Low Cycle Fatigue and Ratcheting Behavior of SA333 Gr-6 Steel at 300°C Temperature

The objective of this investigation is to study the cyclic deformation behavior of SA333 Gr-6 C-Mn steel at 300°C. Low cycle fatigue tests were carried out at total strain amplitude between ±0.35 and ±1.25% at a constant strain rate of 1 × 10⁻³ s⁻¹. Ratcheting tests were conducted at a various combination of mean stress and stress amplitude at a constant stress rate of 115 MPa s⁻¹. The material SA333 Gr-6 steel exhibits cyclic hardening throughout its fatigue life. The material shows non-Masing behavior and deviation (δσ_o ) from Masing behavior increase with an increase in strain amplitude. Ratcheting strain accumulation increases, whereas ratcheting life decreases with an increase in mean stress or stress amplitude. With an increase in mean stress and stress amplitude, ratcheting rate also increases. The material shows hardening characteristic due to dynamic strain aging (DSA) phenomena.