摘要
采用应力比R=-1的拉压高周疲劳实验,研究了汽轮机焊接模拟转子试样的高周疲劳裂纹的萌生与扩展过程,并通过扫描电子显微镜(SEM)和能谱(EDS)观察与分析了疲劳断口的形貌特征和微区成分。结果表明:疲劳裂纹常在夹杂物和气孔等缺陷处萌生,进而以此为裂纹源,逐渐发生扩展,直至材料最终断裂失效。对于30Cr2Ni4MoV转子钢,夹杂物性质主要为氧化物(如CaO、SiO_2、Al_2O_3和MgO等),因此应严格控制钢中O、Al、Si、Mg、Ca等元素的含量。
The initiation and propagation of fatigue crack of the simulation rotor used in steam turbine was investigated by employing the repeated high cycle tension and compression test with stress ratio R = - 1. The fatigue fracture morphology was observed by the scanning electron microscope （ SEM）, and the composition was analyzed by the energy dispersive spectroscopy （EDS）. The results showed that the fatigue crack was initiated in the zone where inclusion and/or pores existed, and then the fatigue crack propagated until its fracture failure. In particular, the inclusions in 30Cr2Ni4MoV rotor steel mainly consisted of oxides such as CaO, SiO2, Al2O3 and MgO etc. So the content of O, Al,Si,Mg and Ca element in rotor steel should be controlled strictly.
出处
《上海金属》
CAS
北大核心
2013年第2期17-21,26,共6页
Shanghai Metals
关键词
转子钢
焊接接头
高周疲劳
疲劳断口
夹杂物
Rotor Steel, Welded Joint, High Cycle Fatigue, Fatigue Fracture, Inclusion
