微观组织超声疲劳寿命较高。研究发现,40CrNiMo钢不同类型的微观组织具有两种类型的S-N曲线,即持续下降型和阶梯下降型。扫描电镜对疲劳断口进行分析表明,超声疲劳载荷下,裂纹在试样表面或次表面缺陷处萌生,然后向里扩展。
The fatigue life of 40CrNiMo steel treated by different technologies under ultrasonic fatigue loading (f = 20 kHz, R = -1) and its influencing factors were studied using a ultrasonic fatigue testing machine. The results show that the ultrasonic fatigue life of the specimen is markedly increased by carbonization and nitridation. The longer fatigue life of specimens with microstructures characterized by proper combination of both strength and toughness is observed. 40CrNiMo steel with different microstructure exhibit two types of S-N curve: a continuously decreasing curve and a stepwise curve. The fatigue fracture surface was analyzed by scanning electron microscopy. The results show that fatigue crack initiated at defects of specimen surface or sub-surface of specimen under surface at the ultrasonic fatigue loading and then the crack propagated towards inside of the specimens.
出处
《材料热处理学报》
EI
CAS
CSCD
北大核心
2006年第4期65-68,共4页
Transactions of Materials and Heat Treatment
基金
江苏省教育厅自然基金项目(03KJB430026)
关键词
超声疲劳
疲劳寿命
表面处理
40CRNIMO钢
Carbonization
Cracks
Fatigue of materials
Fatigue testing
Fracture
Microstructure
Nitriding
Scanning electron microscopy
Surface treatment
Toughness
Ultrasonic testing
