The production of copper hollow conductors typically involves a series of processes, including semi-continuous ingot casting, water-sealed extrusion, drawing, annealing, and the application of insulation. For stainless steel hollow conductors, the process entails ingot casting, extrusion, solution treatment, drawing, and a subsequent solution treatment.
To manufacture the ultra-long, seamless rotor hollow conductors required for 700 MW dual-water internal-cooling generators-where the maximum weight per individual conductor reaches 273 kg-the project faced challenges exceeding the capacity limits of existing equipment (such as 2000-ton extrusion presses). Furthermore, the requirements for wall-thickness precision (±0.10 mm) were exceptionally stringent. The project team addressed these issues by innovating and optimizing die designs and tooling structures, monitoring dimensional changes throughout the manufacturing process, and systematically refining and standardizing core processes like extrusion and cold rolling to enhance dimensional consistency.
Additionally, to improve product precision and performance, the industry has adopted advanced processing equipment-such as the 200/150HC five-stand tandem precision rolling mill from the French company REDEX-ensuring minimal dimensional deviation, consistent electrical resistivity, and superior mechanical properties.
