To address challenges in repairing power plant piping, we investigated the fatigue life characteristics of bonded structures made of SUS316L/SUS304 which was fabricated using Laser Metal Deposition (LMD) technology. We conducted fatigue tests using miniature specimens at room temperature and performed SEM observations to investigate the microstructural characteristics and its fracture mechanisms. The results showed that no cracking occurred at the bonding interface by the fatigue tests. Under high-stress conditions, specimens cut from the LMD layer exhibited a longer fatigue life. Under low-stress conditions, bonded specimens demonstrated a longer fatigue life, with fracture typically occurring on the LMD side. SEM observations revealed smooth dimples and surface cracks in the LMD material. These results indicate that cracks generated during the LMD additive manufacturing process significantly impact the fatigue life of materials, with a greater influence under high stress levels due to stress concentration effects. However, the impact diminishes under low stress conditions.
Zhang et al. (Wed,) studied this question.