Wire drawing processes typically consist of multiple passes, with each pass using dies of varying apertures to gradually reduce the wire diameter. Taking the processing of square steel as an example:
Pre-treatment: The raw material (e.g., 20mm diameter round steel) is pickled to remove the oxide layer, followed by phosphating to form a lubricating layer and reduce tensile friction.
Initial Drawing Pass: A larger aperture die (e.g., 18mm) is used at a lower drawing speed (e.g., 5m/min) to complete the initial deformation, preventing overheating.
Intermediate Passes: Smaller aperture dies are gradually used (e.g., 16mm, 14mm), with the drawing rate controlled at 10%-15% per pass to prevent cracking.
Final Drawing Pass: A high-precision die (e.g., 12.5mm) is used in the final pass, combined with fully automated control (e.g., the fully automated control specified in the product parameters), to control the diameter error within ±0.01mm.
Post-treatment: The finished wire is wound into a coil using a take-up device. In some cases, annealing is required to eliminate internal stress.