摘要
以球墨铸铁QT400-15为研究对象,研究上限温度在600~900℃范围内时其热疲劳裂纹的萌生和扩展行为。结果表明,热疲劳裂纹主要是在石墨与基体交界处或交界处附近萌生,氧化对裂纹的萌生和扩展起辅助作用。主裂纹从人工缺口出发,通过环形裂纹带、楔形或者条形裂纹与沿线裸露或者浅埋石墨连接,从而形成长裂纹。石墨的不圆整以及线性排列、上限温度超过共析转变温度均加速裂纹的萌生和扩展。
The initiation and propagation behavior of thermal fatigue crack in nodular cast iron QT400-15 were studied by thermal fatigue test at upper limit temperature 600~900 ℃. The results show that the thermal fatigue cracks mainly initiate at or near the boundary between the graphite and the matrix, and the oxidation has an auxiliary effect on the initiation and propagation of the crack. The main crack starts from the artificial gap, connect the bare or near surface graphite along the line by the circular crack belt and strip or wedge crack to form a long crack. The non-circularity and linear array of graphite, and the crack initiation and propagation will accelerate when the upper limit temperature is higher than eutectic point.
出处
《铸造技术》
CAS
2018年第2期428-432,共5页
Foundry Technology
基金
河南省科技发展计划(162102210285)
关键词
球墨铸铁
热疲劳裂纹
萌生
扩展
nodular cast iron
thermal fatigue crack
initiation
propagation
