Siemens starts up ultra-thick slab caster at Posco – Production of highest quality slabs for demanding downstream applications

In November 2007, Posco Pohang Iron & Steel Company Ltd. (Posco) placed an order for the supply of a two-strand ultra-thick, slab caster capable of casting up to 1.3 million tons of a wide range of carbon steel grades per year. The caster, designed with a metallurgical length of 24 m, was erected in the Continuous Casting Plant No. 3 (CCP3) in the Pohang Works.

Following the start-up of the caster in the two-strand casting mode, all equipment and systems functioned as designed beginning with the first heat. Slabs are cast with a thickness of either 250 mm or 400 mm, and at widths from 1,100 mm to 2,200 mm. The caster features a wide range of technological packages in the Siemens VAI product portfolio for slab casters. This includes DynaFlex for the flexible adjustment of the mold-oscillation parameters, LevCon mold-level control, DynaWidth slab-width adjustment and Smart Segments for fast slab-thickness changes.

The combination of Dynacs 3D, 3D Sprays and I-Star Revolver rollers offers a maximum in secondary cooling flexibility as the basis for achieving highest slab surface quality. Dynacs 3D calculates the temperature at any point within the strand in real time, allowing the optimum secondary-cooling setpoints to be defined. Dynamically adjustable 3D Sprays prevent overcooling of the slab corners for all slab widths. The application of I-Star Revolver rollers, which do not require spray-water cooling, supports a more gradual and uniform cooling of the slab surface. This minimizes the tendency of surface defects when casting crack-sensitive steel grades or ultra-thick slabs.

The particularly high internal quality of the slabs is ensured by the unique machine concept. A 3.6 m long vertical section at the top of the strand-guide system promotes the floating of undesired impurities present in the liquid steel. Thanks to the application of DynaGap SoftReduction, the final strand-solidification position can be precisely determined. This allows the roller-gap taper in the area of final strand solidification to be dynamically and precisely adjusted, which minimizes strand segregation as required for high-end products. The Connect & Cast capability of the installed technological packages not only shortened the installation and assembly period, but also accelerated the production ramp-up to nominal capacity.

The described slab caster is the only ultra-thick slab caster in Korea. This start-up follows the commissioning of the 400 mm ultra-thick slab caster in June 2010 at Qinhuangdao Shouqin Metal Material Co., Ltd. in Qinhuangdao City, Hebei Province, China.

Further information about solutions for steel works, rolling mills and processing lines can be found at http://www.siemens.com/metals

Dynacs, Smart, DynaGap Soft Reduction and Connect & Cast are registered trademarks of Siemens AG and/or one of its subsidiaries.

The Siemens Industry Sector (Erlangen, Germany) is the worldwide leading supplier of environmentally friendly production, transportation, building and lighting technologies. With integrated automation technologies and comprehensive industry-specific solutions, Siemens increases the productivity, efficiency and flexibility of its customers in the fields of industry and infrastructure. The Sector consists of six divisions: Building Technologies, Drive Technologies, Industry Automation, Industry Solutions, Mobility and Osram. With around 204,000 employees worldwide (September 30), Siemens Industry achieved in fiscal year 2010 total sales of approximately €34.9 billion. www.siemens.com/industry

The Siemens Industry Solutions Division (Erlangen, Germany) is one of the world's leading solution and service providers for industrial and infrastructure facilities comprising the business activities of Siemens VAI Metals Technologies, Water Technologies and Industrial Technologies. Activities include engineering and installation, operation and service for the entire life cycle. A wide-ranging portfolio of environmental solutions helps industrial companies to use energy, water and equipment efficiently, reduce emissions and comply with environmental guidelines. With around 29,000 employees worldwide (September 30), Siemens Industry Solutions posted sales of €6.0 billion in fiscal year 2010. www.siemens.com/industry-solutions