When machining the φ2.3×3.89m slag rotary furnace shell at the Heavy Complete Equipment Factory, the traditional horizontal lathe processing method was replaced with vertical lathe machining. This approach not only saves time on tooling and clamping, but also enables parallel operations without waiting for workpieces to be unloaded from the horizontal lathe, effectively improving equipment utilization. The same process will be adopted for the subsequent φ2.62×3.95m silver separation furnace shell. Continuous progress is achieved in cost reduction and efficiency improvement.