The manufacturing process.

The cold drawing process consists of two stages: the plastic forming step and the production – on a continuous basis – of long steel wires or bars with circular sections or complex sections.

This forming process is achieved thanks to specific equipment and forming dies characterised by matrix with increasingly lower diameters. The semi-finished product undergoes various steps, or cold drawing “steps”. Each step consists in the traction in a different die and the progressive reduction of the section, until profile reaches the required size.

Sipa S.p.A. can rely on a highly consolidated manufacturing process: state-of-the-art cold drawing that guarantees dimensional accuracy and an excellent finish on the surface, because it is based on the careful selection of the processing parameters, the best design of the forming dies in terms of profile and angle, and the right choice in the section reduction at each step.
Sandblasting, bonderizing, straightening and cutting complete the standard manufacturing process. Each stage is monitored based on effective quality control procedures.

 

THE STAGES

Once the pre-shape is received, the raw materials and equipment are prepared.

Sand and air jets, together with soaking in a phosphate solution: these are the processes required to eliminate any traces of dust, oxide, oily and galvanic residue from the surface of the semi-finished product. This also ensures the surface is perfectly consistent with high anti-rusting properties.

The semi-finished product  is then cold drawn as it moves through the various “steps” required.

This operation makes it possible to definitively straighten the cold drawn profiles, thus optimising the straightness and flexure levels.

Despite developments over time providing potential alternative methods, cutting using a hacksaw, especially automatic, is still currently the most affordable and high-performing method for sectioning bars, and cutting them with a high degree of precision.

The cold drawn profiles undergo different tests to check on the dimensional and mechanical aspects, such as optic projector, static traction and hardness testing.

The cold drawn profiles, which are either in bars or coils, are delivered to our customers according to the required deadlines.

TECHNICAL AND PERFORMANCE SPECIFICATIONS

  • Batch sizes: 500 kg/1000 kg depending on the type of steel and shape
  • Closer tolerances: minimum tolerance 0.05 mm
  • Roughness values: Ra 1.6 minimum
  • Maximum diameter of a profile outside rim: Ø 151 mm
  • Bars’ maximum length: 7000 mm
  • Maximum weight per meter: 30 kg/m
  • Minimum radius: R 00:20