水素圧縮機の破損解析

抄録

Failure analysis of hydrogen compressor (hydrogen pressure : 20 MPa, number of cycles to failure : 6.1×10⁶ cycles) was conducted. Chemical composition analysis, Microstructure observation, tensile test and Vickers hardness measurement showed that the material used was SCM440H which was sound. SEM observation of fracture surface showed that the connection part of hydrogen compressor was fatigue-failured. The maximum stress σ_max = 573 MPa of cyclic loading was estimated from fracture toughness K_IC = 199 MPa・m^1/2 for SCM435. It was inferred from the maximum stress σ_max = 573 MPa and S-N diagram (stress ratio R = 0) of SCM440 that the connection part was fatigue failured at the number of cycles to failure N_f = 6.1×10⁶ cycles.