種々な水素発生電位下におけるSUS430ステンレス鋼のクリープ挙動

抄録

This study was intended to elucidate the behavior of minute creep strain in ferritic stainless steel SUS430 specimens which were subjected to various states of hydrogen evolution environment. Creep tests were carried out under various hydrogen evolution potentials and the results were compared and examined.
The results obtained are summarized as follows.
(1) From the comparison of creep curves obtained under various setting potentials with those in atmosphere, the creep strain was found to become smaller with lowering setting potential and the increase of hardness in the surface vicinity layer was observed. The creep curves obtained under different setting potentials were aligned in the order of atmosphere, -1.0V, -1.5V and -2.0V(vs. S.C.E.).
(2) The anomalous phenomenon in which minute creep strain increases with a wave motion appeared after testing for 10⁴sec. in all setting potentials. When the applied load exceeded 160kgf of the yield point, this anomaly appeared in large numbers and the value of wave motion became 0.4% or more in the minute creep strain. The minute creep strain increased by repeating this behavior. Therefore, even if the applied load is a yield point load at which the specimens don't fracture immediately, it may lead to fracture in a short period.