微小サンプル採取が配管のクリープ寿命に及ぼす影響の評価

抄録

An influence of miniature sample scoop on creep life of ASME Grade 91 steel piping was experimentally assessed in this work. Internal pressure tests were conducted on tubular type specimens having defects on outer surface of the materials, which simulate the sampling scoop. When a depth ratio of the defect to a wall thickness of the specimen is about 17%, creep life decreased to 2/3 of that of no defect specimen. On the other hand, no creep life reduction was observed on the specimen of the depth ratio 5%, while stress concentration around the defect was revealed by FE analysis. The result suggested that the miniature sample up to 5% of the thickness direction of pipings scarcely has the influence on the creep life of the Grade 91 steel pipings.