The first two ladle heats were successfully cast on September 20th 2011 in the new CC7 continuous casting line of voestalpine Stahl GmbH. The casting line delivered by Siemens VAI is designed to produce slabs with thicknesses up to 355 millimeters at widths of up to 2200 millimeters. For the first time in a European steelworks, two LiquiRob industrial robot systems have been installed to utilize an automated casting platform. This significantly improves the level of work safety for operating personnel. Several technological packages, including DynaGap Soft Reduction 3D, the Dynacs 3D secondary cooling system and the automatic 3D Sprays nozzle width adjustment, optimize the inner and outer slab surface quality in a wide selection of steel grades.
For the first time in a European steelworks, two LiquiRob industrial robot systems have been installed in the new CC7 continuous slab caster at the Linz production site of voestalpine Stahl GmbH. The robots have been installed in front of and behind the ladle turret, one near the ladle support and the other in vicinity of the tundish car. They assume tasks such as automatic connection of electrical and utility supply to the ladle, connection of the shroud and sliding cylinder and the unlocking of the ladle tilt hinge bolt. Procedures at the tundish such as temperature measurements, the determination of oxygen and hydrogen content, sample taking, the addition of casting powder and ladle oxygen lancing are now completely automated and carried out by the robots. The operating personnel must no longer enter potentially dangerous zones and can safely monitor and control the casting process from the control room.
For the purpose of producing high quality steel grades and in order to achieve quicker response times to changing market requirements, the continuous casting line was equipped with a wide variety of technological packages. These include the automatic LevCon mold level adjustment system, the MoldExpert strand breakout protection system, SmartMold cassette molds for rapid exchange of the copper plates and narrow faces of the mold, and DynaWidth for dynamic mold width adjustment during casting operation.
The DynaFlex mold oscillation system serves to flexibly adjust oscillation parameters. The strand guide system is equipped with the remotely adjustable Smart Bender and Smart Segments that work together with the DynaGap Soft Reduction 3D system to allow rapid and automatic slab thickness changes. EcoStar strand guide rollers are used for strand support.
The newly developed Dynacs 3D process model for secondary cooling dynamically calculates a three dimensional temperature profile along the entire strand. This calculation model can be used to determine the operating points of secondary cooling, thus precisely defining final strand solidification as dependent on the casting speed, slab format and steel grade. Improved internal slab quality homogeneity for the production of highest quality heavy plates is made possible with DynaGap Soft Reduction 3D technology. This is achieved through the precise adjustment of the roller taper in the area of final strand solidification according to the setpoints calculated by Dynacs 3D. The 3D Spray System with its movable nozzles in the segments allows homogeneous and optimized cooling of the slabs across the entire width range of 740 to 2200 millimeters. This solution can substantially reduce the occurrence and size of edge cracks for a wide variety of steel grades.
The CC7 continuous casting line is equipped with a straight mold and a bottom feeding system in order to minimize setup times and is designed for an annual production volume of 1.2 million tons of slabs. Slabs can be cast in the line in thicknesses of 225, 285 and 355 millimeters and in widths ranging between 740 and 2200 millimeters. The casting bow radius is 10 meters, and the metallurgical length is 35 meters. Roughly 70% of the produced slabs will be further processed into heavy plates. Siemens VAI was responsible for all of the engineering activities and delivered the turnkey process equipment for the casting line, including engineering, assembly and startup supervision. The project also included the basic and process automation systems.
In the Linz steelworks of voestalpine Stahl GmbH, approximately 5.5 million tons of steel are produced, cast and further processed each year into high quality coated and uncoated flat products, which are used primarily in the form of sheets and coils in the European automotive, household appliance and construction supply industries. voestalpine Stahl GmbH in Linz is continually modernizing and increasing production capacities. The target is to increase steel production in the works to approximately six million tons per year. The new casting line is intended to contribute to this increase. Continuous Caster No. 5 has been in operation since June 2007.
This caster was revamped by Siemens VAI to produce 335 millimeter slabs, the world’s first bow line with a straight mold for the casting of ultra thick slabs.
