1987 年 51 巻 3 号 p. 187-193
The fatigue crack growth behavior of roll clad steel plate, overlaying clad steel plate, and SM41B, 2\frac14Cr-1Mo steel plates was investigated by use of the surface crack specimens. The fracture surface of these plates was also analyzed quantitatively by using the fractographic method.
The results obtained are summarized as follows.
(1) For both roll and overlaying clad steels, the fatigue crack growth rate, db/dN, retarded slightly near the clad interface.
(2) The intergranular facet was observed on the fracture surface of SM41B and base metals of roll clad steel and overlaying clad steel. In all cases, the shape of its observed region was half elliptical.
(3) The stress intensity factor ranges, ΔKb and db/dN, at the location where the intergranular facet disappeared were nearly constant for SM41B and roll clad steel.