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Steel Industry

CMI Deutschland

Mirror like through customized visualization

The stainless steel bands and sheets must be cleaned after the rolling and subsequent thermal treatment, before they are coiled up. Impurities are removed by an acid treatment. Numerous parameters like acid dosage and band control must be monitored permanently - the task of a reliable visualization software that helps to optimize the productivity of a plant by reducing the amount of chemicals necessary and by saving costs.

Initial position in the band pickling plant

More than 1,500 million tons of steel are produced worldwide every year to meet the needs of industry. However, industrial plants do not work with the slabs produced during steelmaking, but with steel sheets and bands. To do this, the slabs have to be rolled to the desired thickness and width.

When the steel is stored, deposits are formed due to the oxidation of the steel. Also during hot rolling, the heat and pressure acting on the steel create deposits on the surface that form a thin film. These impurities consist of metal oxides and are removed before the steel bands are further processed or rolled onto coils weighing several tons.

One option is to etch away these deposits using acid - this process is known as pickling. For pickling, the steel bands or sheets can be run through an acid bath. Another option for this pickling process is to spray on the acid. In continuously operating band processing lines, throughput speeds of up to 180 m/min can be achieved. In general, the challenge is to supply the acid to the process in the required quantity and concentration in order to achieve both consistent product quality and the lowest possible consumption of energy and raw materials.

Functions of the visualization software

In the latest generation of pickling plants, based on automation components from Siemens, all process-relevant data of the steel are recorded by measurement on the one hand and on the other hand additional data are read out from a product database. Software specially developed for the respective treatment steps uses this data to calculate the optimum process parameters, in particular the required dosing quantities of the individual acids and other chemicals. As a result, the conditions in the pickling process always remain constant, ensuring consistently high product quality. The precise determination and metering of the chemicals also prevents over-pickling and reduces chemical consumption by an average of 20 percent. These savings have a significant impact on overall production costs for the plant operator through reduced transportation, storage, disposal and reprocessing costs. The visualization software shows all relevant values of the pickling line at any time, from status overviews of the entire plant, all drives and all input values, to numerous detailed images. Many plant elements allow, with sufficient authentication of the operator, the input of values for the adjustment of the process up to manual operation.

For worldwide unified visualization, the integrator projects the plant schematics each with a header and footer that are always the same. The displayed texts are read out from a table via a script, and language switching is implemented quickly and easily by swapping the table.

Images modules, symbols and colors for the display of analog and digital values of pumps, valves and other devices are also standardized. focus maintains its own object library specifically for CMI UVK systems. On the one hand, this shortens the project planning of new pickling lines and, on the other hand, is part of the operating philosophy.

In addition to plant visualization, the Scada system takes on additional tasks for maintenance and servicing. The operating time of selected components is recorded by the software and compared with the respective stored maintenance interval. In this way, the operator of a plant has the possibility to minimize unplanned downtimes through preventive maintenance and to optimize the productivity of the plant. Extensive functions for report generation and trend calculation round off the visualization of the pickling line.

The functions for evaluations and maintenance help to optimize production and avoid unplanned downtimes. Operators and service personnel require less training time thanks to the standardized operator interface.

Key Facts - Automation

  • As a control system, focus relies on Simatic WinCC, the Scada and visualization software from Siemens.
  • Depending on the configuration and networking, up to 30,000 data points are recorded at the pickling lines and evaluated and displayed by the software.
  • Via TCP/IP or Profibus connection, around 100 values per second are sent to and received from controllers of other plant sections.
  • The worldwide standardized visualization is realized via the Basic Process Control (BPC) function for fast project planning of screen layout and navigation.
  • The integration of functions via C and VBS scripts in the visualization software, for example for complicated calculations and evaluations, considerably extends the range of functions.
  • The entire project including automation technology and control system is tested with the simulation software WinMOD from Mewes und Partner before delivery.
  • The result is an innovative and thorough pickling process with low acid consumption and high throughput capacity.
  • The developed standards ensure greater planning reliability for new plants and faster commissioning.