Automation increases the efficiency and quality of the surface treatment of steel tubes in the steel industry. A central computer with integrated recipe management is responsible for optimising soaking times and soaking sequence.

Tube pickling plants

When tubes are placed in tubs...

HMI of tube pickling plant (Plant overview - pool status)
HMI of tube pickling plant (Plant overview - pool status)

...they undergo a number of different processes: pickling in sulphuric acid, coating with zinc phosphate (phosphating or bonderising), neutralising, lubricating and soaping. The chemical pre-treatment of the mother tubes prepares the drawing process of seamless precision tubes.

The automation of such plants not only increases productivity, but also improves the anti-corrosion protection quality. Not least of all, it is an important contribution to workplace safety, since it is particularly in pickling processes that workers are exposed to the hazards of chemicals.

The optimisation and coordination of the soaking times reduces, amongst other things, quality losses arising from the rapid onset of corrosion from the air after passivation. In total, the automation allows for a higher throughput as the treatment pools can be used to full capacity.

The recipes for tube pickling are transmitted to the pickling control in connection with a coil ID. The control executes the job on the basis of the transmitted recipes.

Eighteen pools, one mission

For major customers from the steel industry, Eckelmann has developed a fully automated control for tube pickling plants. The plant is 40 m long and comprises 18 pools for the treatment of tubes.

A database-supported recipe management (20 to 30 recipes) is used for the calculation of the optimal soaking times and the planning of the soaking sequence (staggered soaking times). “Jams” are thus successfully prevented.

Control and visualisation

HMI of tube pickling plant (Plant overview/detailed status of pool 11)
HMI of tube pickling plant (Plant overview/detailed status of pool 11)

The plant control was implemented with a SIMATIC S7 400® from Siemens. It also comprises the drive technology control for the transport trolleys. SIMATIC WinCC® was used for the visualisation of the pickling plant. The operator can intuitively pursue the process in real time via animations.

Process data can be continuously retrieved via an interface to higher-level systems and are available to quality assurance.

  • Fully automated control of tube pickling plants
  • Coordination and optimisation of soaking times
  • Data-based recipe management
  • Intuitive process visualisation
Armin Seyffer