Environmental Fatigue Testing of Type 316 Stainless Steel in 310 °C Water

Abstract

Low cycle fatigue tests were conducted to investigate fatigue behaviors of Type 316 stainless steel in 310 °C low oxygen water. In the tests, strain rates were 4 × 10−4, 8 × 10−5 s−1 and applied strain amplitudes were 0.4, 0.6, 0.8, and 1.0%. The test environment was pure water at a temperature of 310 °C, pressure of 15 MPa, and dissolved oxygen concentration of < 1 ppb. Type 316 stainless steel underwent a primary hardening, followed by a moderate softening for both strain rates in 310 °C low oxygen water. The primary hardening was much less pronounced and secondary hardening was observed at lower strain amplitude. On the other hand, the cyclic stress response in room temperature air exhibited gradual softening and did not show any hardening. The fatigue life of the studied steel in 310 °C low oxygen water was shorter than that of the statistical model in air. The reduction of fatigue life was enhanced with decreasing strain rate from 4 × 10−4 to 8 × 10−5 s−1.

Fatigue Life and Crack Growth Mechanisms of the Type 316LN Austenitic Stainless Steel in 310°C Deoxygenated Water

“…The reduction in the fatigue life of the metals in high-temperature water may be induced by the occurrence of the typical EAC mechanisms, such as the metal dissolution and the HIC. 3,5,10) As mentioned previously, for austenitic SSs, the appearance of the metal dissolution is still in controversy and the evidences of HIC occurred in high-temperature water are insufficient. So, in the current study, the microstructure observation was performed to investigate the fatigue cracking mechanisms of the type 316LN SS in high-temperature water.…”

“…As reactor components are subjected to the cyclic stresses in high-temperature corrosive aqueous environments, the environmental fatigue damage of metallic components is one of the most important degradation mechanisms in nuclear power plants. [1][2][3][4][5] As austenitic Stainless Steels (SSs) have been used widely as structural materials in nuclear power plants, the Low Cycle Fatigue (LCF) behaviors of austenitic SSs in high-temperature water are important to assess the integrity of nuclear power plant components. Thus far, many studies regarding the environmental fatigue of austenitic SSs have been performed in high-temperature water, 1,5) and several models have been suggested to incorporate the environmental effects on the fatigue life evaluation process.…”

“…[1][2][3][4][5] As austenitic Stainless Steels (SSs) have been used widely as structural materials in nuclear power plants, the Low Cycle Fatigue (LCF) behaviors of austenitic SSs in high-temperature water are important to assess the integrity of nuclear power plant components. Thus far, many studies regarding the environmental fatigue of austenitic SSs have been performed in high-temperature water, 1,5) and several models have been suggested to incorporate the environmental effects on the fatigue life evaluation process. [1][2][3][4] The Argonne National Laboratory (ANL) has produced considerable amounts of the fatigue life data of austenitic SSs in Light Water Reactor (LWR) environments.…”

Environmental Fatigue Behavior of a Z3CN20.09M Stainless Steel in High Temperature Water

“…Corrosion and environmental fatigue damage is one common material degradation process in nuclear power plants [1][2][3][4][5][6]. The wide use of austenitic stainless steels (ASSs) to fabricate nuclear power plant components raises the importance to investigate their low-cycle fatigue (LCF) properties in a light water reactor (LWR) environment to ensure the integrity and safety of nuclear power plants [3,4,6,7]. Furthermore, the ASME design fatigue curve cannot explicitly address the contribution of the service environment to the service life of these ASS components [3,5,8].…”

“…Furthermore, the ASME design fatigue curve cannot explicitly address the contribution of the service environment to the service life of these ASS components [3,5,8]. Recently, many studies related to corrosion fatigue of SSs have been performed and tried to address the effect of the corrosive environment at high temperatures (i.e., 300 • C) on their fatigue life and possible fatigue mechanism [2,5,6,9]. A large number of research data on corrosion fatigue of ASSs in simulating the environment in LWR were collected by Keisler et al [2] in the Argonne National Laboratory (ANL).…”