10Ni5CrMoV钢双轴弯曲应力下表面裂纹疲劳扩展特性研究

Study on Fatigue Surface Crack Propagation of 10Ni5CrMoV Steel under Biaxial Bending Stress

以10Ni5CrMoV钢为研究对象,在加载条件与构件使用环境相近条件下,在原板厚大尺寸试样表面引入人工缺口模拟实际构件中存在的类表面裂纹缺陷,采用双轴弯曲疲劳试验方法,开展原板厚大尺寸试样双轴弯曲应力下的表面裂纹疲劳扩展特性试验研究。结果表明,裂纹半长c和裂纹深度a都随循环次数N单调递增,且曲线a-N满足一定的线性关系。建立表面裂纹半长c与深度a之间的定量关系式预测模型,从而定量解决裂纹深度尺寸不好直接测量的难题。

The experimental research on fatigue surface crack propagation of thick and large specimen of 10Ni5CrMoV steel under biaxial-bending stress was carried out using the biaxial bending fatigue test method when the testing environment was similar to the real service one. Besides,the artificial crack source notch was introduced into the surface of the circular plate to simulate the surface crack defects existing in the actual component. It was indicated that the crack half length c and the crack depth a increased with the number of cycles N monotonically,and the curve of a-N presented a certain linear relationship; the prediction model between the the surface crack half-length c and the depth a was established,so that the problem that the depth of crack couldn＇t be measured directly could be solved quantitatively.