Dynamic strain aging in the high-temperature low-cycle fatigue of SA508 Cl. 3 forging steel

摘要: Abstract The effect of dynamic strain aging on cyclic stress response and fatigue resistance ASME SA508 Cl.3 forging steel for nuclear reactor pressure vessels has been evaluated in the temperature range room to 500°C. Total ranges rates were varied from 0.7 2.0% 4 × 10 −4 1 −2 s −1 , respectively. depended testing temperature, rate, range. Generally, initial hardening was immediately followed by softening at all rates. However, 300°C, operating vessels, variation amplitude showed primary secondary stages dependent rate Dynamic manifested enhanced hardening, distinguished negative sensitivity. A modified cell shutting model described onset due it good agreement with experimental results. Fatigue life increased temperatures. Specifically longer temperature. Further, easy initiate crack, while crack propagation retarded branching suppression plastic zone, hence caused improvement resistance.