Ultrasonic welding has become a key joining approach in batteries and energy vehicles. This work reports the optimization in static property and stability of self-piercing riveting joints which is becoming the most versatile way to join microstructures. Tool heads of three different knurling profiles (e.g., A, B, and C) are used to perform ultrasonic composite with riveting. Based on tensile-shear tests, SEM, EDS, XRD, and Vickers microhardness analysis were conducted to investigate the comparative study of the fracture morphology, element distribution, phase structure, and hardness. The results indicated that all three types of knurling generate solid phase welding at the sheet joints. Thus, it improved the forming quality and mechanical properties of self-piercing riveting joints. The C-shaped welding tool head has advantageous effect on optimizing the mechanical properties of joints. Further, it enhanced the average peak load by 25.6%, the average failure displacement by 31.1%, and the average energy absorption by 88.8%. The microscopic results showed that a large amount of oxides are precipitated at the edge of welding joints when the B-shape knurling tool is used. The distribution of the hardness value of joints horizontal line is “M” shape. Besides, the coarse grains in the joint area and the interplanar space increase significantly after ultrasonic welding which softens the sheet. © 2023, The Author(s), under exclusive licence to Springer-Verlag London Ltd., part of Springer Nature.