Based from steel billets 150x150 mm with 18 meters length, we produce our hot rolled wire rods with diameters from 5 to over 40 mm. Each diameter needs its special rolled sections, each material an adapted sequence for diameter reduction. Our experience allows intermediate dimensions as well as thermomechanical rolled wires.
Cold drawing or rolling is carried out in our drawing shops. This cold working results in plastic deformation and thus work hardening. Work hardening can be desirable, such as in voestalpine Special Wire, where final strengths are close to the theoretical strength of steel. In most cases, however, it forces us to go through several annealing, pickling and drawing steps to reach the final diameter.
Wire drawing requires drawing dies. These are usually round and have an opening in the center through which the wire is drawn and where the diameter decreases. The geometry (e.g. contact length, forming angle) depends on the steel type and strength, as does the selection of the appropriate drawing lubricant. Only the optimum combination results in the perfect wire.
The shaping of profiles is another area of expertise, which will be explained in another article.
Most of our customers do not use hard-drawn wire because they themselves have further forming steps in mind, for example to produce a hollow rivet. To make this possible, we supply our wires annealed and pickled and coated according to customer requirements.
The development of other coatings is a highly innovative step, because these coatings must either provide good sliding properties; withstand large forming steps, perhaps even temperatures up to 420°C. They may serve to protect against corrosion or simply provide brief protection against abrasion. Ideally, this coating should also be removable so that the customer has no limitation in his planned visual finish.