Siemens VAI Metals Technologies GmbH & Co received a contract from the Austrian steel producer voestalpine Stahl GmbH, a company of the listed voestalpine Group, for the supply of a new single-strand slab caster.
The order value for Siemens VAI is a two-digit-million euro figure. This will be the second slab-caster project to be implemented for the Linz-based steel producer capable of casting slabs in thicknesses of up to 355 millimeters: The upgraded machine was restarted in summer 2007. The new slab caster with a straight mold and a bow radius of ten meters is scheduled for start-up in September 2010. For the first time in a European steel works LiquiRob robot systems will be used on the casting platform. This will improve the safety of the operating personnel considerably.
Approximately 5.5 million tons of crude steel are currently produced in the LD 3 steel plant of voestalpine Stahl GmbH per year which are cast and processed to high-quality coated and non-coated flat-steel products. These are sold as sheets, coils and plates for use primarily in the European automotive, household-appliance and building-supply industries. As part of an ongoing modernization and steel-capacity-expansion campaign underway at voestalpine Stahl to increase the annual steel output to approximately six million tons, Siemens VAI was awarded a project for the installation of a new slab caster.
The slab caster will be capable of casting a nominal 1.4 million tons of slabs per year. The slabs will be produced in thicknesses of 225, 285 and 355 millimeters and in widths from 740–2,200 millimeters. The casting-bow radius will be ten meters and the metallurgical length approximately 35 meters. Roughly seventy percent of the cast slabs will be rolled to plates. Siemens VAI will supply the complete engineering and the equipment on a process turn-key basis, including assembly engineering and supervision, Level 1 automation and Level 2 process optimization.
The caster will be equipped with a wide range of the latest features and technological packages to enable the company to meet the highest product-quality demands in casting today, as well as to enable a flexible response to changing market requirements. This includes LevCon for improved automatic mold-level-control, MoldExpert for enhanced strand-break-out protection, SmartMold cassette-type molds which allow worn copper plates to be quickly replaced, and DynaWidth for the dynamic and on-line adjustment of the mold width. Flexible and on-line adjustment of the mold-oscillation parameters will be achieved with DynaFlex. Furthermore, the remotely adjustable SmartBender and subsequent SmartSegment caster segments will be supplied, which, in combination with DynaGap automation, will enable the slab thickness to be quickly and fully automatically adjusted. ECO-Star Rollers, represented the latest development in Siemens VAI roller design for optimum strand support, will also be supplied.
The well proven Level 2 Dynacs secondary-cooling model, capable of calculating the stand-temperature profile at any position along the strand, will define the optimum secondary-cooling setpoints and the point of final strand solidification, depending on the casting speed and the steel grade. An improved internal strand homogeneity for the production of highest quality plates will be possible through the application of DynaGap SoftReduction technology which adjusts the roller taper in the area of final strand solidification in accordance with the Dynacs-calculated setpoints. The new 3-D Spray system will allow slabs cast at different widths to be uniformly and ideally cooled. With this solution the incidence and severity of corner cracks for a wide range of steel grades will be considerably reduced.
For the first time in a European steel mill, two LiquiRob casting platform robots will be used at the new continuous casting machine. These will be installed in front of and behind the ladle turret – one in the ladle-positioning area and one in the ladle/tundish area on the casting platform. These robots will automatically perform a number of dangerous tasks where liquid steel is manipulated, allowing operators to monitor casting activities from the safety of the control room.
A key reason for the receipt of this contract by Siemens VAI was the excellent project and operational experience achieved with the previous upgrading of an existing caster (CCM5) at voestalpine Stahl to an ultra-thick-slab caster capable of casting 355-millimeter-thick slabs – currently the world's thickest slabs cast on a bow-type caster with a straight mold. The upgraded machine was at the end of June 2007 and has been reliably operating since then.
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