Stefana SpA, a manufacturer of bars and wire rod located in Ospitaletto, a town in the northern Italian province of Brescia, had awarded a contract to SMS Meer Germany in 2005 for the supply and installation of a complete bar mill for 120 tonnes per hour. The objective of the project named “Dream Steel” was to significantly boost production of straight bars and spools.
With its annual capacity of 700,000 tonnes, this new plant is among the rolling mills with the highest productivity in southern Europe. The product mix of the bar mill includes rebars and plain rounds with diameters from 8mm to 16mm produced with the two slit rolling method and with diameters from 18mm to 40mm produced in a single line.
The SMS Meer scope of supply included a walking-hearth furnace, the rolling line, the finishing section and two VCC® Vertical Compact Coiling lines.
The walking hearth furnace is designed for heating 160mm x 160mm square billets with lengths of 16 meters. With its dimensions, this unit ranks among the world’s largest for reheating of starting material for long product rolling mills. A connection to the existing caster allows the billets to be charged either hot or cold. The furnace includes all the necessary equipment for charging and discharging.
The rolling mill comprises 16 housing less stands consisting of six roughing mill stands arranged in horizontal and vertical configuration, and ten intermediate/finishing stands arranged in horizontal, vertical and convertible configuration. The scope of supply also included two finishing blocks each with six passes, three cooling sections for rebar quenching and self-tempering from rolling heat, two cooling bed shears and the patented HSD® High-Speed Delivery system. The HSD® system with four rotating channels allows high-speed rolling using the two-slit method in order to permit very high production rates with the smallest bar sizes.
When planning the layout of the mill, space was allowed for the future installation of a billet welder for endless rolling operation and a possible expansion for the production of wire rod.
The finishing area consists of a 90 meter long cooling bed, transport facilities, a cold shear, bundling equipment, four automatic tying machines with automatic labeling device, bundle transport ways and all the necessary utilities. All products are delivered onto the cooling bed with a final speed of up to 40 meter per second using the patented HSD® system. The entire mill has been designed and equipped, however, to allow a speed increase up to 50 meters per second in the future.
On the two VCC® lines Vertical Compact Coiler lines, consisting of cooling boxes, shears, spooling equipment, a spool manipulator, two strapping machines, transport facilities and a weighing station, rebars with diameters from 8 to 16 mm are coiled into spools at a speed of 35 m/s. When charging 16-m-long square billets, the spools have weights up to 3.2 t with a diameter and a height of 700 mm.
SMS Meer acted as system integrator, supplying all the electrical and electronic equipment, controls and software for the mill automation. Furthermore, erection and supervision of commissioning of the mill as well as training of the customer’s personnel were also part of the scope of supplies and services.
