The creed crack growth behavior of the SUS 304 stainless steel was investigated at 650°C using tension-type (CN and DEN) and bending-type (SEN and CT) specimens, in order to discriminate the most probable governing mechanical parameter of the phenomenon from several candidate mechanical parameters. The following mechanical parameters were examined in this study; stress intensity factor
KI, elastic net section stress (σ
n)
e, rigid-plastic net section stress (σ
n)
p and modified J-integral
J' (C* parameter). The effect of temperature on the creep crack growth behavior of center-notched (CN) specimens was also investigated.
It was found that the creep crack growth rates could successfully be correlated with
J', regardless of the types of specimens selected in this study, while the other three mechanical parameters,
KI, (σ
n)
e and (σ
n)
p, gave poor correlations with the crack growth rates. This result was quite consistent with those in previous studies obtained by using several series of proportional specimens with different tension-type geometries (CN, DEN and round bar). It was concluded that
J' is the most probable mechanical parameter which governs the creep crack growth behavior. Temperature increased the creep crack growth rates and the correlation curves of the crack growth rates with
KI and (σ
n)
e[≡(σ
n)
p, in this case]moved upwards and approximately in parallel. However, the correlation curves with
J' were almost unaffected by temperature. This may be a very convenient and useful property in various engineering applications.
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