<p>Silicon steel is characterized by a high melting point, poor fluidity, and limited wettability, and the process window for the preparation of non-oriented silicon steel ribbons by planar flow casting (PFC) is limited. During the production process, the melt puddle (MP) behavior is a key factor in determining the final quality of ribbons, and the influence mechanism of the airflow boundary layer on the MP behavior and the surface quality of ribbons is still unclear. The effects of wheel speed on the quality of PFC Fe–3.0%Si non-oriented silicon steel ultra-thin ribbons were systematically investigated. Combined with experiments and numerical simulations, the mechanism of different wheel speeds on the behavior of MP and the surface quality of ribbons was analyzed in depth. It is found that when the MP reaches a steady state, the upstream meniscus shows a C-shape, while the downstream meniscus exhibits a sloped shape. During the formation of the MP, the vortex phenomena occur both around and within the MP. With the increase in wheel speed, the thickness of the ribbons gradually decreases from 67 to 31&#xa0;μm. Furthermore, the air vortex on the upstream and downstream meniscus becomes more and more intense, which significantly increases the possibility of air entrapment in the MP and leads to a significant increase in the percentage of air pockets. When the wheel speed is 10–15&#xa0;m/s, the surface of the ribbon is smooth, the thickness uniformity is better, and there are fewer defects. However, when the wheel speed is more than 15&#xa0;m/s, the MP’s stability deteriorates, and the ribbons have obvious veining, wrinkles, and uneven thickness.</p>