Effects of High-Frequency Vibration on Residual Stress and Microstructure of Carbon Steel for Marine Structures: Comparative Analysis with Tempering

To improve the safety and service life of carbon steel used in marine structures, appropriate regulation of residual stress in carbon steel is required. This paper investigates the effects of high-frequency vibratory stress relief (VSR) and tempering on the residual stress, microstructure, and surface hardness of 45 steel. After the high-frequency VSR and tempering at 200 °C for 30 min treatment, the microstructure is still tempered martensite. When the 45 steel experimental specimens were tempered at 600 °C for 30 min, the microstructure changed from tempered martensite to tempered sorbite, and the residual stress regulation effect of 45 steel experimental specimens was significantly improved. However, its surface hardness decreased significantly, which reduces the mechanical properties of marine structural components. Comparatively, high-frequency VSR is an effective method to regulate residual stress while ensuring that the microstructure of marine structural components does not undergo drastic changes. This study provides technical and theoretical support for the residual stress regulation treatment of 45 steel in marine engineering.