The manufacturing process of steel-cored aluminum stranded wire mainly includes key steps such as raw material preparation, steel core treatment, aluminum wire stranding, and subsequent processing. Precise coordination ensures that the conductor possesses both high strength and excellent conductivity.
Raw Material Preparation and Inspection
Steel Core Material: Typically, high-carbon steel wire rod is drawn into steel wire and then galvanized or aluminum-clad to improve corrosion resistance and mechanical strength. Some high-end products use aluminum-clad steel wire (such as LB20 and LB35 grades), with a core strength exceeding 1800 MPa.
Aluminum Wire Material: High-purity (≥99.7%) electrolytic aluminum is selected and manufactured into hard aluminum wire through continuous casting and rolling processes. The conductivity is generally not less than 61% IACS.
Steel Core Pretreatment
Steel Wire Drawing: The steel wire rod is reduced to the target size through a multi-pass cold drawing process, controlling the dimensional tolerance within ±0.02 mm.
Surface Treatment:
Zinc Plating: Hot-dip galvanizing is used to form a uniform zinc layer (approximately 20–30 μm thick) on the steel wire surface, preventing electrochemical corrosion.
Aluminum-Clad Steel: An aluminum layer is densely coated onto the steel wire using the "Conform" continuous extrusion method, achieving metallurgical bonding and significantly improving corrosion resistance.
Conductor Stranding (Core Process)
Equipment: Completed on a frame stranding machine or fork stranding machine, supporting multi-layer concentric stranding.
Process Highlights: Using the treated steel core as the core wire, strand aluminum single wires layer by layer;
Adjacent layers are stranded in opposite directions (the outermost layer is right-hand/Z-direction) to prevent loose strands and reduce AC impedance;
Control the pitch ratio (outer layer not greater than inner layer) to ensure structural stability;
Untwisting stranding can be used to avoid single-wire self-twisting and improve yield.
