Answer
Coiling a spiral retaining ring involves significant plastic deformation, which introduces high residual tensile and compressive stresses throughout the cross-section. Without stress relieving, these residual stresses can lead to 'spring-back' or 'creep' (dimensional instability) over time. For SAE 1070 carbon steel, stress relieving is typically performed at $250^{\circ}C$ to $350^{\circ}C$ for $30$ to $60$ minutes. This temperature is below the tempering temperature, so it does not reduce the hardness of the martensitic structure but allows for the rearrangement of dislocations to a lower energy state. For stainless steels like 302, the temperature is higher, around $400^{\circ}C$ to $450^{\circ}C$, to ensure dimensional stability in the coiled state.
