Restoration of metal service properties using repeated heat treatment

The available data are reviewed on the problem of restoration of service properties in structural meterials using repeated heat treatment. The possibility of healing of defects and restoration of structure and mechanical properties in pearlitic(12MKh, 12Kh1MF, 15Kh1MF), austenitic (1Kh18N12T, Kh20N25B) steels, and nickel alloys (EhJ437A, N80Kh20 etc.) is discussed. A conclusion is made that full restoration of the properties, a heat resistance for example, is possible in case of a creep rate three times as much as a secondary creep rate by the time the re-heat treatment is conducted. This value is considered to be a critical one for transition from reversible to non-reversible damage