THE COLD-DRAWN PRODUCT
To understand the merits of a cold-drawn product we must first describe how the metal alloy that composes it is born. There are two main production processes through which steel is produced.
Steel-making process via blast furnace: this is a particular type of furnace covered with refractory bricks and is reinforced by a metal structure, in which the iron ore is reduced to cast iron for conversion into steel through appropriate treatments.
Steel-making process via electric furnace: a refractory furnace in which the materials to be melted are placed. The transmission of thermal energy through three electrodes begins the scrap charge melting process.
The material obtained by means of these two manufacturing techniques mainly ends up in the rolling mill, from which the rolled product originates. The rolled product is obtained by hot deformation of blooms, billets, etc. (+RA raw rolling natural state).
The semi-finished product is not always suitable to fulfil the multiple demands of the market because of the surface appearance of the raw material, or for dimensional tolerances not corresponding to use, due to lack of sharp edges or non-conforming straightness, etc.
Therefore, in most cases it must be subjected to roughing, milling, turning, grinding or drawing operations that make it conform to the requirements of the designer and the user's expectations.
With these steps, the laminate loses on average 20% of its initial weight. The additional hours of machining required to shape the finished product have the greatest impact on costs.
The cold-drawn product (+C) gives, where possible, a precise answer to the needs highlighted above. This product obtained from raw laminate takes on aspects and intrinsic qualities that only cold transformation with a detailed drawing technique can express. The drawn material is a product without scales, which is very important in mechanical processing because the iron oxide pollutes the lubricants and inevitably gives rise to mechanical failures. It is glossy, very straight and with tolerances even below 1 mm/m. The dimensions are constant along the entire length for thousands of metres (which is absolutely impossible to achieve using other technologies), the dimensional deviations are very tight, at the level of hundredths, the edges can be live or calibrated according to specific requests, and in most cases the drawn product is suitable for supply. To understand the importance of this steel product, we can take into account the precision of any hexagonal, square, flat or round geometric section, or the formation of more complex sections such as sliding guides for optical readers, splined shafts, transmissions for textile machines and many other special sections where the precision of several hundredths must absolutely be kept under control. The advantages of drawn sheets make it possible to obtain a greater purchase cost with a reduction in processing cycles compared to laminate, as well as significantly lower material waste.