Evaluation of Static and Fatigue Strength of Bolts Manufactured By Selective Laser Melting and Wire Electrical Discharge Machining Under Various Torque Conditions

SLM Manufacturing and Testing Methods: The graphical abstract illustrates the Selective Laser Melting (SLM) process for fabricating hexagonal bolts, followed by mechanical testing methods, including tensile, fatigue, and creep tests, to evaluate their performance under various loading conditions. Key Findings and Applications: The results highlight enhanced fatigue life (135,000 cycles), creep resistance, and high tensile strength (UTS: 1189.32MPa, YS: 967.61 MPa), demonstrating the suitability of SLM-manufactured bolts for critical aerospace and automotive applications. Highlights The tensile testing of M5, M6, and M8 hexagonal bolts revealed high strength, with a UTS of 1189.32 MPa and YS of 967.61 MPa. Fatigue life improved significantly with torque tightening, increasing from 21,000, 25,000 cycles (pre-load) to 135,000 cycles under 12 N-mm torque. Creep testing confirmed excellent material stability under a sustained load of 660 MPa over 24 hours without deformation or failure. Torque tightening proved critical in extending fatigue life and preventing failure at critical stress points, such as the shankthread interface. The study demonstrates the effectiveness of Selective Laser Melting (SLM) in manufacturing hexagonal bolts, with the additive manufacturing (AM) process enabling the production of high-performance materials suitable for demanding structural applications. The results validate the use of SLM-based additive manufacturing for producing bolts with enhanced mechanical properties, offering significant potential in automotive and aerospace industries.