Siemens Completes Slab Caster Modernization for Acroni
08/03/2009 - Siemens VAI Metals Technologies completes a comprehensive modernization of an over 20-year-old, single-strand slab caster at the steel works of the Slovenian producer Acroni, d.o.o.
Siemens VAI Metals Technologies recently completed a comprehensive modernization of an over 20-year-old, single-strand slab caster at the steel works of the Slovenian producer Acroni, d.o.o.
Siemens replaced the caster’s machine head and strand-guiding system and outfitted it with the latest technological packages, systems and equipment to enable Acroni to cast wider slabs with significantly improved quality. Equipped with a curved mold and a 10.36-meter casting radius, the refurbished slab caster is now capable of casting approximately 515,000 tonnes of steel per year comprising medium- to high-carbon, peritectic, structural, micro-alloyed, stainless steel (series 300 and 400) and Si grades. Slabs can be cast at thicknesses of 200 and 250 millimeters and in hot widths from 800 to 2120 millimeters, a significant expansion from the previous maximum casting width of 1560 mm.
Siemens replaced the caster’s machine head and strand-guiding system and outfitted it with the latest technological packages, systems and equipment to enable Acroni to cast wider slabs with significantly improved quality. Equipped with a curved mold and a 10.36-meter casting radius, the refurbished slab caster is now capable of casting approximately 515,000 tonnes of steel per year comprising medium- to high-carbon, peritectic, structural, micro-alloyed, stainless steel (series 300 and 400) and Si grades. Slabs can be cast at thicknesses of 200 and 250 millimeters and in hot widths from 800 to 2120 millimeters, a significant expansion from the previous maximum casting width of 1560 mm.
The upgraded caster now features a Siemens VAI Smart Mold and DynaWidth technology that allows the mold narrow sides to be hydraulically shifted for the flexible casting of strands of different widths. The use of so-called Smart Segments installed in the caster’s bow, straightening and horizontal zones allow the roller-gap settings to be remotely adjusted for fast slab-thickness changes. I-Star Rollers (intermediately supported trans-axle rollers) installed throughout the strand-guiding system help to provide the ideal strand-shell support necessary for high slab quality.
Other technological packages installed in the Acroni caster include LevCon, which helps to provide automatic and precise mold-level-control; MoldExpert for enhanced strand-break-out protection; and DynaFlex for the on-line adjustment of the mold-oscillation parameters. A fully automatic and dynamic Level 2 Dynacs secondary-cooling model facilitates calculation of the stand-temperature profile and the required secondary cooling-water quantities at any position along the strand as the basis for defining the optimum secondary-cooling setpoints and final point of strand solidification. DynaGap Soft Reduction technology helps to provide improved internal strand homogeneity and high slab quality. This is achieved through the exact adjustment of the roller taper in the area of final strand solidification according to the Dynacs-calculated setpoints.
Other technological packages installed in the Acroni caster include LevCon, which helps to provide automatic and precise mold-level-control; MoldExpert for enhanced strand-break-out protection; and DynaFlex for the on-line adjustment of the mold-oscillation parameters. A fully automatic and dynamic Level 2 Dynacs secondary-cooling model facilitates calculation of the stand-temperature profile and the required secondary cooling-water quantities at any position along the strand as the basis for defining the optimum secondary-cooling setpoints and final point of strand solidification. DynaGap Soft Reduction technology helps to provide improved internal strand homogeneity and high slab quality. This is achieved through the exact adjustment of the roller taper in the area of final strand solidification according to the Dynacs-calculated setpoints.
“Through the modernization of our continuous slab-casting machine we have acquired one of the most advanced machines of its kind in the world, which increases our production potential,” said Emil Subelj, Acroni Project Manager and Deputy Steel Plant Manager. “This new acquisition enables us to cast wider slabs and increase our productivity in casting new types of steel using modern control and cooling systems.”
Siemens VAI’s scope for the caster upgrade comprised design, manufacture, delivery, supervision of installation, start-up and commissioning of the caster as well as personnel training. The project scope also involved civil and erection work, integration of new and existing equipment, the supply and installation of electrics, technological packages, Level 1 and Level 2 automation systems in addition to the media, hydraulic and lubrication systems. The existing top-feeding dummy-bar system with a chain-type dummy bar was modified for reuse. The caster workshop area was improved with new maintenance stands. Greater personnel safety is assured with the installation of safety guards which prevents operators from entering the cooling chamber during casting.
All onsite construction activities were completed in the spring of 2009 within a tight timeframe of only 38 days. Plant start-up proceeded smoothly and all casting equipment and systems functioned as designed beginning with the first heat. Following fulfillment of the guaranteed performance figures for various steel grades, the Final Acceptance Certificate was received within 2 months after the plant start-up.
The Slovenian steel producer Acroni d.o.o. is located in Jesenice, about 60 km northwest of the capital of Ljubljana. In 2008 the company produced a total of 375,700 tonnes of flat-rolled stainless, electrical, structural and special steels which were sold as hot- and cold-rolled coils, heavy plates and cold-formed profiles, primarily for special niche products.
The Siemens Industry Sector (Erlangen, Germany) is a leading international supplier of production, transportation, building and lighting technologies. The Sector comprises six Divisions: Building Technologies, Drive Technologies, Industry Automation, Industry Solutions, Mobility and Osram. With around 222,000 employees worldwide Siemens Industry posted in fiscal year 2008 a profit of EUR3.86 billion with revenues totaling EUR38 billion
With the business activities of Siemens VAI Metal Technologies (Linz, Austria), Siemens Water Technologies (Warrendale, Pa.), and Industrial Technologies (Erlangen, Germany), the Siemens Industry Solutions Division (Erlangen, Germany) is one of the world's leading solution and service providers for industrial and infrastructure facilities. Using its own products, systems and process technologies, Industry Solutions develops and builds plants for end customers, commissions them and provides support during their entire life cycle. With around 31,000 employees worldwide Siemens Industry Solutions achieved an order intake of EUR 8.415 billon in fiscal year 2008.
