Effect of Casting Speed on Solidification Behavior and Porosity Defects in Low-Oxygen Copper Casting Rods Using SCR Technology

The Southwire Continuous Rod (SCR) process is widely used for producing low-oxygen copper rods, yet pore defects remain a significant challenge, affecting the performance and drawability of copper wire. In this study, the influence of casting speed on solidification behavior and porosity formation in low-oxygen copper casting rods was investigated by combining numerical simulation and plant trials. The simulation results indicate that increasing the casting speed elevates the flow velocity and impact depth of molten copper in the casting wheel. Simultaneously, higher casting speeds could raise the temperature of the casting rod and extend the liquid phase region, which suppresses the precipitation of dissolved gases from the melt. However, when the casting speed exceeds 26 t/h, the center temperature of the casting rod at the outlet remains close to the melting point of copper, retaining 10–20% liquid fraction. This predisposes the rod to remelting and the formation of remelt holes, and thus it fails to meet the design requirement for complete solidification of the SCR technology. Further industrial trials confirm that a casting speed of 23 t/h is optimal under current process conditions, yielding the lowest size and number of porosity defects in the casting rod.