The main methods for preparing copper rods are the upward drawing method and the continuous casting and rolling method, used for producing oxygen-free copper rods and low-oxygen copper rods, respectively.
The upward drawing method is primarily used for producing oxygen-free copper rods. Its basic process flow is: electrolytic copper → melting furnace → holding furnace → continuous casting machine (upward crystallization) → take-up. This method was first developed and researched domestically by the Shanghai Cable Research Institute of the Ministry of Machinery Industry. It features a short process flow, high yield, low investment, flexible production, and no waste pollution. Key process control parameters include furnace temperature (e.g., 1150±5℃), cooling water temperature (25-35℃), pressure (0.2-0.3MPa), and drawing speed (1.2-1.9 m/min), which directly affect the purity, oxygen content, and performance of the copper rod.
The continuous casting and rolling method is primarily used for producing low-oxygen copper rods. Its basic process flow is: electrolytic copper → feeding machine → vertical furnace → holding furnace → casting machine → continuous rolling mill → cleaning → take-up. This method boasts high production efficiency, large output, and low cost, but its oxygen content is relatively high. In the continuous casting and rolling process, unstable processes and inadequate oxygen monitoring will directly impact the rod's performance.
Furthermore, dip coating can also be used to produce oxygen-free copper rods. The traditional hot rolling method (for producing black rods) has been replaced by continuous casting and rolling. Major production equipment includes the US Southern Line (SCR), German Contirod continuous casting and rolling production lines, and domestically produced upward-drawing continuous casting units. Production lines using continuous casting and rolling to produce oxygen-free copper rods exist.