Cold Drawing

Cold drawing is the process of reducing the diameter and improving surface quality of hot rolled bars by passing them through a die at room temperature. As a result of this process, the product gains precise tolerance (h9, h10, or h11), bright surface, and enhanced mechanical properties. Production is carried out in accordance with EN 10277 and EN 10278 standards.

Before processing, hot rolled bars pass through the pickling (acid washing) line to remove scale and oxide layer from the surface. Then, a protective phosphor crystal layer is formed on the surface through phosphating, and friction between die and material is reduced by soaping. This surface preparation stage directly affects drawing quality.

During the drawing operation, the bar tip is pointed and passed through the die, then pulled through the die by applying force on the hydraulic drawing bench. A 10–35% cross-section reduction is applied in a single pass. When further reduction is required, multiple passes are made with intermediate annealing. Surface roughness of Ra ≤ 1.6 µm is achieved using tungsten carbide or synthetic diamond dies.

After cold drawing, bars pass through the straightening machine and are cut to desired tolerance. Each bar is measured with a laser micrometer; diameter, ovality, and straightness values are checked according to EN 10278 specifications. Products are ideal input material for free-cutting steels and CNC machining.