Cold-drawn wire is manufactured from hot-rolled wire rod as raw material. At ambient temperatures, the wire is forcibly drawn through tapered die holes, causing the steel's cross-section to shrink and its length to elongate. This process ultimately produces a filamentary steel product with specific diameter and mechanical properties. It constitutes a subcategory of cold-rolling processing, characterised by its core attributes of ‘cold-state forming’ and ‘controllable precision’.

I. Core Production Process: Progressive Shaping from ‘Wire Rod’ to ‘Fine Wire’

The production core lies in ‘forced deformation through drawing dies,’ requiring multiple stages to eliminate defects and control precision. The specific process is as follows:

Raw Material Pre-treatment:

The raw material consists of hot-rolled wire rods with diameters ranging from 5 to 15 millimetres. The surface scale must first be removed to prevent it from scratching the dies during drawing or embedding into the wire surface.

Following acid pickling, the wire undergoes either ‘phosphating treatment’ or ‘lubricant coating’ to reduce friction between the wire and dies during drawing, thereby protecting surface quality.

Multi-pass cold drawing:

The pre-treated wire rod enters the cold drawing machine, where it is forcibly drawn through a tapered hole in a carbide die. As the deformation achievable in a single pass is limited, multiple passes are required: for instance, an 8mm diameter rod is first drawn to 7mm, then to 6mm, until the target diameter is reached.

During drawing, plastic deformation induces ‘work hardening’ in the steel. Should intermediate hardness become excessive and impede subsequent drawing, an ‘annealing process’ is inserted before continuing.

Finished Product Processing:

Upon achieving the target diameter, subsequent processing is performed as required:

Direct coiling;

Cutting into fixed-length straight lengths;

Under special requirements, undergo ‘straightening’, “galvanising”, or ‘annealing softening’.

II. Key Characteristics: High Strength, Precise Dimensions, Controllable Surface Finish

Compared to hot-rolled wire rods or other wire products, cold-drawn wire's core advantages lie in its ‘performance and precision’, featuring four key attributes:

Superior Mechanical Properties: Work hardening during cold drawing significantly enhances wire strength and hardness, providing excellent tensile and bending resistance suitable for load-bearing applications.

High dimensional accuracy: Through precise die-hole control, diameter tolerances can be maintained within ±0.01–0.05mm. The wire exhibits excellent diameter uniformity with minimal thickness variation, meeting stringent dimensional requirements.

Controllable surface quality: Pre-treatment combined with die drawing removes scale and defects from the hot-rolled surface. The finished product exhibits either a ‘smooth, burr-free’ finish or ‘subtle drawn texture’, eliminating the need for additional polishing before use.

Flexible specifications: A remarkably broad diameter range from 0.01mm to 20mm can be produced to match diverse downstream requirements. Additionally, wire hardness and strength can be flexibly controlled by adjusting drawing passes and annealing processes.