Residual stresses in metal components, particularly in deep-drawn sheet metal parts, can lead to dimensional instability, noise, and premature failure. In this study, we developed a cost-effective approach to residual stress relief by utilizing press-fitting strain—an inherent assembly process—to mitigate internal stresses without requiring additional processing. A nondestructive residual stress sensing method based on X-ray diffraction (XRD) with the sin²ψ technique was employed to monitor and evaluate stress variations at multiple locations on low-carbon steel components. The XRD system functions as a precision sensor for detecting internal stress distributions through changes in crystal lattice spacing, providing critical data on stress relief behavior. Experimental results revealed a location-dependent response: while stress increased at regions far from the press-fit zone, a significant reduction was observed directly beneath the press-fitted interface. This highlights the dual role of mechanical interference both as a joining method and an effective in-process stress relief strategy. The findings demonstrate a novel sensing-integrated framework for residual stress measurement in metal forming, supporting future developments in intelligent manufacturing and sensor-based process monitoring systems.