Producing Better and More: Siemens Modernizes Tandem Cold Rolling Mill of Companhia Siderúrgica Nacional in Brazil

The project also includes replacement of the automation system, renewal of the drive and process equipment as well as modification of the rolling stands, the infeed and outfeed areas and the emulsion cooling systems. The aim is to further improve product quality and to increase output. The modernized plant will start operating in the second half of 2009.

Companhia Siderúrgica Nacional has an annual crude steel capacity of 5.6 million metric tons and an annual rolled steel capacity of 5.1 million metric tons. This makes it the second largest steel producer in Brazil. The company supplies a wide range of steel products, including slabs, hot and cold rolled strip as well as zinc-plated and tin-plated products. The main customers are the distribution, packaging, automotive and household-appliance industries as well as the building sector. The main production site of CSN is located in the city of Volta Redonda in the federal state of Rio de Janeiro. Here, the five-stand tandem rolling mill No. 3 has been operating since 1982 and, with a nominal annual capacity of 1.6 million metric tons, is the most productive plant of its kind owned by CSN. Modernization will improve product quality and boost plant availability. The increased level of automation will also enhance productivity.

Under the project Siemens will modernize the drive controllers, the entire automation system, the technological control systems and the operator control system. The new equipment, which will be based on the Siroll CM concept for cold rolling mills, will see the plant fitted with a thickness control system in accordance with the advanced mass flow concept and new process models, which enable fully automatic adjustment of the rolling line to the different operating modes. Simplified operator control, integrated diagnostic systems and fully automatic rolling sequences are designed to increase the productivity of the facility.

In addition to all this, Siemens will carry out extensive renovation work on the mechanical equipment. This includes new hydraulic cylinders for all rolling stands, including servo valve stands, modifications of the mounting parts on the work rolls and on the roll changing system to ensure automatic roll change, plus additions in the infeed and outfeed areas. This will enable optimization of strip movement and further improvements in the quality of the strip surface. Comprehensive modernization of the emulsion plant rounds off the project.

The plant will be revamped as part of a scheduled shutdown in the second half of 2009. Pre-assembly and pre-commissioning of some of the functions will reduce non-productive time to a minimum. Customer training will be conducted in the context of an expanded system test in situ, and customer-specific requirements can also be integrated.

The project is being handled with the support of Siemens Brazil. The contract was awarded to Siemens based on the positive impressions left with the customer during the recently completed changeover of the drive systems of tandem line No. 2 to digital controllers and thyristor supply units. Siemens also made a positive impression with its ongoing preventive and corrective maintenance work in the Volta Redonda Continuous Casting plants.

Additional information on solutions for steel works, rolling mills and processing lines is available at http://www.siemens.com/metals.

The Siemens Industry Sector (Erlangen, Germany) is the world's leading supplier of production, transportation and building systems. Integrated hardware and software technologies combined with comprehensive industry-specific solutions enable Siemens to enhance the productivity and efficiency of its customers in industry and infrastructure. The Sector comprises six Divisions: Building Technologies, Industry Automation, Industry Solutions, Mobility, Drive Technologies and Osram. In fiscal 2007 (ended September 30), Siemens Industry generated sales of approximately EUR40 billion (pro forma, unconsolidated) with around 209,000 employees worldwide.

With the business activities of Siemens VAI Metal Technologies, (Linz, Austria), Siemens Water Technologies (Warrendale, Pa., U.S.A.), and Industry 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.