抄録
Small punch (SP) creep test with TEM disk-size specimen (φ3mm, t 0.25mm) was applied to the aged boiler tube (STBA24), which had been used in excess of 140,000 hours, to investigate the distribution of material degradation and/or damage in the thin tube wall. Experimental results revealed that there was no significant difference between the creep properties of specimens removed from the inside and the outside of thin wall, and the material degradation and/or damage had been accumulated uniformly. Additionally, it was also revealed that the SP creep rupture data might be converted into uniaxial data by the average equivalent stress in steady state, σ_S, which has been newly proposed by the authors.
