抄録
As a method of estimating the creep damage of alloys in service, the void formation in the microstructure of centrifugal cast alloys (HK 40 and HP) was investigated. The results obtained are summarized as follows:
(1) A quantitative indication of creep void formation can be made by taking the void area percent based on the point count method (JIS G 0555).
(2) The relationship between the void area percentage and the creep damage percentage is linear throughout the secondary and tertiary creep stages.
(3) In the case where a tube is subjected to bending stress, the creep damage in the tube wall cross-section can be related to the distribution of the creep void area percentage.
(4) The examination of actual alloys in service for creep damage by the present creep void formation method gave almost the same results as those obtained by the usual creep rupture test.
