摘要 |
PURPOSE:To measure nondestructively the remaining service life of a body to be inspected by measuring the high-temp. hardness of said body and setimating the remaining service life basing on the hardness. CONSTITUTION:At measurement, at first, a prescribed position of a welded part 2 of a heat transfer tube 5 which is a measuring object is selected, oxide scales at the part are removed by a grinder, etc., then said part is heated up to the temp. attainable during boiler operation by a heater 3, and attains to a prescribed temp., the hardness at the temp. is measured by a hardness tester 4. By using a characteristic figure, if exchanging is necessary in case the high temp. hardness becomes h2 and the material hardness measured actually is denoted as h1 (rupture at time t2), since the boiler operation time elapsing until the hardness h2 necessitating the exchanging is attained is T3 and the time elapsing until said hardness h1 is attained is T2, the remaining service life of the material having the hardness h1 is calculated as T3-T2. |