Cold heading makes it possible to obtain mechanical parts from the wire rod using plastic deformation on multi station presses making it possible to produce screws, bolts, nuts, spacers, pivots, rivets, fasteners and other special components according to design. A group of steels with structural morphology and reduced hardening factors, designed and produced to guarantee increased deformability so as to reduce forming and cutting machine tool wear to a minimum.
|Valbruna Grade||Steel type||W.N.||AISI||UNS||EN||BS|
|AISR/1||Austenitic Stainless Steel||1.4301/1.4307||304/304L||S30400/S30403||X5CRNI18-10/X2CRNI18-9||304S15/304S31|
|APMR||Cold Heading||1.4401 / 1.4404||316 / 316L||S31600 / S31603||X2CrNiMo17-12-2 / X5CrNiMo17-12-2||316S14 / 316S19|
|AN5||Corrosion Resistant Alloys||1.4980||-||S66286||-||-|
This process involves drawing the material through a precision die which defines the bar into precise dimensional and geometrical tolerances. Cold Draw tolerances are much more precise than that of hot rolled materials. Additionally, the post drawn surface is much smoother.
Cold drawing generates work hardening which increases strength by changing the structural morphology in a more or less marked manner, depending on the type of steel, the steels work-hardening rate and the percentage change of the cross sectional area of the material by the cold drawing process. The cold drawing operation can be carried out by coil to bar, coil-to-coil or from bar-to-bar. In general, except for few exceptions, all stainless steels can be drawn to some extent. Factors for successful drawing include the right choice of die angles, proper lubrication and the condition of the material. Particular care must be exercised when drawing re-sulfurized steels and those with a high transition temperature.