抄録
The stress corrosion crack growth behavior of sensitized Type 304 stainless steel has been investigated during the slow strain rate test (SSRT) in high temperature water. The test was done on center-notched thin plate specimens. An optical direct observation system, consists of single crystal sapphire windows, was employed for crack growth measurements. The specimens suffered large scale yieldings during the SSRT. Obtained crack growth rates were analyzed with six kinds of dynamic parameters; the extension rate, the net section nominal stress, the stress intensity factor, the J integral, the time differential of J, and the modified J integral (C* integral). The analytical results indicated that the J integral and the time differential of J (dJ/dt) well figure out every data obtained at different extension rates. Particularly in crack growth mechanism, the dJ/dt seemed to be the most useful parameter. The crack tip deformation rate controls the dynamic SCC growth rate in film rupture model, and the dJ/dt corresponds to the deformation rate. It is also suggested that the crack growth rate analysis by the dJ/dt during SSRT can be consistently understood corresponding to that by a frequency in cyclic loading.
