Siemens to Supply First Ultra-Thick Slab Casting System to Chinese Steel Producer

The Chinese steel producer Shougang Group Co. awarded Siemens VAI Metals Technologies a contract for the supply of a continuous-casting machine capable of casting slabs in thicknesses ranging from 250 to 400 millimeters.

Shougang will thus be the first steel producer in China capable of casting ultra-thick slabs. The caster will be installed in the existing steel works Qinhuangdao ShouQin Metals Material Co. Ltd. located in the coastal city of Qinhuangdao in Hebei Province. The slabs will be rolled to plates in an existing plate mill for use in the shipbuilding and petroleum industries. Plant start-up is scheduled for June 2010.

The Shougang Group Co. is one of the leading steel producers in China. In 2007 the company produced more than 12.4 million tons of finished steel products primarily for the domestic market, which include high-quality wire and bar, heavy plates, hot- and cold-rolled strip and sheets, as well as galvanized products. Because of environmental reasons, it was necessary for the Beijing-based Shougang Group Co. to relocate the liquid phase of its iron and steel production. A new steel works named Qinhuangdao ShouQin Metals Material Co. Ltd. – an 80:20-joint-venture company between Shougang Group Co. and the Korean industrial conglomerate Hyundai – was therefore built 270 kilometers east of Beijing in Qinhuangdao City.

For this steel works Siemens VAI Metals Technologies will supply engineering and key equipment for a continuous slab-casting machine capable of casting up to 1.1 million metric tons of steel per year. Slabs will be cast in thicknesses ranging from 250–400 millimeters and in widths from 1,600–2,400 millimeters. The casting-bow radius will be eleven meters and the metallurgical length 45 meters. To further improve the internal quality of the cast product, the vertical length of the caster will be increased by approximately one meter in comparison with conventional Siemens VAI caster designs to facilitate the flotation and removal of steel inclusions. Liquid-core unbending of 400-millimeter-thick slabs will be performed. This will enable higher casting speeds to be achieved – up to 0.7 meters per minute – and thus a higher caster output in comparison with solid-core-unbending solutions.

The Siemens scope of supply for this caster project includes detail engineering for core systems and equipment, basic engineering for the run-out area and maintenance facilities, Level 1 and Level 2 automation in addition to a wide range of technological packages. In the caster-head area the technological packages include LevCon 2 for improved automatic mold-level-control, MoldExpert 2 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 possible with DynaFlex. The technological packages for the strand-guide system include the remotely adjustable SmartBender and the subsequent SmartSegment caster segments, which, in combination with DynaGap automation, will enable the slab thickness to be quickly and fully automatically adjusted.

The Level 2 Dynacs secondary-cooling model calculates the stand-temperature profile at any position along the strand. On the basis of this information the optimum secondary-cooling setpoints as well as the point of final strand solidification are defined, taking into account the casting speed and steel grade – even during transient casting conditions. Furthermore, an improved internal strand quality will be achieved 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. With the new 3-D Spray system slabs of different widths will be ideally cooled. Only a minimum of external spray-water for machine cooling is required with I-STAR Revolver rollers, thus reducing the danger of slab-surface overcooling during the casting of ultra-thick slabs.

Additional equipment to be supplied includes molds for the casting of 250- and 400-mm-thick slabs, special parts and components for the tundish car and strand-guidance equipment, package units such as the mold-powder feeder, marking machine, roll-gap checker as well as spare parts for one year of operation. The project will be rounded off by advisory services for local manufacturing, erection, testing, start-up and commissioning in addition to personnel training.

Key reasons for the receipt of this contract by Siemens were the successful implementation of two 2-strand slab caster projects for Shougang Qian'an in December 2006 and January 2007 respectively.

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