Abstract: As a critical heat transfer component in water cooling systems, the welding quality of Oxygen-free copper cannula directly impacts system reliability and cooling efficiency. This study examines induction brazing’s effects on brazing rate, interfacial microstructure, and mechanical properties of small oxygen-free copper casings. Results indicate that at 720°C peak temperature with 5s, 15s, and 30s holding times, brazing rates are good, but minor porosity appears at 15s and significant solder overflow at 30s. At 660°C, the weld bottom exhibits poor brazing rates and C-arc porosity but no overflow. Conversely, at 790°C with 5s holding time, brazing rates remain high, but severe C-arc porosity and solder diffusion occur. Overall, moderately increasing the peak temperature can reduce the pore size and enhance the brazing rate. However, overheating can lead to overflow, and an excessively long holding time can result in C-arc porosity and overflow defects. The optimal parameters are 720°C peak temperature with 5s holding time. The welding process will not have an impact on the overall mechanical properties of the casing structural components.