Acciaieria Arvedi

Arvedi ISP/ESP technology the most advanced of the modern compact technologies The process technology, now called as a whole “Arvedi ISP/ESP”, is based on the casting of a thin steel strand rolled in-line and continuously into the coiled product; developed at the end of the 1980s on the ideas of the Chairman, Giovanni Arvedi, it is covered by 460 patents covering the most important industrialised countries regarding both the technology as a whole and the single plant component parts. The idea, which became reality in 1992 in the Cremona works, was to produce large quantities of hot rolled thin gauge products through a process line which transforms the steel produced in an EAF or converter in a continuous and single, extremely compact cycle into quality steel coils that conventional plants and other thin slab technologies were unable to produce or produced at non-competitive costs. With the ISP (In-line Strip Production) line the transformation of the liquid steel into quality coils through casting and continuous in-line rolling is achieved directly in the first rolling phase in only 180 metres and about 15 minutes, exploiting the energy contained in the liquid steel and its high plasticity at high temperatures. The pre-rolled strip is heated in the Induction Heater, accumulated in the Cremona Box and subsequently rolled to the final thickness. Thanks to this innovation, conceived and realised for the first time in the world within the Arvedi Group, the product has excellent qualities, energy consumption is very low and large quantities of ultrathin hot rolled steel in all steel grades can be produced. Fifteen years after stable start-up of the initial technology, after intense phases of study and applied research conducted within Acciaieria Arvedi, a new technology was developed called ESP (Endless Strip Production) which represents important and definitive technological progress. This great leap forward in development has been made concrete with the start-up in 2009 of the new ESP line which, through a totally in-line and continuous process, enhances and takes to completion the strong points already highlighted by the earlier technology from which it derives, the first of which is the high temperature endless rolling which exploits the energy content of the liquid steel in an evenmore complete way. In brief, over a length similar to ISP (only 180 metres) and in 4 minutes the new ESP process transforms the liquid steel into coils with gauges down to 0.8 mm through a rolling line composed of 3 roughing stands and 5 finishing stands. Installed power is much lower than conventional plants since rolling is carried out at high temperatures, and stresses and energy consumption are consequently lower. Compared with the ISP line productivity is more than doubled, thanks to the higher casting speed the Cremona Box is no longer present (in this way the process is fully continuous), and the induction heater is dimensioned with reduced criteria and power. The ESP technology, because it is completely continuous, reduces energy consumption to theminimumtechnically achievable, has higher performances (more homogeneous quality and particularly close dimensional tolerances), easier management of production of even thinner gauges with further cost reduction and even lower impact on the environment. A Consteel electric furnace (tapping capacity 250 tonnes) supplies the ESP line with liquid steel with the most precise analysis and purity characteristics. An innovation of epochal value: the direct connection of cast- ing and rolling. The thin strand leaving the mould is reduced in thickness while the core is still liquid and directly rolled at a high temperature to obtain a high precision intermediate strip with a homogeneous structure. The liquid steel is cast into thin strands through the mould system (patented by Arvedi) to obtain the best quality characteristics with a high degree of reliability. The intermediate strip, is re-heated in the Induction Heater, the first example of its kind in the world, and subsequently reduced to the final thickness by the finishing mill which operates at constant speed and temperature to obtain the best product characteristics. The continuously rolled strip, cooled with the most suit- able means to give the steel the desired mechanical and structural characteristics, is cut and subsequently wound on the downcoiler. The products cover the broadest range of steels and gauges down to hot rolled ultrathin gauges (0.8 mm) which for many applications can replace cold rolled strip. Cast-rolling Strip pre-rolled to 12.5 mm Induction heater Finishing mill Steel coil Flying shear and downcoilers Liquid steel The world’s only technology for continuous casting and rolling European patents nos 0415987 and 1868748 and others ESP